CRIMINAL EVIDENCE: EXPERT TESTIMONY
Jessica Smith, UNC School of Government (August 2017)
Table of Contents
I. Introduction. ........................................................................................................................... 3
II. Standard for Admissibility under Rule 702(a). ....................................................................... 4
A. Generally. ........................................................................................................................... 4
1. Daubert, Joiner & Kumho Tire. ................................................................................... 4
2. Effective Date of Amendments to Rule 702(a). ........................................................ 10
3. Effect of Pre-Amendment Case Law. ....................................................................... 10
B. Relevancy. ....................................................................................................................... 11
1. Generally. ................................................................................................................. 11
2. “Assist the Trier of Fact.” .......................................................................................... 11
3. “Fit” Test. .................................................................................................................. 12
4. Illustrative Cases. ..................................................................................................... 12
C. Qualifications. ................................................................................................................... 14
1. Generally. ................................................................................................................. 14
2. Illustrative Cases. ..................................................................................................... 15
D. Reliability. ......................................................................................................................... 18
1. Generally. ................................................................................................................. 18
2. Illustrative Cases. ..................................................................................................... 19
E. Procedural Issues. ........................................................................................................... 21
1. Preliminary Question of Fact. ................................................................................... 21
2. Burden of Proof. ....................................................................................................... 21
3. Flexible Inquiry. ........................................................................................................ 21
4. Findings of Fact & Conclusion of Law. ..................................................................... 22
5. Informing the Jury of Witness’s Expert Status. ......................................................... 22
F. Particular Types of Experts. ............................................................................................. 23
1. Use of Force & Self-Defense Experts. ...................................................................... 23
2. DNA Identification Evidence. .................................................................................... 25
3. Bite Mark Identification Evidence. ............................................................................ 26
4. Fingerprint Identification Evidence. .......................................................................... 27
5. Firearm Identification. ............................................................................................... 28
6. Blood Alcohol Extrapolation. ..................................................................................... 28
7. Blood Spatter Analysis. ............................................................................................ 29
8. Fiber Analysis. .......................................................................................................... 30
9. Hair Analysis. ............................................................................................................ 30
10. Shoe Print Analysis. .................................................................................................. 32
11. Handwriting Analysis. ................................................................................................ 32
12. Horizontal Gaze Nystagmus (HGN). ......................................................................... 33
13. Eyewitness Identification Experts. ............................................................................ 34
14. Drug Identification & Quantity. .................................................................................. 35
15. Fire Investigation Experts. ........................................................................................ 40
16. Accident Reconstruction. .......................................................................................... 41
17. Pathologists & Cause of Death. ................................................................................ 41
18. Polygraphs. ............................................................................................................... 42
19. Penile Plethysmography. .......................................................................................... 42
20. Experts in Crime & Criminal Practices. ..................................................................... 43
III. Form & Scope of Expert’s Opinion. ..................................................................................... 46
Criminal Evidence: Expert Testimony − 1
A. Form of Testimony. .......................................................................................................... 46
B. Opinion on Ultimate Issue & Legal Standards. ................................................................ 46
C. Opinion on Credibility of Witness. .................................................................................... 49
D. Basis for Expert’s Opinion. ............................................................................................... 50
1. Scope & Adequacy. .................................................................................................. 50
2. Of a Type Reasonably Relied Upon. ........................................................................ 50
3. Need Not Be Admissible. .......................................................................................... 51
4. Expert Need Not Interview Victim. ............................................................................ 51
5. Disclosure & Cross-Examination of Basis at Trial. ................................................... 51
6. Status as Substantive Evidence; Limiting Instruction. .............................................. 53
E. Testimony Outside of Expert’s Expertise. ........................................................................ 54
F. Terminology. .................................................................................................................... 54
IV. Interplay Between Rule 403 & the 700 Rules. ..................................................................... 54
V. Court Appointed Experts. ..................................................................................................... 55
VI. Defendant’s Right to Expert Assistance. ............................................................................. 55
VII. Standard of Review on Appeal. ........................................................................................... 56
Criminal Evidence: Expert Testimony − 2
I. Introduction. This chapter discusses the admissibility of expert testimony under North
Carolina’s amended Evidence Rule 702. The 2011 amendments to subsection (a) of the
rule adopted the federal standard for the admission of expert testimony, as articulated in
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), General Electric Co.
v. Joiner, 522 U.S. 136 (1997), and Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999).
State v. McGrady, 368 N.C. 880, 884 (2016). Before the rule was amended, making
North Carolina a “Daubert state,” the standard for admissibility of expert testimony came
from a case called Howerton v. Arai Helmet, Ltd., 358 N.C. 440 (2004). Under both the
Daubert and Howerton tests, the trial court determines admissibility of expert testimony
by examining relevancy, qualifications, and reliability. McGrady, 368 N.C. at 892.
However, under the Daubert standard the trial court applies a more rigorous reliability
analysis. Id.; see also State v. Turbyfill, ___ N.C. App. ___, 776 S.E.2d 249, 257 (2015)
(Daubert is a “heightened” standard). In its discussion of the reliability prong of the
analysis, this chapter focuses on the new Daubert standard.
For discussion of the proper scope of expert testimony in sexual assault cases,
see
Evidence Issues in Criminal Cases Involving Child Victims and Child Witnesses in
this Benchbook.
For a discussion of Confrontation Clause issues that can arise with respect to
expert testimony, see
Guide to Crawford and the Confrontation Clause in this
Benchbook.
For a discussion of what discovery must be provided in connection with expert
witnesses, see
Discovery in Criminal Cases in this Benchbook.
The text of Rule 702 is set out immediately below.
Rule 702. Testimony by experts
(a) If scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to
determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may
testify thereto in the form of an opinion, or otherwise, if all of the following apply:
(1) The testimony is based upon sufficient facts or data.
(2) The testimony is the product of reliable principles and methods.
(3) The witness has applied the principles and methods reliably to the facts of the case.
(a1) A witness, qualified under subsection (a) of this section and with proper foundation, may give expert testimony
solely on the issue of impairment and not on the issue of specific alcohol concentration level relating to the following:
(1) The results of a Horizontal Gaze Nystagmus (HGN) Test when the test is administered by a person who has
successfully completed training in HGN.
(2) Whether a person was under the influence of one or more impairing substances, and the category of such
impairing substance or substances. A witness who has received training and holds a current certification as a
Drug Recognition Expert, issued by the State Department of Health and Human Services, shall be qualified to give
the testimony under this subdivision.
[subsections (b)-(f), dealing with medical malpractice cases, are not reproduced here]
(g) This section does not limit the power of the trial court to disqualify an expert witness on grounds other than the
qualifications set forth in this section.
[subsection (h), which deals with medical malpractice cases, is not reproduced here]
(i) A witness qualified as an expert in accident reconstruction who has performed a reconstruction of a crash, or has
reviewed the report of investigation, with proper foundation may give an opinion as to the speed of a vehicle even if the
witness did not observe the vehicle moving.
Criminal Evidence: Expert Testimony − 3
Figure 1. Analysis for Determining Admissibility of Expert Testimony
II. Standard for Admissibility under Rule 702(a).
A. Generally. As illustrated in Figure 1 above, Evidence Rule 702(a) sets forth a
three-step framework for determining the admissibility of expert testimony:
relevance, qualifications, and reliability, where reliability is assessed under the
stricter Daubert standard rather than the old Howerton standard. See supra
Section I.
1. Daubert, Joiner & Kumho Tire. The “Daubert standard” refers to a
standard of admissibility laid out by the United States Supreme Court in a
trio of cases: Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579
(1993), General Electric Co. v. Joiner, 522 U.S. 136 (1997), and Kumho
Tire Co. v. Carmichael, 526 U.S. 137 (1999). Those three foundational
cases are summarized here.
Daubert was a civil case in which children and their parents sued
to recover for birth defects allegedly sustained because the mothers had
taken Bendectin, a drug marketed by the defendant pharmaceutical
company. The defendant moved for summary judgment, arguing that the
Criminal Evidence: Expert Testimony − 4
drug does not cause birth defects in humans and that the plaintiffs could
not present admissible evidence establishing otherwise. The defendant
supported its motion with an expert’s affidavit concluding that Bendectin
has not been shown to be a risk factor for human birth defects. The
plaintiffs countered with eight experts; each of whom concluded that
Bendectin can cause birth defects. The experts’ conclusions were based
on animal studies; pharmacological studies purporting to show that
Bendectin’s chemical structure was similar to that of other substances
known to cause birth defects; and the “reanalysis” of previously published
human statistical studies. Relying on the “general acceptance” test for
admission of scientific evidence formulated in Frye v. United States, 293
F. 1013 (1923), the trial court found that because it was not generally
accepted as reliable in the relevant scientific community the plaintiffs’
expert evidence was inadmissible and granted the defendant’s motion for
summary judgment. After the Ninth Circuit affirmed, the United States
Supreme Court agreed to hear the case, to resolve a split among the
courts regarding whether the “general acceptance” test was the proper
standard for admission of expert testimony.
The Court began by holding that the Frye “general acceptance”
test for admission of expert testimony was superseded by the adoption of
the Federal Rules of Evidence. Addressing the standard for admissibility
under Rule 702, the Court stated that to qualify as “scientific knowledge,”
an inference or assertion must be derived by the scientific method. 509
U.S. at 590. It explained: “[T]he requirement that an expert’s testimony
pertain to ‘scientific knowledge’ establishes a standard of evidentiary
reliability.” Id. The Court continued, noting that Rule 702 “further requires
that the evidence or testimony ‘assist the trier of fact to understand the
evidence or to determine a fact in issue,’” a condition going primarily to
relevance. Id. at 591. It clarified: “Expert testimony which does not relate
to any issue with the case is not relevant and, ergo, non-helpful.” Id.
(quotation omitted). This prong of the admissibility analysis, it noted, has
been described as one of “fit.” Id. It continued:
Faced with a proffer of expert scientific testimony . . . , the
trial judge must determine at the outset, pursuant to Rule
104(a), whether the expert is proposing to testify to (1)
scientific knowledge that (2) will assist the trier of fact to
understand or determine a fact in issue. This entails a
preliminary assessment of whether the reasoning or
methodology underlying the testimony is scientifically valid
and of whether that reasoning or methodology properly
can be applied to the facts in issue.
Id. at 592–93 (footnotes omitted). The Court noted that many factors will
bear on the inquiry and that it would not “presume to set out a definitive
checklist or test.” Id. at 593. However, it went on to offer five “general
observations” relevant to the analysis:
1. A “key question” is whether the theory or technique can be (and
has been) tested. Id. (“Scientific methodology . . . is based on
generating hypotheses and testing them to see if they can be
Criminal Evidence: Expert Testimony − 5
falsified; indeed, this methodology is what distinguishes science
from other fields of human inquiry” (quotation omitted)).
2. Whether the theory or technique has been subjected to peer
review and publication. Id. The Court noted that publication (one
element of peer review) is not a “sine qua non of admissibility;”
publication does not necessarily correlate with reliability, and in
some cases well-grounded but innovative theories will not have
been published. Id. It explained: “Some propositions . . . are too
particular, too new, or of too limited interest to be published. But
submission to the scrutiny of the scientific community is a
component of ‘good science,’ in part because it increases the
likelihood that substantive flaws in methodology will be detected.”
Id. Thus, “[t]he fact of publication (or lack thereof) in a peer
reviewed journal . . . will be a relevant, though not dispositive,
consideration in assessing the scientific validity of a particular
technique or methodology on which an opinion is premised.” Id. at
594.
3. The theory or technique’s known or potential rate of error. Id. at
594.
4. The existence and maintenance of standards controlling the
technique’s operation. Id.
5. The “general acceptance” of the theory or technique. Id. at 594.
The Court explained:
“A reliability assessment does not require, although
it does permit, explicit identification of a relevant
scientific community and an express determination
of a particular degree of acceptance within that
community. Widespread acceptance can be an
important factor in ruling particular evidence
admissible, and a known technique which has been
able to attract only minimal support within the
community may properly be viewed with
skepticism.”
Id. (quotations and citations omitted).
The Court was careful to note that the inquiry to be applied by the trial
court in its “gatekeeping role,” id. at 597, is “a flexible one” in which the
focus “must be solely on principles and methodology, not on the
conclusions that they generate.” Id. at 594-95. In the end, the Court
remanded for further proceedings consistent with the new test for
admissibility. Id. at 597-98.
The second case in the Daubert trilogy was Joiner, another civil
case. Joiner, 522 U.S. 136. Its main contribution to the trilogy is to
establish that a trial court’s decision to admit or exclude expert testimony
under Federal Rule 702 is reviewed under an abuse of discretion
standard and to illustrate application of that standard to a trial court’s
exclusion of expert testimony. In Joiner, an electrician who had lung
cancer sued the manufacturer of PCBs and the manufacturers of
electrical transformers and dielectric fluid for damages. The plaintiff, who
Criminal Evidence: Expert Testimony − 6
was a smoker and had a family history of lung cancer, claimed that his
exposure on the job to PCBs and their derivatives promoted his cancer. In
deposition testimony, the plaintiff’s experts opined that his exposure to
PCBs was likely responsible for his cancer. The district court found the
testimony from these experts to be inadmissible and granted the
defendants’ motion for summary judgment. The Eleventh Circuit reversed
and the Supreme Court granted certiorari.
The Court held that a trial court’s decision to admit or exclude
expert testimony will be reviewed under an abuse of discretion standard
and that here, no abuse of discretion occurred. Id. at 143. The plaintiff
proffered the deposition testimony of two expert witnesses: (1) Dr. Arnold
Schecter, who testified that he believed it “more likely than not that [the
plaintiff’s] lung cancer was causally linked to cigarette smoking and PCB
exposure;” and (2) Dr. Daniel Teitlebaum, who testified that the plaintiff’s
“lung cancer was caused by or contributed to in a significant degree by
the materials with which he worked.” Id. The defendants asserted that the
experts’ statements regarding causation were speculation, unsupported
by epidemiological studies and based exclusively on isolated studies of
laboratory animals. Id. The plaintiff responded, claiming that his experts
had identified animal studies to support their opinions and directing the
court to four epidemiological studies relied upon by his experts. Id. at 143-
44. The district court had agreed with the defendants that the animal
studies did not support the plaintiff’s contention that PCB exposure
contributed to his cancer. Id at 144. The studies involved infant mice that
developed cancer after being exposed to massive doses of concentrated
PCBs injected directly into their bodies. Id. The plaintiff, by contrast, was
an adult human whose alleged exposure was far less and in lower
concentrations. Id. Also, the cancer that the mice developed was different
than the plaintiff’s cancer, no study demonstrated that adult mice
developed cancer after being exposed to PCBs, and no study
demonstrated that PCBs lead to cancer in other species. Id. The Court
concluded: “[t]he studies were so dissimilar to the facts presented in this
litigation that it was not an abuse of discretion for the District Court to
have rejected the experts’ reliance on them.” Id. at 144-45.
The trial court also had concluded that the epidemiological studies
were not a sufficient basis for the experts’ opinions. After reviewing the
studies, the Court found that they did not sufficiently suggest a link
between the increase in lung cancer deaths and exposure to PCBs. Id. at
145-46. The Court went on to disagree with the plaintiff’s assertion that
Daubert requires a focus “solely on principles and methodology,” not the
conclusions that they generate, and that the trial court erred by focusing
on the experts’ conclusions, stating:
[C]onclusions and methodology are not entirely distinct
from one another. Trained experts commonly extrapolate
from existing data. But nothing in either Daubert or the
Federal Rules of Evidence requires a district court to admit
opinion evidence that is connected to existing data only by
the ipse dixit of the expert. A court may conclude that there
is simply too great an analytical gap between the data and
the opinion proffered.
Criminal Evidence: Expert Testimony − 7
Id. at 146. The Court went on to hold that the trial court did not abuse its
discretion by concluding that the studies on which the experts relied were
not sufficient to support their conclusions that the plaintiff’s exposure to
PCBs contributed to his cancer. Id. at 146-47.
The final case in the trio was Kumho Tire, 526 U.S. 137. It
answered a question left open by Daubert: Does the Daubert standard
apply only to “scientific” expert testimony or to all expert testimony,
including testimony based on technical or other specialized knowledge?
The Court held that the test applies to all expert testimony. In Kumho Tire
the Court also clarified the nature of the Daubert inquiry.
In Kumho Tire, the plaintiffs brought a products liability action
against a tire manufacturer and distributor for injuries sustained when a
vehicle tire failed. The plaintiffs rested their case on deposition testimony
provided by an expert in tire failure analysis, Dennis Carlson. Carlson’s
testimony accepted certain background facts about the tire in question,
including that it had traveled far; that the tire’s tread depth had been worn
down to depths that ranged from 3/32 of an inch to zero; and that the tire
tread had at least two inadequately repaired punctures. Despite the tire’s
age and history, Carlson concluded that a defect in the tire’s manufacture
or design caused the blowout. His conclusion rested on several
undisputed premises, including that the tread had separated from the
inner carcass and that this “separation” caused the blowout. Id. at 143-44.
However, his conclusion also rested on several disputed propositions.
First, Carlson said that if a separation is not caused by a kind of misuse
called “overdeflection” then ordinarily its cause is a tire defect. Second,
that if a tire has been subject to sufficient overdeflection to cause a
separation, it should reveal certain symptoms, which he identified. Third,
that where he does not find at least two such symptoms, he concludes
that a manufacturing or design defect caused the separation. Carlson
conceded that the tire showed a number of symptoms, but in each
instance he found them to be not significant and he explained why he
believed they did not reveal overdeflection. He thus concluded that a
defect must have caused the blowout.
The defendant moved to exclude Carlson’s testimony on the
ground his methodology failed Rule 702’s reliability requirement. The trial
court conducted a Daubert reliability analysis and granted the motion to
exclude. The Eleventh Circuit reversed, holding that the Daubert analysis
only applied to scientific evidence. The United States Supreme Court
granted certiorari to resolve the question of whether or how Daubert
applies to expert testimony based not on “scientific” knowledge but on
“technical” or “other specialized” knowledge.
The Supreme Court began by holding that the Daubert standard
applies to all expert testimony, not just scientific testimony. Id. at 147-49.
It went on to hold that when determining the admissibility of the expert
testimony at issue--engineering testimony--the trial court may consider
the five Daubert factors: whether the theory or technique can and has
been tested; whether it has been subjected to peer review and
publication; the theory or technique’s known or potential rate of error;
whether there are standards controlling its operation; and whether the
theory or technique enjoys general acceptance within the relevant
Criminal Evidence: Expert Testimony − 8
scientific community. Id. at 149-50. Emphasizing the word “may” in this
holding, the Court explained:
Engineering testimony rests upon scientific foundations,
the reliability of which will be at issue in some cases. In
other cases, the relevant reliability concerns may focus
upon personal knowledge or experience. . . . [T]here are
many different kinds of experts, and many different kinds of
expertise. . . . We agree . . . that “[t]he factors identified in
Daubert may or may not be pertinent in assessing
reliability, depending on the nature of the issue, the
expert's particular expertise, and the subject of his
testimony.” The conclusion, in our view, is that we can
neither rule out, nor rule in, for all cases and for all time the
applicability of the factors mentioned in Daubert, nor can
we now do so for subsets of cases categorized by category
of expert or by kind of evidence. Too much depends upon
the particular circumstances of the particular case at issue.
Id. at 150 (quotations and citations omitted). It continued:
Daubert . . . made clear that its list of factors was meant to
be helpful, not definitive. Indeed, those factors do not all
necessarily apply even in every instance in which the
reliability of scientific testimony is challenged. It might not
be surprising in a particular case, for example, that a claim
made by a scientific witness has never been the subject of
peer review, for the particular application at issue may
never previously have interested any scientist. Nor, on the
other hand, does the presence of Daubert's general
acceptance factor help show that an expert's testimony is
reliable where the discipline itself lacks reliability, as, for
example, do theories grounded in any so-called generally
accepted principles of astrology or necromancy.
At the same time . . . some of Daubert's questions
can help to evaluate the reliability even of experience-
based testimony. In certain cases, it will be appropriate for
the trial judge to ask, for example, how often an
engineering expert's experience-based methodology has
produced erroneous results, or whether such a method is
generally accepted in the relevant engineering community.
Likewise, it will at times be useful to ask even of a witness
whose expertise is based purely on experience, say, a
perfume tester able to distinguish among 140 odors at a
sniff, whether his preparation is of a kind that others in the
field would recognize as acceptable.
Id. at 151. The Court emphasized that the purpose of Daubert’s
gatekeeping requirement “is to make certain that an expert, whether
basing testimony upon professional studies or personal experience,
employs in the courtroom the same level of intellectual rigor that
Criminal Evidence: Expert Testimony − 9
characterizes the practice of an expert in the relevant field.” Id. at 152. It
further emphasized the considerable leeway that must be afforded to the
trial court in determining whether particular expert testimony is reliable. Id.
It clarified that when assessing reliability, the trial court must have
flexibility in determining whether special briefing or other proceedings are
necessary, and that, as it held in Joiner, the court’s decision will be
reviewed under an abuse of discretion standard. Id.
Turning to the case at hand, the Court held that the trial court did
not abuse its discretion by excluding the testimony. The district court had
found unreliable the methodology employed by the expert in analyzing the
data obtained through his inspection of the tire, and the scientific basis, if
any, for his analysis. The Court noted that, among other things, the trial
court could reasonably have wondered whether the expert’s method of
visual and tactile inspection was sufficiently precise, and these concerns
might have been amplified by Carlson’s repeated reliance on the
subjectiveness of his analysis and the fact that he had inspected the tire
for the first time the morning of his deposition, and only for a few hours,
having based his initial conclusions on photographs. Id. at 155.
Additionally, the trial court found that none of the Daubert factors,
including that of general acceptance, indicated that Carlson’s testimony
was reliable. Id. at 156. With respect to Carlson’s claim that his method
was accurate, the court noted that, as stated in Joiner, “nothing . . .
requires a district court to admit opinion evidence that it is connected to
existing data only by the ipse dixit of the expert.” Id. at 157. For these and
other reasons, the Court concluded that the trial court did not abuse its
discretion by excluding the expert testimony. Id. at 158.
Stated broadly, these three cases hold that when assessing any
type of expert testimony under Rule 702, the Daubert standard applies;
the inquiry is a flexible one; and the trial court will be reversed only for an
abuse of discretion.
2. Effective Date of Amendments to Rule 702(a). As noted above, the
2011 amendments to Rule 702(a) incorporate the Daubert standard. The
amendments to section 702(a) apply to “actions commenced” on or after
October 1, 2011. See S.L. 2011-283, secs. 1.3, 4.2. “[T]he trigger date”
for applying the amended version of the rule is the date that the bill of
indictment is filed. State v. Walston, 229 N.C. App. 141, 152 (2013), rev’d
on other grounds, 367 N.C. 721 (2014); State v. McLaughlin, ___ N.C.
App. ___, 786 S.E.2d 269, 286 (2016); State v. Gamez, 228 N.C. App.
329, 332-33 (2013). If a second indictment is filed on or after October 1,
2011 and is joined for trial with an indictment filed before the statute’s
effective date, the proceeding is deemed to have commenced on the date
the first indictment was filed. Gamez, 228 N.C. App. at 333. However, in a
case involving one indictment in which a superseding indictment is filed,
the date of the superseding indictment controls. Walston, 229 N.C. App.
at 152.
3. Effect of Pre-Amendment Case Law.
The North Carolina Supreme Court has stated that the 2011 amendments
did not abrogate all North Carolina precedents interpreting that rule.
Specifically, it has stated: “Our previous cases are still good law if they do
not conflict with the Daubert standard.” State v. McGrady, 368 N.C. 880,
Criminal Evidence: Expert Testimony − 10
at 888 (2016). It is not entirely clear what that statement means. The
2011 amendments adopting the Daubert standard changed only the
reliability prong of the Rule 702 analysis; the relevancy and qualifications
prongs were not changed. Thus, this Chapter assumes that this
statement means: (1) that cases applying the relevancy and qualifications
prongs of the analysis remain good law; and (2) that cases applying the
more lenient pre-Daubert standard to the reliability prong are inconsistent
with the analysis under the new Daubert rule. However, cases applying
the pre-Daubert standard to the reliability prong to hold that evidence is
inadmissible are likely to be consistent with a result that obtains from
application of the Daubert standard (after all, evidence that could not pass
muster under the earlier standard is unlikely to do so under the new
stricter standard). By contrast, cases applying the more lenient pre-
Daubert standard to the reliability prong to hold that evidence is
admissible may not be consistent with a result that obtains under the
stricter Daubert test, and perhaps should be viewed with some
skepticism.
B. Relevancy.
1. Generally. Rule 702 requires that the testimony “will assist the trier of fact
to understand the evidence or to determine a fact in issue.” This prong of
the analysis is referred to as the “relevancy test.” Daubert, 509 U.S. at
591 (“This condition goes primarily to relevance. Expert testimony which
does not relate to any issue in the case is not relevant and, ergo, non-
helpful.” (quotation omitted)); see also McGrady, 368 N.C. at 889. As with
any evidence, the expert testimony must meet the minimum standard for
logical relevance under Rule 401. McGrady, 368 N.C. at 889. “In other
words, the testimony must ‘relate to [an] issue in the case.’” Id. (quoting
Daubert); see also State v. Oakes, 209 N.C. App. 18, 28-29 (2011) (the
defendant was not prejudiced by the trial court’s decision to exclude
testimony by the defendant’s use of force expert on the issue of the
defendant’s intent to kill where intent to kill was irrelevant to the charge of
felony-murder); see generally
Relevancy in this Benchbook (discussing
relevancy under Rule 401).
2. “Assist the Trier of Fact.” As used in this prong of the inquiry, the term
relevance means something more than standard relevancy under Rule
401. McGrady, 368 N.C. at 889. As the North Carolina Supreme Court
has explained, “In order to ‘assist the trier of fact,’ expert testimony must
provide insight beyond the conclusions that jurors can readily draw from
their ordinary experience.” Id. (going on to note: “An area of inquiry need
not be completely incomprehensible to lay jurors without expert
assistance before expert testimony becomes admissible. To be helpful,
though, that testimony must do more than invite the jury to substitute the
expert’s judgment of the meaning of the facts of the case for its own”
(citation and quotation omitted)). Thus, in McGrady, the court held that
the trial court did not abuse its discretion by excluding a defense expert
proffered to testify to “pre-attack cues” and “use of force variables” to
support the defense of self-defense and defense of others. 368 N.C. at
894-95. According to the expert, pre-attack cues are actions “exhibited by
an aggressor as a possible precursor to an actual attack” including
“actions consistent with an assault, actions consistent with retrieving a
Criminal Evidence: Expert Testimony − 11
weapon, threats, display of a weapon, employment of a weapon, profanity
and innumerable others.” Id. at 894. He said that “use of force variables”
refer to circumstances and events that influence a person's decision
about the type and degree of force necessary to repel a perceived threat,
such as the age, gender, size, and number of individuals involved; the
number and type of weapons present; and environmental factors. Id. at
895. The court held that the trial court did not abuse its discretion by
concluding that the expert’s testimony about pre-attack cues and use of
force variables would not assist the jury because these matters were
within the jurors' common knowledge. The court noted: the factors the
expert “cited and relied on to conclude that defendant reasonably
responded to an imminent, deadly threat are the same kinds of things that
lay jurors would be aware of, and would naturally consider, as they drew
their own conclusions.” Id.
3. “Fit” Test. Another aspect of relevancy is the “fit” of the expert testimony
to the facts of the case. Daubert, 509 U.S. at 591-92. As referred to in this
way, the fit test ensures that proffered “‘expert testimony . . . is sufficiently
tied to the facts of the case that it will aid the jury in resolving a factual
dispute.’” State v. Babich, ___ N.C. App. ___, 797 S.E.2d. 359, 362
(2017) (quoting Daubert). Thus for example, the North Carolina Court of
Appeals held that expert testimony on retrograde extrapolation that
assumed, with no evidence, that the defendant was in a post-absorptive
state failed the fit test and was inadmissible. Id. Issues of “fit” overlap with
the third-prong of the reliability analysis, that the witness has applied the
principles and methods reliably to the facts of the case, as discussed
below in Section II.D.
4. Illustrative Cases. Illustrative cases addressing this prong of the test are
annotated below. Because this prong of the Rule 702(a) admissibility
inquiry was not altered by the 2011 amendments to the rule, the cases
listed below include those decided both before and after the 2011
amendments.
State v. McGrady, 368 N.C. 880, 894–95 (2016). In this murder
case, the trial court did not abuse its discretion by excluding a
defense expert proffered to testify to “pre-attack cues” and “use of
force variables” to support the defense of self-defense and
defense of others. The expert’s report stated that pre-attack cues
are actions “exhibited by an aggressor as a possible precursor to
an actual attack” including “actions consistent with an assault,
actions consistent with retrieving a weapon, threats, display of a
weapon, employment of a weapon, profanity and innumerable
others.” He indicated that “use of force variables” refer to
additional circumstances and events that influence a person's
decision about the type and degree of force necessary to repel a
perceived threat, such as age, gender, size, and number of
individuals involved; the number and type of weapons present;
and environmental factors. The trial court did not abuse its
discretion by concluding that the expert’s testimony about pre-
attack cues and use of force variables would not assist the jury
because these matters were within the jurors' common
Criminal Evidence: Expert Testimony − 12
knowledge. The court noted: the factors the expert “cited and
relied on to conclude that defendant reasonably responded to an
imminent, deadly threat are the same kinds of things that lay
jurors would be aware of, and would naturally consider, as they
drew their own conclusions.” In fact, the expert’s own report stated
that, even without formal training, individuals recognize and
respond to these cues and variables when assessing a potential
threat.
State v. Babich, ___ N.C. App. ___, 797 S.E.2d. 359, 361-64
(2017). Holding that an expert’s retrograde extrapolation testimony
that assumed, with no evidence, that the defendant was in a post-
absorptive state failed the “fit” test and was inadmissible. The
court held:
[W]hen an expert witness offers a retrograde
extrapolation opinion based on an assumption that
the defendant is in a post-absorptive or post-peak
state, that assumption must be based on at least
some underlying facts to support that assumption.
This might come from the defendant's own
statements during the initial stop, from the arresting
officer's observations, from other witnesses, or from
circumstantial evidence that offers a plausible
timeline for the defendant's consumption of alcohol.
When there are at least some facts that can
support the expert's assumption that the defendant
is post-peak or post-absorptive, the issue then
becomes one of weight and credibility, which is the
proper subject for cross-examination or competing
expert witness testimony. But where, as here, the
expert concedes that her opinion is based entirely
on a speculative assumption about the defendant—
one not based on any actual facts—that testimony
does not satisfy the Daubert “fit” test because the
expert's otherwise reliable analysis is not properly
tied to the facts of the case.
State v. Daughtridge, ___ N.C. App. ___, 789 S.E.2d 667, 675-76
(2016). The trial court improperly allowed a medical examiner to
testify, as an expert in forensic pathology, that the victim’s death
was a homicide when that opinion was based not on medical
evidence but rather on non-medical information provided to the
expert by law enforcement officers involved in the investigation of
the victim’s death. The State failed to adequately explain how the
medical examiner was in a better position than the jurors to
evaluate whether the information provided by the officers was
more suggestive of a homicide than a suicide.
State v. Martin, 222 N.C. App. 213, 216–18 (2012). The trial court
did not abuse its discretion by excluding testimony by a defense
Criminal Evidence: Expert Testimony − 13
proffered “forensic scientist and criminal profiler.” During voir dire
the witness identified what he considered to be inconsistencies in
the victim’s version of events leading up to and during the alleged
sexual assaults and evidence consistent with what he described
as “investigative red flags.” The witness’s testimony, which would
have discredited the victim’s account of the defendant's action on
the night in question and commented on the manner in which the
criminal investigation was conducted “appears to invade the
province of the jury.”
State v. Fox, 58 N.C. App. 231, 233 (1982). The trial court did not
err by refusing to allow a psychiatrist testifying as an expert
witness to give his opinion that the defendant believed he was
acting in self-defense. The court held: “we do not find error in the
trial court's conclusion that it was for the jury to ascertain
defendant's motive for the killing.” The court concluded that the
expert
certainly was qualified to give an opinion as to [the
defendant’s] mental capacity and any mental
disorders he may have identified, and the record
shows he was permitted to do so. Indeed, the
psychiatrist was permitted to testify that defendant
had told him he had acted in the belief that the
victim was going to kill him and that he had been
frightened. We find nothing in the record to indicate
that the witness was better qualified than the jury to
judge the defendant's veracity based on all the
evidence.
C. Qualifications.
1. Generally. The second requirement for admissibility of expert testimony
is that the witness must be “qualified as an expert by knowledge, skill,
experience, training, or education.” N.C.
R. EVID. 702(a). “This portion of
the rule focuses on the witness's competence to testify as an expert in the
field of his or her proposed testimony.” McGrady, 368 N.C. at 889. It asks:
“Does the witness have enough expertise to be in a better position than
the trier of fact to have an opinion on the subject?” Id.
The North Carolina Supreme Court has noted that “[e]xpertise can
come from practical experience as much as from academic training” and
that:
The rule does not mandate that the witness always have a
particular degree or certification, or practice a particular
profession. But this does not mean that the trial court cannot
screen the evidence based on the expert's qualifications. In
some cases, degrees or certifications may play a role in
determining the witness's qualifications, depending on the
content of the witness's testimony and the field of the
witness's purported expertise.
Criminal Evidence: Expert Testimony − 14
Id. at 889-90. It also has noted that “[d]ifferent fields require different
‘knowledge, skill, experience, training, or education,’” id. at 896,
explaining:
For example, a witness with a Ph.D. in organic chemistry
may be able to describe in detail how flour, eggs, and
sugar react on a molecular level when heated to 350
degrees, but would likely be less qualified to testify about
the proper way to bake a cake than a career baker with no
formal education.
Id.
Once a witness is found to be qualified to testify as an
expert, issues sometimes arise about whether the expert is being
asked to testify outside of his or her area of expertise. For a
discussion of that issue, see Section III.E. below.
2. Illustrative Cases. Examples of North Carolina cases addressing this
prong of the test are provided below. This list is meant to be
illustrative, not exhaustive. Because this prong of the Rule 702(a)
admissibility inquiry was not altered by the 2011 amendments to
the rule, the cases below include those decided both before and
after the 2011 amendments to the Rule.
State v. McGrady, 368 N.C. 880, 895–96 (2016). In this
murder case, the trial court did not abuse its discretion by
concluding that a defense expert, Mr. Cloutier, was not
qualified to offer expert testimony on the stress responses
of the sympathetic nervous system. Cloutier’s report stated
that an instinctive survival response to fear “can activate
the body's sympathetic nervous system” and the “‘fight or
flight’ response.” He indicated that the defendant's
perception of an impending attack would cause an
adrenalin surge “activat[ing] instinctive, powerful and
uncontrollable survival responses.” He maintained that this
nervous system response causes “perceptual narrowing,”
focusing a person's attention on the threat and leading to a
loss of peripheral vision and other changes in visual
perception. According to Cloutier, this nervous system
response also can cause “fragmented memory,” or an
inability to recall events. The expert, a former police officer,
testified that he was not a medical doctor but had studied
“the basics” of the brain in general college psychology
courses. He also testified that he had read articles and
been trained by medical doctors on how adrenalin affects
the body, had personally experienced perceptual
narrowing, and had trained numerous police officers and
civilians on how to deal with these stress responses.
Noting that Rule 702(a) “does not create an across-the-
board requirement for academic training or credentials,”
the court held that it was not an abuse of discretion to
require a witness who intended to testify about the
Criminal Evidence: Expert Testimony − 15
functions of an organ system to have some formal medical
training.
State v. Morgan, 359 N.C. 131, 159–61 (2004). The trial
court did not abuse its discretion by holding that the State’s
witness was qualified to testify as an expert in the field of
bloodstain pattern interpretation where the witness
completed two training sessions on bloodstain pattern
interpretation, had analyzed bloodstain patterns in dozens
of cases, had previously testified in a homicide case as a
bloodstain pattern interpretation expert, and described in
detail to the judge and jury the difference between blood
spatter and transfer stains and produced visual aids to
illustrate his testimony. The witness’s “qualifications are
not diminished, as defendant suggests, by the fact that he
has never written an article, lectured, or taken a college-
level course on bloodstain or blood spatter analysis.”
State v. Cooper, 229 N.C. App. 442, 461-63 (2013). In this
murder case where files recovered from the defendant’s
computer linked the defendant to the crime, the trial court
abused its discretion by concluding that a defense expert
proffered to testify that the defendant’s computer had been
tampered with was not qualified to give expert testimony.
The witness had worked for many years in the computer
field, specializing in computer network security. However,
the witness had no training and experience as a forensic
computer analyst. The trial court erred by concluding that
because the digital data in question was recovered using
forensic tools and methods, only an expert forensic
computer analyst was qualified to interpret and form
opinions based on the data recovered. It concluded:
“Nothing in evidence supports a finding that [the expert]
was not qualified to testify using the data recovered by the
State. [The expert], based upon expertise acquired through
practical experience, was certainly better qualified than the
jury to form an opinion as to the subject matter to which his
testimony applie[d].” (quotation and citation omitted).
State v. Dew, 225 N.C. App. 750, 760-61 (2013). In this
child sex case, the trial court did not err by qualifying as an
expert a family therapist who provided counseling to the
victims. Among other things, the witness had a master’s
degree in Christian counseling and completed additional
professional training relating to the trauma experienced by
children who have been sexually abused; she engaged in
private practice as a therapist and was a licensed family
therapist and professional counselor; and over half of her
clients had been subjected to some sort of trauma, with a
significant number having suffered sexual abuse.
Criminal Evidence: Expert Testimony − 16
State v. Britt, 217 N.C. App. 309, 314-15 (2011). SBI
agents were properly qualified to give expert testimony
regarding firearm tool mark identification.
State v. Norman, 213 N.C. App. 114, 122-24 (2011). The
trial court did not abuse its discretion by qualifying the
State’s witness, Mr. Glover, as an expert in the fields of
forensic blood alcohol physiology and pharmacology,
breath and blood alcohol testing, and the effects of drugs
on human performance and behavior. Glover was the head
of NC Department of Health and Human Services Forensic
Test for Alcohol branch. He oversaw training of officers on
the operation of alcohol breath test instruments and of
drug recognition experts, who observed the effects of
drugs in individuals. Glover had a bachelor of science and
a master's degree in biology and was certified as a
chemical analyst on breath test instruments used in North
Carolina. He attended courses at Indiana University
regarding the effects of alcohol on the human body, the
various methods for determining alcohol concentrations,
and on the effects of drugs on human psychomotor
performance. Glover published several works and
previously had been qualified as an expert in forensic
blood alcohol physiology and pharmacology, breath and
blood alcohol testing, and the effects of drugs on human
performance and behavior over 230 times in North
Carolina. The court concluded that despite Glover’s lack of
a formal degree or certification in the fields of physiology
and pharmacology, his extensive practical experience
qualified him to testify as an expert. See also State v.
Green, 209 N.C. App. 669, 672-75 (2011) (holding that the
trial court did not abuse its discretion by finding that Glover
was qualified to testify as an expert in the areas of
pharmacology and physiology).
State v. Norton, 213 N.C. App. 75, 80-81 (2011). The trial
court did not abuse its discretion by finding that a forensic
toxicologist was qualified to testify about the effects of
cocaine on the body. The court concluded: “As a trained
expert in forensic toxicology with degrees in biology and
chemistry, the witness . . . was plainly in a better position
to have an opinion on the physiological effects of cocaine
than the jury.”
State v. Hargrave, 198 N.C. App. 579, 584-85 (2009). The
court rejected the defendant’s argument that the trial court
erred by admitting testimony from the State lab technician
(who testified that the substances found by law
enforcement contained cocaine) because the expert did
not have an advanced degree. The witness had a
Bachelor’s degree in chemistry, completed basic law
Criminal Evidence: Expert Testimony − 17
enforcement training and in-house training to be a forensic
drug chemist and testified as an expert in that field on
approximately forty previous occasions.
D. Reliability.
1. Generally. The third requirement of Rule 702(a) is the three-pronged
reliability test that is new to the amended rule:
(1) the testimony must be based upon sufficient facts or data;
(2) the testimony must be the product of reliable principles and
methods; and
(3) the witness must have applied the principles and methods
reliably to the facts of the case.
N.C.
R. EVID. 702(a). These three prongs together constitute the reliability
inquiry discussed in the Daubert line of cases, McGrady, 368 N.C. at 890,
discussed in Section II.A.1. above. Citing extensively from those cases,
the North Carolina Supreme Court has noted that:
• Although the primary focus of this inquiry is the reliability of the
witness's principles and methodology, not the conclusions that
they generate, conclusions and methodology are not entirely
distinct. Thus, when a trial court concludes that there is simply too
great an analytical gap between the data and the opinion
proffered, “the court is not required to admit opinion evidence that
is connected to existing data only by the ipse dixit of the expert.”
McGrady, 368 N.C. at 890 (quotations and citations omitted).
• “The precise nature of the reliability inquiry will vary from case to
case depending on the nature of the proposed testimony” and the
trial court has discretion in determining how to address the
reliability analysis. Id.
• The five factors identified in Daubert (whether the theory or
technique can and has been tested; whether it has been
subjected to peer review and publication; the theory or
technique’s known or potential rate of error; whether there are
standards controlling its operation; and whether the theory or
technique enjoys general acceptance within the relevant scientific
community) bear on the reliability of the evidence, but the trial
court should use whatever factors it thinks most appropriate for
the inquiry. Id.
• Other factors considered by courts in the reliability inquiry include
whether:
(1) the expert is testifying based on research conducted
independent of the litigation;
(2) the expert has unjustifiably extrapolated from an accepted
premise to an unfounded conclusion;
(3) the expert has adequately accounted for obvious
alternative explanations;
Criminal Evidence: Expert Testimony − 18
(4) the expert has employed the same care in reaching
litigation-related opinions as the expert employs in
performing the expert’s regular professional work; and
(5) the field of expertise claimed by the expert is known to
reach reliable results for the type of opinion the expert
would give.
McGrady, 368 N.C. at 891.
• The inquiry remains a flexible one; neither Daubert’s five factors
nor this additional list of factors constitute a checklist; the trial
court is free to consider other factors, depending on the type of
testimony at issue. Id. at 891-92.
Cases decided since McGrady have reiterated these points. See, e.g.,
State v. Hunt, ___ N.C. App. ___, 790 S.E.2d 874, 881 (2016); State v.
Turbyfill, ___ N.C. App. ___, 776 S.E.2d 249, 258 (2015).
Note that the third-part of the reliability analysis—that the witness
has applied the principles and methods reliably to the facts of the case—
overlaps, in some respect, with issues of “fit” with respect to the relevancy
prong of the analysis, discussed above in Section II.B.3.
2. Illustrative Cases. Examples of North Carolina cases applying Daubert
to this prong of the analysis include:
State v. McGrady, 368 N.C. 880, 897–99 (2016). In this
murder case, the trial court did not abuse its discretion by
concluding that a defense expert’s testimony regarding
reaction times was unreliable. The testimony was offered
to rebut any assumption in the jurors' minds that the
defendant could not have acted defensively if he shot the
victim in the back. Because the expert testified on voir dire
that he interviewed the defendant and other witnesses;
reviewed interviews of the defendant and a witness, the
case file, and physical evidence collected by the Sherriff's
Department; and visited the crime scene, the expert’s
testimony satisfied the “sufficient facts or data” requirement
in Rule 702(a)(1). However, the expert based his testimony
about average reaction times on statistics from two
studies, but did not know whether or not those studies
reported error rates and, if so, what those error rates were.
Thus, a trial judge could reasonably conclude that the
expert’s degree of unfamiliarity with the studies rendered
unreliable his testimony about them and the conclusions
about the case that he drew from them. Also, while the
expert established that a disability could affect reaction
time, he failed to account for the defendant’s back injury in
his analysis. This failure relates both to the sufficiency of
the facts and data relied upon and to whether the expert
applied his own methodology reliably in this case.
State v. Hunt, 790 N.C. App. 874, 877, 880-81 (2016). In this drug
case, the trial court properly allowed the State’s witness, a special
Criminal Evidence: Expert Testimony − 19
agent and forensic chemist with the State Crime Lab, to testify as
an expert in forensic chemistry. The expert testified that following
Crime Lab administrative procedure, he applied a testing
procedure called the “administrative sample selection” to the
pharmaceutically manufactured pills in question. This involves
visually inspecting the shape, color, texture, and manufacturer's
markings or imprints of all units and comparing them to an online
database to determine whether the pills are pharmaceutically
prepared. After the chemist determines that the units are similar
and not counterfeit, the protocol requires the chemist to weigh the
samples, randomly select one, and chemically analyze that tablet,
using gas chromatography and a mass spectrometer. The expert
testified that upon receiving the pills, he divided them into four
categories based on their physical characteristics. Using
administrative sample selection, he tested one pill from the first
three groups. Each tested positive for oxycodone. The combined
weight of the pills in these categories exceeded the trafficking
amount. Upon inspecting the pills that he did not chemically
analyze according to their physical characteristics, he found them
consistent with a pharmaceutical preparation containing
oxycodone. The court held that, based on the expert’s detailed
explanation of his use of lab procedures, his testimony was the
“product of reliable principles and methods.” The court rejected
the defendant’s argument that the expert’s testimony regarding
the pills that were not chemically analyzed was not “based upon
sufficient facts or data” and did not reflect application of “the
principles and methods reliably to the facts of the case.”
Specifically, the defendant pointed to lab rules and regulations
stating that under administrative sampling selection, no inferences
about unanalyzed materials are to be made. The expert testified
however that the lab rules and regulations regarding no inferences
for unanalyzed substances does not apply to pharmaceutically
prepared substances. For other cases involving sampling in drug
testing, see Section II.F.14. below.
State v. Abrams, ___ N.C. App. ___, 789 S.E.2d 863, 864-65
(2016). In this drug case, the trial court did not abuse its discretion
by admitting expert testimony identifying the substance at issue as
marijuana. At trial, Agent Baxter, a forensic scientist with the State
Crime Lab, testified that she examined the substance, conducted
relevant tests, and found that the substance was marijuana. The
court rejected the defendant’s argument that the expert’s
testimony was not “the product of reliable principles and methods”
and that the evidence failed to show that she applied the
principles and methods reliably to the facts of the case. Baxter’s
testimony established that she analyzed the substance in
accordance with State Lab procedures, providing detailed
testimony regarding each step in her process. Specifically,
identifying the substance as marijuana involves the following
steps: separating weighable materials from packaging; recording
the weight; conducting a preliminary analysis, such as a color test;
Criminal Evidence: Expert Testimony − 20
conducting a microscopic examination, looking for identified
characteristics of marijuana (e.g., unique characteristics of the
leaves); and conducting the Duquenois–Levine color test. The
court concluded: “Based on her detailed explanation of the
systematic procedure she employed to identify the substance . . .,
a procedure adopted by the NC Lab specifically to analyze and
identify marijuana, her testimony was clearly the ‘product of
reliable principles and methods’ sufficient to satisfy . . . Rule
702(a).” The court went on to reject the defendant’s argument that
Baxter’s testimony did not establish that she applied the principles
and methods reliably to the facts of the case. Based on Baxter’s
testimony regarding her handling of the sample at issue, the court
held that Baxter’s testimony established that the principles and
methods were applied reliably the substance at issue.
E. Procedural Issues.
1. Preliminary Question of Fact. The admissibility of expert testimony is
determined by the trial court pursuant to Rule 104(a). McGrady, 368 N.C.
at 892. See generally N.C.
R. EVID. 104(a). In determining admissibility,
the trial judge is not bound by the rules of evidence, except those with
respect to privileges. McGrady, 368 N.C. at 892 (quoting N.C.
R. EVID.
104(a)).
To the extent that factual findings are necessary to determine
admissibility, the trial judge acts as the trier of fact. Id. at 892 (citing
Commentary to N.C.
R. EVID. 104(a)). The standard for factual findings is
the greater weight of the evidence Id. at 892–93.
2. Burden of Proof. The proponent of the evidence bears the burden of
establishing that the evidence is admissible. State v. Ward, 364 N.C. 133,
140 (2010) (pre-amendment expert witness case).
3. Flexible Inquiry. Because Rule 702(a) does not mandate any particular
procedure for the court to determine the admissibility of expert testimony,
the trial court has the discretion to determine how to best handle the
matter. Kumho Tire, 526 U.S. at 152 (“The trial court must have the same
kind of latitude in deciding how to test an expert's reliability, and to decide
whether or when special briefing or other proceedings are needed to
investigate reliability, as it enjoys when it decides whether or not that
expert's relevant testimony is reliable.”); see also McGrady, 368 N.C. at
892; State v. Walston, ___ N.C. ___, 798 S.E.2d 741, 747 (2017) (citing
McGrady and noting that “Rule 702 does not mandate any particular
procedural requirements for evaluating expert testimony”); State v.
Abrams, ___ N.C. App. ___, 789 S.E.2d 863, 866 ( 2016) (quoting
McGrady). In simple cases, an appropriate foundation may be laid on
direct examination. McGrady, 368 N.C. at 893. In more complex cases,
the trial court may opt for special briefings, submission of affidavits, voir
dire testimony, or an in limine hearing. Id. Whatever the case, the trial
court “should use a procedure that, given the circumstances of the case,
will secure fairness in administration, elimination of unjustifiable expense
and delay, and promotion of growth and development of the law of
evidence to the end that the truth may be ascertained and proceedings
justly determined.” Id. (quotation omitted).
Criminal Evidence: Expert Testimony − 21
Noting the difficulty a silent record creates for purposes of appeal, a
concurring opinion in one post-McGrady cases suggests:
[B]est practice dictates parties should challenge an
expert's admissibility through a motion in limine. In the
event a trial court delays its ruling on the matter, or in the
event a party fails to raise the challenge until the expert is
called upon at trial, our trial courts should afford parties a
voir dire hearing to examine the witness and submit
evidence into the record, which this Court can review on
appeal.
Abrams, ___ N.C. App. at ___, 789 S.E.2d at 869 (Hunter, J., concurring).
4. Findings of Fact & Conclusion of Law. In McGrady, the North Carolina
Supreme Court stated that the trial court must find the relevant facts
pertaining to admissibility and then, based on these findings, determine
whether the proffered expert testimony meets the rule’s requirements of
qualification, relevance, and reliability. McGrady, 368 N.C. at 892–93.
Although some language in at least one subsequent court of appeals
case suggests that the trial courts are not required to make findings of
fact or conclusions of law regarding the admissibility of expert testimony,
Abrams, ___ N.C. App. at ___, 789 S.E.2d at 868 (Hunter, J., concurring)
(“At the present, trial courts are not required to make findings of fact or
conclusions of law when they accept or reject an expert witness.”), that
same case suggests that the better practice in light of McGrady is to
make such findings and conclusions on the record. Id. at 869 (“[T]he trial
court should identify the Daubert factors and make findings of fact and
conclusions of law, either orally or in writing, as to the expert's
admissibility.”).
5. Informing the Jury of Witness’s Expert Status. Some commentators
and authority from other jurisdictions suggest that it is preferable for the
trial court not to advise the jury that it has found a witness to be an expert,
to avoid undue influence that the jury might place on the witness’s
testimony. See e.g., Advisory Committee Notes to F
ED. R. EVID. 702
(“[T]here is much to be said for a practice that prohibits the use of the
term ‘expert’ by both the parties and the court at trial. Such a practice
ensures that trial courts do not inadvertently put their stamp of authority
on a witness's opinion, and protects against the jury's being overwhelmed
by the so-called ‘experts.’” (quotation omitted)); National Commission on
Forensic Science, Views of the Commission Regarding Judicial Vouching
(June 21, 2016) (“The Commission is of the view that it is improper and
misleading for a trial judge to declare a witness to be an expert in the
presence of the jury.”),
https://www.justice.gov/ncfs/file/880246/download;
United States v. Johnson, 488 F.3d 690, 697-98 (6th Cir. 2007) (agreeing
with decisions that have articulated “good reasons” for not informing the
jury that a witness has been qualified as an expert); Michael H. Graham,
Expert Witness Testimony: Fed. R. Evid. 702-705 Primer; Hypothetical
Question Discretionary Use, 52 No. 5 C
RIM. L. BULL Art. 8 (2016) (“It is
preferable that the court not advise the jury of its determination if it
decides that the witness is in fact qualified as an expert as to a particular
subject matter.”). However, several older North Carolina criminal cases
Criminal Evidence: Expert Testimony − 22
found no error when a trial court determined that a witness was an expert
in the presence of the jury. State v. Frazier, 280 N.C. 181, 197, vacated
on other grounds, 409 U.S. 1004 (1972) (the trial court determined, in the
presence of the jury, that two witnesses were qualified to testify as
experts; stating: “It has never been the general practice in the courts of
this State for the trial judge to excuse the jury from the courtroom when
ruling upon the qualification of a witness to testify as an expert.”); State v.
Edwards, 24 N.C. App. 303, 305 (1974) (citing Frazier and holding that
the trial court did not err by stating, in the presence of the jury, that it
found a medical doctor to be expert witness). Additionally, N.C. Pattern
Instruction – Crim 104.94 (Testimony of Expert Witness) expressly
informs the jury of the witness’s status as an expert and at least one
unpublished case indicates that the better practice is to give this
instruction. State v. Dunn, 220 N.C. App. 524, *9 (2012) (unpublished)
(holding that no error occurred when the trial court failed to give the
pattern instruction but noting: “the better practice is for the trial court to
specifically instruct the jury on expert testimony when an expert has
testified at trial”); see generally State v. Prevatte, 356 N.C. 178, 224
(2002) (noting that the court has approved of the pattern instruction).
F. Particular Types of Experts. Several common types of expertise are explored
in the sections immediately below. This Chapter does not attempt to present an
exhaustive evaluation of these areas of expert testimony. Rather, it provides the
trial judge with an overview of the current state of North Carolina law with respect
to each category and alerts the trial court to potential issues. As science and
technology evolve, new tests and analyses may be developed providing a better
understanding as to the strengths and weakness of tests and analyses currently
being done and resulting in new tests and analyses. Either or both developments
may impact existing law.
When discussing certain forensic science disciplines, this Chapter cites
the following report: P
RESIDENT’S COUNCIL OF ADVISORS ON SCIENCE AND
TECHNOLOGY, FORENSIC SCIENCE IN CRIMINAL COURTS: ENSURING SCIENTIFIC
VALIDITY OF FEATURE-COMPARISON METHODS (2016) [hereinafter PCAST
REPORT],
https://obamawhitehouse.archives.gov/sites/default/files/microsites/ostp/PCAST/
pcast_forensic_science_report_final.pdf. This report is cited because it is the
most recent comprehensive evaluation of the relevant forensic science
disciplines. Although some, such as the National Association of Criminal Defense
Lawyers, have applauded that report, it was not adopted by the Department of
Justice and others, including the National District Attorneys Association, have
been critical of it or have challenged it. Jack D. Roady, The PCAST Report: A
Review and Moving Forward−A Prosecutor’s Perspective, C
RIMINAL JUSTICE,
Summer 2017, at 9 (discussing the reaction to the report by prosecutors, defense
attorneys, and the forensic science community).
For discussion of the proper scope of expert testimony in sexual assault
cases, see
Evidence Issues Criminal Cases Involving Child Victims and Child
Witnesses in this Benchbook.
1. Use of Force & Self-Defense Experts. Although use of force and self-
defense experts are used in North Carolina criminal trials, see, e.g., State
v. McDowell, 215 N.C. App. 184, 189 (2011) (noting that Mr. Cloutier
testified as an expert in “use-of-force science” and self-defense tactics),
Criminal Evidence: Expert Testimony − 23
few published cases directly address the admissibility of such evidence.
One case that does is State v. McGrady, 368 N.C. 880 (2016), decided
under amended Rule 702(a) and the Daubert standard. In McGrady, the
North Carolina Supreme Court held that the trial court did not abuse its
discretion by excluding testimony by a defense proffered expert. At trial
the defendant sought to call Dave Cloutier as an expert in “the science of
the use of force” Id. at 883. Cloutier was proffered to testify on three
topics:
(1) that, based on the “pre-attack cues” and “use of force
variables” present in the interaction between defendant and the
victim, the defendant's use of force was a reasonable response to
an imminent, deadly assault that the defendant perceived;
(2) that defendant's actions and testimony are consistent with
those of someone experiencing the sympathetic nervous system's
“fight or flight” response; and
(3) that reaction times can explain why some of defendant's
defensive shots hit the victim in the back.
Id. at 894. The Supreme Court held that the trial court did not abuse its
discretion in excluding the expert’s testimony about “pre-attack cues” and
“use of force variables” on grounds that it was not relevant. Id. Cloutier’s
report indicated that pre-attack cues are actions “exhibited by an
aggressor as a possible precursor to an actual attack,” and include
“actions consistent with an assault, actions consistent with retrieving a
weapon, threats, display of a weapon, employment of a weapon, profanity
and innumerable others.” Id. According to Cloutier, “use of force
variables” include additional circumstances and events that influence a
person’s decision about the type and degree of force necessary to repel a
threat, such as age, gender, size, and number of individuals involved; the
number and type of weapons present; and environmental factors. Id. at
895. The court found this this testimony would not assist the jury because
these matters were within the juror’s common knowledge. Id.
Next, the McGrady court found that the trial court did not abuse its
discretion by concluding that Cloutier was not qualified to offer expert
testimony on the stress responses of the sympathetic nervous system. Id.
Cloutier’s report stated that an instinctive survival response to fear “can
activate the body's sympathetic nervous system” and the “‘fight or flight’
response.” Id. He indicated that the defendant's perception of an
impending attack would cause an adrenalin surge “activat[ing] instinctive,
powerful and uncontrollable survival responses.” Id. He further maintained
that this nervous system response causes “perceptual narrowing,”
focusing a person's attention on the threat and leading to a loss of
peripheral vision and other changes in visual perception. Id. According to
Cloutier, this nervous system response also can cause “fragmented
memory,” or an inability to recall specific events related to the threatening
encounter. Id. at 895-96. The court held that it was not an abuse of
discretion to require “a witness who intended to testify about the functions
of an organ system to have some formal medical training.” Id. at 896.
Finally, the court held that the trial court did not abuse its
discretion by finding that the expert’s testimony regarding reaction times
Criminal Evidence: Expert Testimony − 24
was unreliable. Id. at 897. This testimony was offered to rebut any
assumption in the jurors' minds that the defendant could not have acted
defensively if he shot the victim in the back. Id. Because the expert
testified on voir dire that he interviewed the defendant and other
witnesses; reviewed interviews of the defendant and a witness, the case
file, and physical evidence collected by the Sherriff's Department; and
visited the location of the incident, the expert’s testimony satisfied the
“sufficient facts or data” requirement in Rule 702(a)(1). Id. However, the
expert based his testimony about average reaction times on statistics
from two studies, but did not know whether or not those studies reported
error rates and, if so, what those error rates were. Thus, a trial judge
could reasonably conclude that the expert’s degree of unfamiliarity with
the studies rendered unreliable his testimony about them and the
conclusions about the case that he drew from them. Id. at 898-99. Also,
while the expert established that a disability could affect reaction time, he
failed to account for the defendant’s back injury in his analysis. The court
found that this failure relates both to the sufficiency of the facts and data
relied upon and to whether the expert applied his own methodology
reliably in this case. Id.at 899.
2. DNA Identification Evidence. “Deoxyribonucleic acid, or DNA, is a
molecule that encodes the genetic information in all living organisms.”
F
EDERAL JUDICIAL CENTER & NATIONAL RESEARCH COUNCIL OF THE
NATIONAL ACADEMIES, REFERENCE MANUAL ON SCIENTIFIC EVIDENCE 131
(3d ed. 2011) [hereinafter R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE],
https://www.fjc.gov/sites/default/files/2015/SciMan3D01.pdf. “DNA
analysis involves comparing DNA profiles from different samples to see if
a known sample may have been the source of an evidentiary sample.”
PCAST
REPORT at 69. It is important to understand, however, that the
term “DNA testing” encompasses different kinds of testing methods,
different sources of bodily material, and differing statistical means of
assessing the significance of a match, all of which has changed and likely
will continue to change as science and technology advance. 4 D
AVID L.
FAIGMAN ET AL., MODERN SCIENTIFIC EVIDENCE: THE LAW AND SCIENCE OF
EXPERT TESTIMONY 157 (2016-17 ed.) [hereinafter MODERN SCIENTIFIC
EVIDENCE]. Although some forms of DNA evidence are now admissible in
all jurisdictions, there are many types of forensic DNA analysis, and more
are being developed. R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE at
131. Questions of admissibility will continue to arise as advancing
methods of analysis and novel applications of established methods are
introduced. Id.
This Chapter does not attempt to explain the wide variety of DNA
testing that has been and currently is being done in forensic labs and
potential issues regarding that testing. For a discussion of the history of
DNA evidence, the types of scientific expertise that go into the analysis of
DNA samples, the scientific principles behind DNA typing, issues
regarding sample quantity and quality and laboratory performance, issues
in the interpretation of laboratory results, special issues in human DNA
testing for identification, and forensic analysis of nonhuman DNA, see
R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE at 131-210. For the PCAST
REPORT’s assessment of DNA testing using single source samples,
Criminal Evidence: Expert Testimony − 25
simple mixture samples, and complex mixture samples, see PCAST
REPORT at 69-83.
Although expert testimony regarding DNA analysis repeatedly has
been found to be admissible in North Carolina prior to the 2011
amendments to Rule 702, see, e.g., State v. Pennington, 327 N.C. 89,
98-101 (1990), there do not appear to be any published North Carolina
cases directly assessing any form of DNA testing under the new Daubert
standard. Courts in other jurisdictions have allowed expert testimony
regarding the polymerase chain reaction and short tandem repeats
method of DNA typing under the Daubert standard. See generally 33A
F
ED. PROC., L. ED. § 80:226 (“Applying the Daubert test, expert DNA
evidence has generally been found to be admissible. More specifically,
based on overwhelming scientific and forensic acceptance, as well as
acceptance by the vast majority of courts, the polymerase chain reaction
and short tandem repeats (PCR/STR) method of DNA typing has been
held reliable and admissible under the rule governing expert opinion and
Daubert.”).
Separate from Daubert standard issues, expert testimony that
amounts to a “prosecutor’s fallacy” is improper. “The prosecutor's fallacy
is the assumption that the random match probability is the same as the
probability that the defendant was not the source of the DNA sample.”
McDaniel v. Brown, 558 U.S. 120, 128 (2010). The U.S. Supreme Court
has explained:
In other words, if a juror is told the probability a member of
the general population would share the same DNA is 1 in
10,000 (random match probability), and he takes that to
mean there is only a 1 in 10,000 chance that someone
other than the defendant is the source of the DNA found at
the crime scene (source probability), then he has
succumbed to the prosecutor's fallacy. It is . . . error to
equate source probability with probability of guilt, unless
there is no explanation other than guilt for a person to be
the source of crime-scene DNA. This faulty reasoning may
result in an erroneous statement that, based on a random
match probability of 1 in 10,000, there is a .01% chance
the defendant is innocent or a 99.99% chance the
defendant is guilty.
Id.; see also State v. Ragland, 226 N.C. App. 547, 558-60 (2013) (the
State’s expert improperly relied on the prosecutor’s fallacy, erroneously
assuming that the random match probability was the same as the
probability that the defendant was not the source of the DNA sample; this
testimony was inadmissible).
3. Bite Mark Identification Evidence. Bite mark analysis “typically involves
examining marks left on a victim or an object . . . and comparing those
marks with dental impressions taken from a suspect.” PCAST
REPORT at
83. For a discussion of the technique involved with this type of analysis,
see R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE at 103-08.
North Carolina cases decided prior to the 2011 amendment to
Rule 702 have held that the trial court did not abuse its discretion by
Criminal Evidence: Expert Testimony − 26
admitting expert bite mark identification testimony. See, e.g., State v.
Temple, 302 N.C. 1, 10-13 (1981) (deciding an issue of first impression,
the court held that the trial court properly admitted expert testimony that
bite marks appearing on the victim's body were made by the defendant's
teeth); State v. Green, 305 N.C. 463, 470-72 (1982) (citing Temple, the
court held that the trial court properly allowed an expert to testify that a
bite mark on the victim’s arm had been made by the defendant).
However, there do not appear to be any published North Carolina cases
analyzing bite mark identification analysis under the new Daubert
standard. Research revealed only one North Carolina bite mark case
decided under amended Rule 702(a), but that case did not deal with bite
mark identification evidence. See State v. Ford, ___ N.C. App. ___, 782
S.E.2d 98, 107-08 (2016) (trial court did not commit plain error by
allowing the State’s forensic pathology expert to opine that victim’s death
was due to bites from a dog).
Although questions have been raised about the validity of bite
mark analysis, see, e.g., PCAST
REPORT at 83-87 (“[B]itemark analysis
does not meet the scientific standards for foundational validity, and is far
from meeting such standards. To the contrary, available scientific
evidence strongly suggests that examiners cannot consistently agree on
whether an injury is a human bitemark and cannot identify the source of
bite mark with reasonable accuracy.”), courts in other jurisdictions have
continued to admit the evidence. R
EFERENCE MANUAL ON SCIENTIFIC
EVIDENCE at 112.
4. Fingerprint Identification Evidence. Fingerprint identification evidence
refers to the use of fingerprints as a means of personal identification, e.g.,
that fingerprints found at the murder scene match fingerprints on file for
the defendant. For a discussion of the methodology used in fingerprint
identification analysis, see R
EFERENCE MANUAL OF SCIENTIFIC EVIDENCE
at 73-76, and PCAST
REPORT at 88-91.
Expert testimony regarding fingerprint analysis has been
admissible in North Carolina for many years under the state’s pre-Daubert
standards. State v. Irick, 291 N.C. 480, 488-89 (1977); see also State v.
Hoff, 224 N.C. App. 155, 163 (2012) (citing Irick and noting “our Supreme
Court's long-standing acceptance of the reliability of fingerprint
evidence”); State v. Parks, 147 N.C. App. 485, 490-91 (2001) (no abuse
of discretion in admitting officer’s expert testimony in fingerprint analysis
given that the state Supreme Court has “recognized that fingerprinting is
an established and scientifically reliable method of identification”). There
do not appear to be any published North Carolina criminal cases
evaluating fingerprint analysis under the Daubert standard. Courts in
other jurisdictions have—for the most part—held such testimony to be
sufficiently reliable expertise under Daubert. See R
EFERENCE MANUAL ON
SCIENTIFIC EVIDENCE at 82-83. The Fourth Circuit is among the courts to
have found fingerprint evidence sufficiently reliable under Daubert. United
States v. Crisp, 324 F.3d 261, 266-69 (4th Cir. 2003) (citing other circuit
courts that have held similarly).
For a discussion of the empirical record regarding this type of
identification, see R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE at 76-81,
and PCAST
REPORT at 91-100. For an assessment as to the foundational
validity and validity as applied of fingerprint evidence, see PCAST
Criminal Evidence: Expert Testimony − 27
R
EPORT at 101-103 (finding that “latent fingerprint analysis is a
foundationally valid subjective methodology” and that “[c]onclusions of a
proposed identification may be scientifically valid, provided that they are
accompanied by accurate information about limitations on the reliability of
the conclusion”; going on to identify a number of issues regarding validity
as applied).
5. Firearm Identification. In firearms identification analysis, sometimes
called “ballistics,” “examiners attempt to determine whether ammunition is
or is not associated with a specific firearm based on marks produced by
guns on the ammunition.” PCAST
REPORT at 104. For a discussion of the
methodology of this this analysis, see R
EFERENCE MANUAL ON SCIENTIFIC
EVIDENCE at 91-97, and PCAST REPORT at 104.
Pre-Daubert North Carolina cases had allowed this type of expert
testimony. See, e.g., State v. Britt, 217 N.C. App. 309, 314 (2011)
(“Courts in North Carolina have upheld the admission of expert testimony
on firearm toolmark identification for decades.”). There do not appear to
be any published North Carolina cases applying the new Daubert
standard to this type of evidence.
Although testimony by firearms experts is widely admitted
nationwide with little judicial scrutiny, provided the expert is qualified, 3
BARBARA E. BERGMAN ET AL., WHARTON'S CRIMINAL EVIDENCE § 13:59
(15th ed.) [hereinafter W
HARTON’S CRIMINAL EVIDENCE] (but noting: “Little
justification appears to warrant such a cavalier attitude toward this
testimony.”), some post-Daubert decisions have excluded or limited
expert firearms analysis testimony. See R
EFERENCE MANUAL ON
SCIENTIFIC EVIDENCE at 101-02 (discussing cases). Questions have been
raised about the foundational validity of firearms analysis. See PCAST
REPORT at 112 (“PCAST finds that firearms analysis currently falls short
of the criteria for foundational validity, because there is only a single
appropriately designed study to measure validity and estimate reliability.
The scientific criteria for foundational validity require more than one such
study, to demonstrate reproducibility.”); R
EFERENCE MANUAL ON
SCIENTIFIC EVIDENCE at 97-100 (discussing the empirical record on this
type of evidence and noting, in part: “The issue of the adequacy of the
empirical basis of firearms identification expertise remains in dispute . . .
.”). Additionally, it has been suggested that if firearms analysis is allowed
in court, validity as applied requires that the expert has undergone
rigorous proficiency testing and that certain disclosures be made. PCAST
R
EPORT at 113.
6. Blood Alcohol Extrapolation. “Retrograde extrapolation is a
mathematical analysis in which a known blood alcohol test result is used
to determine what an individual’s blood alcohol level would have been at
a specified earlier time.” State v. Cook, 362 N.C. 285, 288 (2008).The
analysis determines the prior blood alcohol level based on (1) the time
elapsed between the earlier event, such as a vehicle crash, and the blood
test, and (2) the rate of elimination of alcohol from the subject's blood
during the time between the event and the test. Id.
North Carolina cases decided under both Howerton and Daubert
have held that the trial court does not abuse its discretion by admitting
expert testimony regarding blood alcohol extrapolation. See, e.g., State v.
Turbyfill, ___ N.C. App.___, 776 S.E.2d 249, 255-58 (2015) (applying
Criminal Evidence: Expert Testimony − 28
Daubert and holding that testimony by the State’s expert “confirmed that
blood alcohol extrapolation is a scientifically valid field, which principles
have been tested, subjected to peer review and publication, and
undisputedly accepted in the scientific community and in our courts”);
State v. Green, 209 N.C. App. 669, 677-680 (2011) (same, under earlier
Howerton standard).
However, for expert testimony on retrograde extrapolation to be
admissible it must be based on sufficiently reliable data and a reliable
method of proof. Faulty assumptions in the expert’s application of
retrograde extrapolation analysis can render the expert testimony
inadmissible. Compare State v. Babich, ___ N.C. App. ___, 797 S.E.2d
359, 361-364 (2017) (the trial court erred by admitting retrograde
extrapolation expert testimony where the expert assumed that the
defendant was in a post-absorptive state at the time of the stop (meaning
that alcohol was no longer entering the defendant’s bloodstream and thus
her blood alcohol level was declining) but there were no facts to support
this assumption; reasoning that such testimony was inadmissible “as a
matter of law” because it failed Daubert's “fit” test in that the expert's
analysis was not properly tied to the facts of the case; going on to hold:
“[W]hen an expert witness offers a retrograde extrapolation opinion based
on an assumption that the defendant is in a post-absorptive . . . state, that
assumption must be based on at least some underlying facts to support
that assumption. This might come from the defendant's own statements
during the initial stop, from the arresting officer's observations, from other
witnesses, or from circumstantial evidence that offers a plausible timeline
for the defendant's consumption of alcohol.”), and State v. Davis, 208
N.C. App. 26, 31-35 (2010) (holding, under the earlier and more lenient
Howerton standard that the trial court committed reversible error by
allowing expert Paul Glover to testify to the defendant’s blood-alcohol
level based on retrograde extrapolation where the alcohol concentration
upon which Glover based the extrapolation was estimated to be .02
based on the fact that an officer smelled alcohol on the defendant’s
breath more than ten hours after the incident; Glover’s “odor analysis”
was not a sufficiently reliable method of proof), with State v. Green, 209
N.C. App. 669, 677-80 (2011) (holding, under the earlier and more lenient
Howerton standard that the trial court did not abuse its discretion by
allowing expert Paul Glover to testify regarding retrograde extrapolation
notwithstanding the defendant’s argument that Glover’s testimony was
based on impermissible factual assumptions regarding the amount of
wine in the defendant's glass and when it was consumed).
7. Blood Spatter Analysis. Blood spatter analysis, sometimes called blood
spatter interpretation or bloodstain analysis, is a forensic tool in which
stains of blood at a crime scene are examined to provide information
about the incident, such as where the victim was killed. For the purposes
of this discussion, blood spatter analysis includes the process of
examining blood that has struck a surface, and applying knowledge
regarding the characteristics of blood and the shapes or patterns made by
its impact, in order to determine things like the direction, angle, and speed
of its flight prior to impact, and, ultimately, to assist in reconstructing
events occurring in connection with an alleged crime. See generally
Danny R. Veilleux, Admissibility, in Criminal Prosecution, of Expert
Criminal Evidence: Expert Testimony − 29
Opinion Evidence as to “Blood Splatter” Interpretation, 9 A.L.R.5th 369
(originally published 1993) (discussing the admissibility of evidence so
described). For more information about the history of bloodstain analysis
and the biology, physics and mathematics associated with it, see Aaron
D. Gopen & Edward J. Imwinkelried, Bloodstain Pattern Analysis
Revisited, 45 No. 3 C
RIM. L. BULL. ART. 7 (2009) [hereinafter Bloodstain
Pattern Analysis Revisited].
In cases decided under the old Howerton standard, North Carolina
courts have found bloodstain analysis to be a sufficiently reliable area for
expert testimony. See, e.g., State v. Goode, 341 N.C. 513, 530-31 (1995)
(rejecting the defendant’s argument that bloodstain pattern interpretation
has not been established as a scientifically reliable field; also rejecting the
defendant’s argument that Agent Duane Deaver did not have sufficient
qualifications to testify as an expert in the field); see also State v. Morgan,
359 N.C. 131, 160 (2004) (citing Goode for that proposition, although it
was not an issue in that case); State v. Bruton, 165 N.C. App. 801, 809
(2004) (citing Goode and holding that the trial court did not err by allowing
an expert in forensic serology to testify regarding the nature of blood
spatter over the defendant’s challenge to her qualifications as an expert).
There do not appear to be any North Carolina cases addressing
the admissibility of this evidence under the Daubert standard. For a
discussion of how this evidence is handled in other jurisdictions, see 9
A.L.R.5th 369 and Bloodstain Pattern Analysis Revisited, supra p. 28.
8. Fiber Analysis. In criminal cases, expert testimony may be offered to
show that certain fibers do or do not “match”, typically in the context of
proving or disproving that the suspect had contact with a particular person
or place. This section refers to this sort of testimony as fiber analysis.
In pre-Daubert North Carolina cases, fiber analysis testimony has
been found to be admissible. See, e.g., State v. Vestal, 278 N.C. 561,
593–94 (1971) (no error to allow an expert in the field of analyzing and
comparing fibers to testify “concerning the similarity of the drapes found in
the defendant's warehouse with that found upon the body”). There do not
appear to be any North Carolina cases analyzing this evidence under the
Daubert standard. Some have raised questions about whether fiber
analysis satisfies the Daubert standard. See, e.g, 4 M
ODERN SCIENTIFIC
EVIDENCE at 114 (“The validity of fiber identification techniques is
susceptible of objective testing, although this has not been accomplished
on a scale and in such a manner as to satisfy Daubert. The error rate of
fiber examination is unknown. The validity of the interpretation of the
significance of a match in fiber evidence has not been subjected to
systematic testing of the sort countenanced by Daubert.”).
9. Hair Analysis. “Forensic hair examination is a process by which
examiners compare microscopic features of hair to determine whether a
particular person may be the source of a questioned hair.” PCAST
REPORT at 118. For a discussion of the technique used in this type of
analysis, see R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE at 113-14.
Several North Carolina cases decided prior to the 2011
amendment to Rule 702 approved of admitting expert testimony regarding
hair analysis. See, e.g., State v. Green, 305 N.C. 463, 470 (1982) (“This
Court has previously approved of testimony similar to that employed in
the case before us and we are not inclined to reverse that holding.”
Criminal Evidence: Expert Testimony − 30
(citation omitted)); State v. Vestal, 278 N.C. 561, 593–94 (1971) (no error
to allow an expert in the field of analyzing and comparing hair to testify
regarding the similarity of hairs found in a warehouse and trunk of the
defendant's automobile with hairs taken from the head of the victim’s
body); State v. McCord, 140 N.C. App. 634, 659 (2000) (the trial court did
not abuse its discretion by admitting expert testimony that a pubic hair
taken from the victim was microscopically consistent with a known sample
of defendant’s pubic hair; “because the comparison of hair samples has
been accepted as reliable scientific methodology in this State, the trial
court properly allowed [the analyst] to testify regarding the results of his
testing”); State v. Suddreth, 105 N.C. App. 122, 132 (1992) (“Our courts
have liberally permitted the introduction of expert testimony as to hair
analysis when relevant to aid in establishing the identity of the
perpetrator.”).
However, case law suggests that hair analysis is conclusive, if at
all, only as to negative identify—that is, to exclude a suspect. State v.
Stallings, 77 N.C. App. 189, 191 (1985). For example, if the hair in
question is blonde, straight, and 12 inches long, an individual with black,
curly, two inch long hair can be excluded as the source of the sample. 4
M
ODERN SCIENTIFIC EVIDENCE at 111. Cases also hold that microscopic
hair analysis evidence is insufficient on its own to positively identify a
defendant as the perpetrator. Stallings, 77 N.C. App. at 191 (hair analysis
“must be combined with other substantial evidence to take a case to the
jury”); State v. Bridges, 107 N.C. App. 668, 671 (1992) (citing Stallings
and stating that it “may not be used to positively identify a defendant as
the perpetrator of a crime”), aff'd per curiam, 333 N.C. 572 (1993); State
v. Faircloth, 99 N.C. App. 685, 692 (1990) (same). As the court stated in
Stallings: “Unlike fingerprint evidence . . . comparative microscopy of hair
is not accepted as reliable for positively identifying individuals. Rather, it
serves to exclude classes of individuals from consideration and is
conclusive, if at all, only to negative identity.” Stallings, 77 N.C. App. at
191.
Additionally, some pre-Daubert cases limit the scope of a hair
analysis expert’s testimony. See Bridges, 107 N.C. App. at 671-75 (the
trial court erred by admitting the expert’s testimony about the statistical
probability of two Caucasians having indistinguishable head hair because
there was insufficient foundation for this testimony); Faircloth, 99 N.C.
App. at 690-92 (the trial court erred by allowing a hair examination and
identification expert to testify that it was “improbable” that pubic hairs
obtained from the victim’s body and from a sheet on the victim’s bed
came from an individual other than the defendant and that it would be
“impossible” for another person whose hair was consistent with the
defendant’s to have come in contact with the victim’s bedsheets).
There do not appear to be any North Carolina cases ruling on the
admissibility of this evidence under the Daubert standard. It should be
noted that in recent years, serious questions have been raised about the
validity of forensic hair analysis and associated expert testimony. See,
e.g., Spencer S. Hsu, FBI Admits Flaws in Hair Analysis Over Decades,
T
HE WASHINGTON POST, April 18, 2015 (reporting that “[t]he Justice
Department and FBI have formally acknowledged that nearly every
examiner in an elite FBI forensic unit gave flawed testimony in almost all
Criminal Evidence: Expert Testimony − 31
trials in which they offered evidence against criminal defendants over
more than a two-decade period before 2000”); 4 M
ODERN SCIENTIFIC
EVIDENCE at 112 (“The validity of hair evidence is susceptible of objective
testing, although this has not been accomplished on a scale and in such a
manner as to satisfy Daubert. The error rate of hair examination is
unknown.”); PCAST
REPORT 118-122 (finding that materials provided by
the Department of Justice “do not provide a scientific basis for concluding
that microscopic hair examination is a valid and reliable process”).
Although many cases have continued to admit hair analysis post-Daubert,
that is not universally true and “growing judicial support” for the view that
this type of analysis is unreliable has been noted. R
EFERENCE MANUAL ON
SCIENTIFIC EVIDENCE at 119.
10. Shoe Print Analysis. “Footwear analysis is a process that typically
involves comparing a known object, such as a shoe, to a complete or
partial impression found at a crime scene, to assess whether the object is
likely to be the source of the impression.” PCAST
REPORT at 114.
Although some North Carolina cases state that a non-expert may
testify to shoe print comparisons, see, e.g., State v. General, 91 N.C.
App. 375, 379 (1988) (citing State v. Jackson, 302 N.C. 101, 107 (1981));
State v. Plowden, 65 N.C. App. 408, 410 (1983) (same), trial courts have
admitted expert testimony on this topic. See, e.g., State v. Williams, 308
N.C. 47, 60–61 (1983) (noting that an SBI Agent was accepted as an
expert witness and testified extensively concerning the unique
characteristics of the tread on the shoes taken from the defendant and
the shoe prints found at the scene of the crime). However, there do not
appear to be any North Carolina cases examining the admissibility of this
evidence under the Daubert standard. Although federal courts have
admitted expert shoe print testimony under Daubert, see, e.g., United
States v. Ford, 481 F.3d 215, 217-21 (3d Cir. 2007); United States v.
Allen, 390 F.3d 944, 949-50 (7th Cir. 2004); United States v. Mahone,
328 F. Supp. 2d 77, 90-92 (D. Me. 2004), aff'd, 453 F.3d 68 (1st Cir.
2006), questions have been raised about the foundational validity of this
analysis. See PCAST
REPORT at 117 (concluding that “there are no
appropriate empirical studies to support the foundational validity of
footwear analysis to associate shoeprints with particular shoes based on
specific identifying marks (sometimes called []randomly acquired
characteristics). Such conclusions are unsupported by any meaningful
evidence or estimates of their accuracy and thus are not scientifically
valid.”).
11. Handwriting Analysis. Handwriting analysis seeks to determine the
authorship of a piece of writing by examining the way in which the letters
are inscribed, shaped and joined and comparing it to samples by a known
author. 4 M
ODERN SCIENTIFIC EVIDENCE at 561-62. For a discussion of the
technique used in this type of analysis and the empirical record regarding
its validity, see R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE at 83-89.
North Carolina civil cases decided before the amendment to Rule
702(a) upheld admission of expert testimony regarding handwriting
analysis, see, e.g., Taylor v. Abernethy, 149 N.C. App. 263, 270-74
(2002) (trial court erred by refusing to allow a handwriting expert to give
his opinion regarding the validity of a signature on a contract). There do
not appear to be any published North Carolina cases on point after North
Criminal Evidence: Expert Testimony − 32
Carolina became a Daubert state. In other jurisdictions, there is a three-
way split of authority regarding this type of expert testimony:
The majority of courts permit examiners to express
individuation opinions. As one court noted, “all six circuits
that have addressed the admissibility of handwriting expert
[testimony] . . . [have] determined that it can satisfy the
reliability threshold” for nonscientific expertise. In contrast,
several courts have excluded expert testimony, although
one involved handprinting and another Japanese
handprinting. Many district courts have endorsed a third
view. These courts limit the reach of the examiner’s
opinion, permitting expert testimony about similarities and
dissimilarities between exemplars but not an ultimate
conclusion that the defendant was the author (“common
authorship” opinion) of the questioned document. The
expert is allowed to testify about “the specific similarities
and idiosyncrasies between the known writings and the
questioned writings, as well as testimony regarding, for
example, how frequently or infrequently in his experience,
[the expert] has seen a particular idiosyncrasy.” As the
justification for this limitation, these courts often state that
the examiners’ claimed ability to individuate lacks
“empirical support.”
R
EFERENCE MANUAL ON SCIENTIFIC EVIDENCE at 90. The Fourth Circuit is
among the courts that have held that expert handwriting testimony passes
muster under Daubert. See United States v. Crisp, 324 F.3d 261, 270-71
& n.5 (4th Cir. 2003) (deciding the issue as a matter of first impression;
citing circuit court decisions that have held similarly but noting that some
district courts recently had held that handwriting analysis does not meet
the Daubert standard).
12. Horizontal Gaze Nystagmus (HGN). A leading treatise explains
horizontal gaze nystagmus as follows:
Nystagmus is an involuntary rapid movement of the
eyeball, which may be horizontal, vertical or rotary. An
inability of the eyes to maintain visual fixation as they are
turned from side to side (in other words, jerking or
bouncing) is known as horizontal gaze nystagmus, or
HGN. Proponents of HGN tests believe that alcohol and
drug use increases the frequency and amplitude of HGN
and cause it to occur at a smaller angle of deviation from
forward. Nystagmus tests are not done in a laboratory, but
rather are given by police officers in the field or in a police
station subsequent to arrest. The results of an HGN test
are frequently introduced as part of the state’s case in
drunk driving prosecutions and they also may be used
when an individual is suspected to be under the influence
of some other substance . . . .
Criminal Evidence: Expert Testimony − 33
5 M
ODERN SCIENTIFIC EVIDENCE at 459 (quotation omitted).
Rule 702(a1) provides that a witness qualified under Rule 702(a)
“and with proper foundation, may give expert testimony solely on the
issue of impairment and not on the issue of specific alcohol concentration
level relating to . . . [t]he results of a [HGN] Test when the test is
administered by a person who has successfully completed training in
HGN.” This subsection obviates the State’s need to prove that the
horizontal gaze nystagmus testing method is sufficiently reliable. State v.
Younts, ___ N.C. App. ___, ___ S.E.2d ___ (July 18, 2017) (post-
amendment case); State v. Smart, 195 N.C. App. 752, 755-56 (2009)
(pre-amendment case); see also State v. Godwin, ___ N.C. ___, 800
S.E.2d 47 (2017) (“Furthermore, with the 2006 amendment to Rule 702,
our General Assembly clearly signaled that the results of the HGN test
are sufficiently reliable to be admitted into the courts of this State.”).
Whether there are due process limits on the legislature’s ability to declare
certain expert testimony to be reliable is beyond the scope of this
Chapter.
According to the text of the Rule 702(a1) HGN expert testimony is
admissible when the witness is qualified under Rule 702(a) and a proper
foundation is laid. N.C.
R. EVID. 702(a1); see also State v. Torrence, ___
N.C. App. ___, 786 S.E.2d 40, 42 (2016) (“[I]f an officer is going to testify
on the issue of impairment relating to the results of an HGN test, the
officer must be qualified as an expert witness under Rule 702(a) and
establish proper foundation.”). Although the better practice may be to do
so, the court is not required to expressly determine that the witness is so
qualified; such a determination can be implied from the record. Godwin,
___ N.C. ___, 800 S.E.2d 47, 52-53 (2017) (holding that the trial court
implicitly found that the witness was qualified to testify but noting that “the
appellate division's ability to review the trial court's oral order would have
benefited from the inclusion of additional facts supporting its
determination that [the] Officer . . . was qualified to testify as an expert
regarding his observations of defendant's performance during the HGN
test”). Presumably a proper foundation would include establishing that the
test was performed according to accepted protocol.
Once the witness is qualified and a proper foundation is laid, the
witness may give expert testimony regarding the HGN test results,
subject to the additional limitations in subsection (a1), namely, the
witness may testify solely on the issue of impairment and not on the issue
of specific alcohol concentration. N.C.
R. EVID. 702(a1); see also
Torrence, ___ N.C. App. ___, 786 S.E.2d at 43 (prejudicial error where
officer testified to a specific alcohol concentration); see also State v.
Turbyfill, ___ N.C. App. ___, 776 S.E.2d 249, 259 (2015) (officer’s
testimony as to the defendant’s BAC appears to have violated Rule
702(a1)) but the error did not have a probable impact on the verdict).
13. Eyewitness Identification Experts. Several North Carolina appellate
decisions have found no abuse of discretion where the trial court
excluded testimony regarding reliability of eyewitness identification
evidence when the expert’s testimony did not relate to the facts of the
particular case, see, e.g., State v. McLean, 183 N.C. App. 429, 435
(2007) (expert did not interview the witnesses, visit the crime scene, or
listen to court testimony), or because its prejudicial value outweighed its
Criminal Evidence: Expert Testimony − 34
probative value under Rule 403, see, e.g., McLean, 183 N.C. App. at 435
(no abuse of discretion where the trial court found that the value of the
evidence was “marginally weak” and that it would confuse the jury,
unnecessarily delay the proceeding, and would not significantly help the
jury); State v. Cotton, 99 N.C. App. 615, 621-22 (1990), aff'd, 329 N.C.
764 (1991) (similar). However, a recent decision of the North Carolina
Supreme Court suggests that it is not proper to exclude such testimony
simply because the expert has not interviewed or examined the witness.
State v. Walston, ___ N.C. ___, 798 S.E.2d 741, 747 (2017) (holding that
the trial court did not abuse its discretion by excluding testimony from a
defense expert regarding repressed memory and the suggestibility of
memory; the court clarified that to be admissible, the expert need not
have examined or interviewed the witness, noting: “[s]uch a requirement
would create a troubling predicament given that defendants do not have
the ability to compel the State's witnesses to be evaluated by defense
experts”).
The United States Supreme Court has noted that “some States . .
. permit defendants to present expert testimony on the hazards of
eyewitness identification evidence.” Perry v. New Hampshire, 565 U.S.
228, 247 (2012) (quoting State v. Clopten, 223 P.3d 1103, 1113 (“We
expect … that in cases involving eyewitness identification of strangers or
near-strangers, trial courts will routinely admit expert testimony [on the
dangers of such evidence].”)). Commentators have noted that while
eyewitness testimony identifying the perpetrator of the crime is often
important evidence for the State in a criminal trial, such testimony has
been found to be erroneous in some cases. 2 M
ODERN SCIENTIFIC
EVIDENCE at 578 (noting that in cases where DNA evidence exonerated
defendants, eyewitness evidence identified the defendant as the
perpetrator). They argue that expert testimony may help explain why such
testimony can be wrong, by, for example, describing the impact of
“estimator variables” (factors that might affect the eyewitnesses ability to
perceive the events accurately, e.g., lighting conditions, or to describe
accurately what was perceived) and “system variables” (factors outside
the control of the eyewitness, such as the suggestiveness of a photo
array). Id.
14. Drug Identification & Quantity.
a. Chemical Analysis Generally Required. In State v. Ward, 364
N.C. 133 (2010), a case decided under the more lenient Howerton
standard, the North Carolina Supreme Court held that “[u]nless
the State establishes . . . that another method of identification is
sufficient to establish the identity of the controlled substance
beyond a reasonable doubt, some form of scientifically valid
chemical analysis is required” to identify a substance as a
controlled substance. Id. at 147.
At least one post-Ward North Carolina case applying the
Daubert standard has found no error when an expert testified to
drug identification based on a chemical analysis. See, e.g., State
v. Abrams, ___ N.C. App. ___, 789 S.E.2d 863, 865-67 (2016)
(expert testified that the substance was marijuana based on a
chemical analysis; the expert’s testimony was “clearly” the product
of reliable principles and methods and her testimony established
Criminal Evidence: Expert Testimony − 35
that she applied those principles and methods reliability to the
facts of the case).
b. Visual Identification. In Ward, the North Carolina Supreme Court
held that the visual inspection methodology proffered by the
State’s expert was not sufficiently reliable to identify the pills at
issue as containing a controlled substance. Ward, 364 N.C. at
142-48 (method of proof was not sufficiently reliable); see also
State v. Brunson, 204 N.C. App. 357, 359-61 (2010) (holding, in a
pre-Ward case, that it was plain error to allow an expert to opine
that the substance at issue was hydrocodone, an opium
derivative, based on visual identification and Micromedex
Literature). It is unlikely that the court’s reasoning would lead it to
a different result under the more stringent Daubert standard. And
in fact, one court of appeals case has applied that rule to a case in
which the amended rule applied. State v. Alston, __ N.C. App.
___, ___ S.E.2d ___ (June 20, 2017) (even if officer had been an
expert it would have been error to allow him to testify that pills
found at the defendant's home were Oxycodone and Alprazolam,
where the basis of his identification was a visual inspection and
comparison of the pills with a website).
In cases decided after Ward, the Court of Appeals has held
that visual identification cannot be used to identify a substance as
cocaine, State v. Jones, 216 N.C. App. 519, 526 (2011), or pills as
a controlled substance. State v. Alston, __ N.C. App. ___, ___
S.E.2d ___ (June 20, 2017). However, it has allowed visual
identification to identify a substance as marijuana. State v.
Johnson, 225 N.C. App. 440, 455 (2013) (holding that the State
was not required to test the substance alleged to be marijuana
where the arresting officer testified without objection that based on
his training the substance was marijuana); State v. Mitchell, 224
N.C. App. 171, 178-79 (2012) (an officer properly was allowed to
identify the substance at issue as marijuana based on his “visual
and olfactory assessment”; a chemical analysis of the marijuana
was not required); Jones, 216 N.C. App. at 526 (visual
identification of marijuana was permissible); State v. Garnett, 209
N.C. App. 537, 546 (2011) (Special Agent, who was an expert in
forensic chemistry, properly made an in-court visual identification
of marijuana).
It is difficult to reconcile the Court of Appeals’ post-Ward
decisions on visual identification with respect to substances that
are not controlled substances. Compare State v. Hanif, 228 N.C.
App. 207, 209-13 (2013) (applying Ward in a counterfeit controlled
substance case where the defendant was charged with
representing tramadol hydrochloride, a substance that is not a
controlled substance, as Vicodin, a Schedule III controlled
substance; holding that the trial court committed plain error by
admitting evidence identifying the substance as tramadol
hydrochloride based solely upon an expert’s visual inspection (a
comparison of the tablets’ markings to a Micromedex online
database)), with State v. Hooks, ___ N.C. App. ___, 777 S.E.2d
133, 140-41 (2015) (in a case involving charges of possession of
Criminal Evidence: Expert Testimony − 36
the precursor chemical pseudoephedrine with intent to
manufacture methamphetamine, the court rejected the
defendant’s argument that the evidence was insufficient because
the substance was not chemically identified as pseudoephedrine;
holding that Ward was limited to identifying controlled substances,
and pseudoephedrine is not listed as such a substance).
c. Narcotics indicator field test kits (NIKs) & “NarTest”
Machines. In several cases decided under the more lenient
Howerton standard, the North Carolina Court of Appeals held that
the State failed to establish the reliability of certain narcotics
indicator field tests. State v. Meadows, 201 N.C. App. 707, 708-12
(2010) (the trial court committed prejudicial error by admitting
expert testimony on the identity of a controlled substance based
on the results of a NarTest machine where the State failed to
demonstrate the machine’s reliability); State v. Jones, 216 N.C.
App. 519, 523-25 (2011) (following Meadows and holding that the
trial court erred by allowing a police captain to testify that the
results from a NarTest machine analysis showed that the
substance at issue was a controlled substance; also holding that
the trial court erred by admitting testimony by the State’s expert in
forensic chemistry, a NarTest employee, regarding the reliability of
the NarTest machine where the machine had not been licensed or
certified by any state agency or department, the expert had not
done any independent research on the machine outside of his
duties as a company employee, the State presented no evidence
that the machine had been recognized as a reliable method of
testing by other experts in the field, the State presented no
publications or research performed by anyone unassociated with
NarTest, and although the State offered a visual aid to support the
expert’s testimony, that aid was a NarTest promotional video);
State v. Carter, 237 N.C. App. 274, 281-84 (2014) (following
Meadows and holding that the State failed to demonstrate the
reliability of a NIK—apparently a wipe that turns blue when it
comes into contact with cocaine—and that therefore the trial court
abused its discretion by admitting an investigator’s testimony that
the NIK indicated the presence of cocaine). Absent different
evidence, it is unlikely that the court’s reasoning would lead it to a
different result under the stricter Daubert standard.
d. Other Methods of Drug Identification. In Ward, the Supreme
Court held that “[u]nless the State establishes . . . that another
method of identification is sufficient to establish the identity of the
controlled substance beyond a reasonable doubt, some form of
scientifically valid chemical analysis is required” to identify a
substance as a controlled substance. Ward, 364 N.C. at 147
(emphasis added). This language opens the door, in certain
circumstances, to the use of methods of drug identification other
than chemical testing.
In State v. Woodard, 210 N.C. App. 725 (2011), an opium
trafficking case arising from a pharmacy break-in, the court
rejected the defendant’s argument that the evidence was
Criminal Evidence: Expert Testimony − 37
insufficient to support the conviction because no chemical analysis
was done on the pills at issue. Id. at 730-31. In so holding the
court approved a method of drug identification other than chemical
analysis. Citing Ward, the court determined that the State is not
required to conduct a chemical analysis on a controlled
substance, provided it establishes the identity of the controlled
substance beyond a reasonable doubt by another method of
identification. Here, the State did that through the drug store’s
pharmacist manager, Mr. Martin, who testified that 2,691 tablets of
hydrocodone acetaminophen, an opium derivative, were stolen
from the pharmacy. He testified that he kept “a perpetual
inventory” of all drug items. Using that inventory, he could account
for the type and quantity of every inventory item throughout the
day, every day. Accordingly, he was able to identify which pill
bottles were stolen from the pharmacy by examining his inventory
against the remaining bottles, because each bottle was labeled
with an identifying sticker, date of purchase and a partial
pharmacy account number. These stickers helped the pharmacist
to determine that 2,691 tablets of hydrocodone acetaminophen
were stolen. He further testified, based on his experience and
knowledge as a pharmacist, that the weight of the stolen pills was
approximately 1,472 grams. The court concluded:
Based on Mr. Martin's thirty-five years of
experience dispensing the same drugs that were
stolen from the . . . Drugstore, and based on Mr.
Martin's unchallenged and uncontroverted
testimony regarding his detailed pharmacy
inventory tracking process, we are persuaded that
Mr. Martin's identification of the stolen drugs as
more than 28 grams of opium derivative
hydrocodone acetaminophen was sufficient
evidence to establish the identity and weight of the
stolen drugs and was not analogous to the visual
identifications found to be insufficient in Ward . . . .
Id. at 732.
e. Sampling. The Ward court stated that its ruling regarding visual
identification did not mean that every single item at issue must be
chemically tested. In that case, the State submitted sixteen
batches of items consisting of over four hundred tablets to the SBI
laboratory for testing. Ward, 364 N.C. at 148. The court held:
A chemical analysis of each individual tablet is not
necessary. The SBI maintains standard operating
procedures for chemically analyzing batches of
evidence, and the propriety of those procedures is
not at issue here. A chemical analysis is required in
this context, but its scope may be dictated by
whatever sample is sufficient to make a reliable
Criminal Evidence: Expert Testimony − 38
determination of the chemical composition of the
batch of evidence under consideration.
Id. Cases decided since Ward finding sampling analysis sufficient
include:
State v. Hunt, ___ N.C. App. ___, 790 S.E.2d 874, 881-83
(2016). Testimony from the State’s expert sufficiently
established a trafficking amount of opium; following lab
protocol, the forensic analyst grouped the pharmaceutically
manufactured pills into four categories based on their
physical characteristics and then chemically analyzed one
pill from three categories and determined that they tested
positive for oxycodone; he did not test the pill in the final
category because the quantity was already over the
trafficking amount; the pills that were not chemically
analyzed were visually inspected; the analyst was not
required to chemically analyze each tablet and his
testimony provided sufficient evidence to establish a
trafficking amount.
State v. Lewis, ___ N.C. App. ___, 779 S.E.2d 147, 148-49
(2015). In this conspiracy to traffic in opiates case, the
evidence was sufficient where the State’s expert analyzed
only one of 20 pills, determined its weight and that it
contained oxycodone, an opium derivative, and confirmed
that the remaining pills were visually consistent with the
one that was tested, in terms of size, shape, form and
imprints; a chemical analysis of each individual pill was not
necessary.
State v. James, 240 N.C. App. 456, 459 (2015). In this
opium trafficking case, the evidence was sufficient to
establish a trafficking amount where the expert chose at
random certain pills for chemical testing and each tested
positive for oxycodone; the expert visually inspected the
remaining, untested pills and concluded that with regard to
color, shape, and imprint, they were “consistent with” the
pills that tested positive for oxycodone.
State v. Dobbs, 208 N.C. App. 272, 275-76 (2010). The
trial court did not err by denying the defendant’s motion to
dismiss a trafficking charge where the State’s expert
testified that all eight tablets were similar with respect to
color and imprint and that a test on one tablet revealed it to
be an opiate derivative.
f. Unlicensed & Unaccredited Labs. In a case decided under the
more lenient Howerton standard, the North Carolina Court of
Appeals held to be inadmissible results from a lab that was neither
licensed nor accredited by any agency. State v. Jones, 216 N.C.
Criminal Evidence: Expert Testimony − 39
App. 519, 525-26 (2011) (the trial court improperly admitted
evidence that an individual tested the substances at issue at a
NarTest company laboratory using SBI protocol and determined
that the substances were cocaine and marijuana). By comparison,
test results from a NarTest lab showing that a substance was
cocaine have been found to be admissible where the lab was not
accredited but was licensed by the State of North Carolina and the
Drug Enforcement Agency to perform analytical testing of
controlled substances. State v. McDonald, 216 N.C. App. 161,
163-67 (2011) (note that a NarTest machine was not used in the
testing of the substances at issue).
15. Fire Investigation Experts. In arson cases, an expert may be offered to
opine on, for example, where or how the fire started and whether the fire
was intentionally set. W
HARTON'S CRIMINAL EVIDENCE § 13:55. At the
outset, it should be noted that “fire and explosion investigation consists of
a wide array of distinctive methods, techniques, and principles,” 5
M
ODERN SCIENTIFIC EVIDENCE at 74, which must be assessed separately.
There do not appear to be any published North Carolina cases
applying the Daubert standard to this type of expert testimony. Although
one recent Court of Appeals case held that if a proper foundation is laid
as to expertise, a fire marshal may offer his expert opinion that a fire was
intentionally set, State v. Jefferies, ___ N.C. App. ___, 776 S.E.2d 872,
875 (2015), that case did not mention Daubert and it is not clear that
amended Rule 702 applied to that case. Citing case law decided prior to
the 2011 amendments to Rule 702, that court reasoned:
Generally, the admission of expert opinion testimony is
only allowed where “the opinion expressed is ... based on
the special expertise of the expert[.]’ State v. Wilkerson,
295 N.C. 559, 569, 247 S.E.2d 905, 911 (1978). However,
our Supreme Court has held that, with a proper foundation
laid as to his expertise, a fire marshal may offer his expert
opinion as to whether a fire was intentionally set. State v.
Hales, 344 N.C. 419, 424–25, 474 S.E.2d 328, 330–31
(1996).
Id. The only other published criminal case decided after Daubert became
the law in North Carolina declined to address the defendant’s argument
that the trial court erred by failing to evaluate, under Daubert, testimony
by an investigator with the Fire Prevention Bureau of a city fire
department that the fire in question was intentionally set. State v. Hunt,
___ N.C. App. ___, 792 S.E.2d 552, 560-61 (2016). Instead, that court
concluded that even if error occurred, it did not rise to the level of plain
error. Id.
It has been noted that after Daubert and Kumho Tire, some courts
have examined this type of expert testimony more critically. 5 M
ODERN
SCIENTIFIC EVIDENCE at 75, 78; see also WHARTON'S CRIMINAL EVIDENCE §
13:55 (noting that “[s]ince Daubert the qualifications and conclusions of
arson investigators have been questioned with increasing frequency” and
stating that scholarship has revealed that some investigators fail to base
their conclusions adequately upon the scientific method or scientific tests
Criminal Evidence: Expert Testimony − 40
and has debunked several theories upon which investigators have
historically relied; further indicating that inherent problems in the
investigatory process have surfaced, and it has become apparent that
some fire investigators over-exaggerate arson occurrence as well as the
incidence of fire-related injury and death). For a survey of cases dealing
with expert opinions in arson cases, see Jay M. Zitter, Admissibility of
Expert and Opinion Evidence as to Cause or Origin of Fire in Criminal
Prosecution for Arson or Related Offense—Modern Cases, 85 A.L.R.5th
187 (originally published 2001).
16. Accident Reconstruction. In North Carolina, “[a]ccident reconstruction
opinion testimony may only be admitted by experts.” State v. Maready,
205 N.C. App. 1, 17 (2010) (error to allow officers’ opinion testimony
concerning their purported accident reconstruction conclusions where the
officers were not qualified as experts).
Subsection (i) of Rule 702 provides that “[a] witness qualified as
an expert in accident reconstruction who has performed a reconstruction
of a crash, or has reviewed the report of investigation, with proper
foundation may give an opinion as to the speed of a vehicle even if the
witness did not observe the vehicle moving.”
There do not appear to be any North Carolina criminal cases
evaluating accident reconstruction experts under the Daubert standard.
However, a number of criminal cases decided prior to the 2011
amendments to Rule 702(a) have admitted such evidence. See, e.g.,
State v. Brown, 182 N.C. App. 115, 120 (2007); State v. Speight, 166
N.C. App. 106, 116-17 (2005), vacated on other grounds, 548 U.S. 923
(2006); State v. Holland, 150 N.C. App. 457, 461-464 (2002); State v.
Purdie, 93 N.C. App. 269, 274-76 (1989). Additionally, at least one North
Carolina civil case has allowed accident reconstruction testimony under
the new Daubert standard. Pope v. Bridge Broom, Inc., 240 N.C. App.
365, 369-78 (trial court did not abuse its discretion by admitting expert
accident reconstruction testimony), review denied, ___ N.C. ___, 775
S.E.2d 861 (2015). For a general discussion of courts’ treatment of expert
accident reconstruction testimony, see 5 M
ODERN SCIENTIFIC EVIDENCE at
829-59.
17. Pathologists & Cause of Death. In cases decided both before and after
the amendments to Rule 702(a), North Carolina courts have admitted
expert pathologist testimony regarding cause of death. Cases decided
under the earlier version of Rule 702(a) include, for example: State v.
Johnson, 343 N.C. 489, 492 (1996) (the trial court did not err in this
murder case by allowing a fellow in the Chief Medical Examiner’s office to
testify as an expert in pathology as to cause of death and the possible
range from which the shots were fired where the witness was not yet
certified and had not completed formal training as a forensic pathologist
but had performed a number of autopsies prior to performing the one in
question); State v. Miller, 302 N.C. 572, 580 (1981) (the trial court did not
err by allowing an expert forensic pathologist to testify regarding the size
or gauge of the gun used as the murder weapon); State v. Morgan, 299
N.C. 191, 206-07 (1980) (rejecting the defendant’s challenge to expert
testimony offered by the N.C. Chief Medical Examiner that the cause of
death was “a shotgun wound, shotgun blast” and noting: “It has long been
the rule in North Carolina that the cause of an individual's death is the
Criminal Evidence: Expert Testimony − 41
proper subject of expert testimony.”); State v. Borders, 236 N.C. App.
149, 175-76 (2014) (the trial court did not err by allowing the State’s
forensic pathologists to testify that the cause of death was asphyxiation,
even where no physical evidence supported that conclusion; the experts
knew that the victim’s home was broken into, that she had been badly
bruised, that she had abrasions on her arm and vagina, that her
underwear was torn, and that DNA obtained from a vaginal swab
containing sperm matched the defendant's DNA samples; the experts’
physical examination did not show a cause of death, but both doctors
drew upon their experience performing autopsies in stating that
suffocation victims often do not show physical signs of asphyxiation and
they eliminated all other causes of death before arriving at asphyxiation);
State v. Smith, 157 N.C. App. 493, 498 (2003) (the trial court did not err
by allowing the medical examiner to offer an opinion that the victim was
killed when struck by the passenger side of the truck's door frame); State
v. Evans, 74 N.C. App. 31, 35 (1985) (in this involuntary manslaughter
case, the trial properly allowed a pathologist to testify that the child
victim’s injuries were not self-inflicted, that the child would not have died
but for them, and that a subdural hematoma was a significant cause of
death; he further testified that the hematoma could have been caused by
violent shaking, causing tearing of the blood vessels between the dura
and the brain, adding that death could result either from swelling of the
brain or from rapid trauma to the brain from alteration of the blood
supply), aff'd, 317 N.C. 326 (1986).
For a case decided under the amended version of Rule 702(a),
see State v. Ford, ___ N.C. App. ___, 782 S.E.2d 98, 107-08 (2016) (in
this involuntary manslaughter case, where the defendant’s pit bull
attacked and killed the victim, the trial court did not commit plain error by
allowing a forensic pathologist to opine that the victim’s cause of death
was exsanguination due to dog bites).
For a discussion of expert testimony using the words “homicide” or
“homicidal,” see Section III.B. below.
18. Polygraphs. In a case decided prior to the amendment to Rule 702(a),
the North Carolina Supreme Court held that polygraph evidence is
inadmissible at trial because of the inherent unreliability of polygraph
tests. State v. Grier, 307 N.C. 628, 642–45 (1983) (polygraph evidence is
inadmissible, even if the parties stipulate to its admissibility); see also
State v. Ward, 364 N.C. 133, 146 (2010) (noting this holding). Absent
some change in the relevant technology, there is little reason to think that
the court would rule otherwise under the stricter Daubert standard.
19. Penile Plethysmography. Penile plethysmography tests a man’s level of
sexual arousal. Michael C. Harlow & Charles L. Scott, Penile
Plethysmography Testing for Convicted Sex Offenders, 35 J.
OF AM.
ACADEMY OF PSYCHIATRY & LAW 536 (2007),
http://jaapl.org/content/35/4/536. It “involves placing a pressure-sensitive
device around a man’s penis, presenting him with an array of sexually
stimulating images, in determining his level of sexual attraction by
measuring minute changes in his erectile responses.” Id. at 536
(quotation omitted).
Criminal Evidence: Expert Testimony − 42
Deciding an issue of first impression in a child sex case decided
before the 2011 amendments to Rule 702(a), the North Carolina Court of
Appeals held that the trial court did not abuse its discretion by excluding
opinion testimony by a defense expert in clinical psychology based on
penile plethysmograph testing administered to the defendant. State v.
Spencer, 119 N.C. App. 662, 664-68 (1995) (the expert would have
testified that the defendant had a normal arousal pattern and that there
was no evidence of his being sexually aroused by children; the trial court
did not abuse its discretion in finding the defendant’s plethysmograph
testing data insufficiently reliable to provide a basis for the opinion
testimony).
Although there do not appear to be any North Carolina cases
deciding this issue under the new, stricter Daubert test, the Fourth Circuit
has held that a trial court did not abuse its discretion by ruling that a
penile plethysmograph test did not meet Daubert’s scientific validity
prong. United States v. Powers, 59 F.3d 1460, 1471 (4th Cir. 1995)
(holding, in a child sex case, that the district court did not err by excluding
the testimony of a clinical psychologist who would have testified that the
results of a penile plethysmograph test did not indicate that the defendant
exhibited pedophilic characteristics).
20. Experts in Crime & Criminal Practices. A number of North Carolina
appellate cases decided under the pre-amendment version of Rule 702(a)
found no error where the trial court allowed a law enforcement officer to
testify as an expert regarding criminal practices and activity. For example,
in State v. Jennings, 209 N.C. App. 329 (2011), a child sexual assault
case, the court noted:
[T]his Court has held that law enforcement officers may
properly testify as experts about the practices criminals
use in concealing their identity or criminal activity. See
State v. Alderson, 173 N.C. App. 344, 350–51, 618 S.E.2d
844, 848–49 (2005) (holding trial court properly permitted
SBI agent to “give her opinion as to why the seizure of
defendant's police frequency book was important, testifying
that finding a police frequency book and a radio scanner
can indicate those acting illegally may have a ‘jumpstart’ if
they know which police frequencies to monitor.”); State v.
White, 154 N.C. App. 598, 604, 572 S.E.2d 825, 830–31
(2002) (“Lieutenant Wood had ‘training, and various
courses and experience in working certain cases' which
led him to conclude that ‘there are times that the
significance of an object such as a pillow or a cloth being
placed over somebody's face can mean in a case that the
perpetrator knew the victim and did not want to see their
face or have their face appear either before, during, or
after the crime.’ Since Lieutenant Wood testified in the
form of an opinion based on his expertise, and the
testimony was likely to assist the jury making an inference
from the circumstances of the crime, the trial court properly
admitted the testimony.”).
Criminal Evidence: Expert Testimony − 43
Id. at 337–38. Jennings went on to hold that a law enforcement officer
qualified as an expert in forensic computer examination properly was
allowed to testify that those who have proof of criminal activity on a
computer will attempt to hide that evidence and that the defendant would
have been unlikely to save an electronic conversation that would have
implicated him. That testimony was elicited by the State to explain why,
despite the victim’s testimony that she and the defendant routinely
communicated through instant messaging and their MySpace web page
and that the defendant took digital photographs of her vaginal area during
sex, no evidence of these communications or photographs were
recovered from the defendant's electronic devices.
There do not appear to be any published North Carolina criminal
cases analyzing this type of expert testimony under the new Daubert
standard. A number of federal circuit courts have allowed such testimony
under that standard. For example, law enforcement officers have been
allowed to testify as experts regarding:
• Drug code words. See, e.g., United State v. York, 572 F.3d
415, 422 (7th Cir. 2009) (“[W]e allow officers whose testimony
is based on some aspect of that understanding (such as the
meaning of drug code words), rather than on first-hand
knowledge of the particular investigation in the case, to testify
as experts.”); United States v. Dukagjini, 326 F.3d 45, 52 (2d
Cir. 2003) (“[W]e have consistently upheld the use of expert
testimony to explain both the operations of drug dealers and
the meaning of coded conversations about drugs. In particular,
we have recognized that drug dealers often camouflage their
discussions and that expert testimony explaining the meanings
of code words may ‘assist the trier of fact to understand the
evidence or to determine a fact in issue.’” (citation omitted)).
• The use of firearms in the drug trade and common practices of
drug dealers. See, e.g., United States v. Garza, 566 F.3d
1194, 1199 (10th Cir. 2009) (“[W]e do not believe that Daubert
and its progeny . . . provide any ground for us to depart from
our pre-Daubert precedents recognizing that police officers
can acquire specialized knowledge of criminal practices and
thus the expertise to opine on such matters as the use of
firearms in the drug trade.”); United States v. Norwood, 16 F.
Supp. 3d 848, 852-54 (E.D. Mich. 2014) (citing cases and
holding to be admissible testimony by a DEA agent with fifteen
years’ experience regarding drug trafficking and use of
firearms in drug trafficking).
• Gang practices. See, e.g., United States v. Hankey, 203 F.3d
1160, 1167-70 (9th Cir. 2000) (the trial court did not abuse its
discretion in admitting an officer’s expert opinion testimony
regarding the co-defendants’ gang affiliations and the
consequences an individual would suffer if he were to testify
against the defendant; among other things, the expert had
been with the police department for twenty-one years, worked
undercover “with gang members in the thousands,” received
formal training in gang structure and organization, and he
Criminal Evidence: Expert Testimony − 44
taught classes about gangs; stating: “The Daubert factors
(peer review, publication, potential error rate, etc.) simply are
not applicable to this kind of testimony, whose reliability
depends heavily on the knowledge and experience of the
expert, rather than the methodology or theory behind it.”).
However, some federal court Daubert decisions have excluded such
testimony as unreliable, at least in certain circumstances. See, e.g.,
Norwood, 16 F. Supp. 3d at 854-64 (excluding proffered expert testimony
concerning gangs where the witness formed his opinions based on his
experience in Oklahoma, California, and Connecticut and from a national
perspective while in Washington, D.C. but the case in question concerned
a gang that operated in Flint, Michigan; the witness never investigated the
gang in question or other Michigan gangs; “Simply put, [the witness’s]
lack of familiarity with the particular gang or locale at issue in this case
makes his opinions unreliable to be placed before the jury.”).
Other courts, while noting that an officer involved in an
investigation may testify as both a fact and expert witness, also have
noted the “inherent dangers” associated with this type of “dual testimony.”
See, e.g., York, 572 F.3d at 425; Dukagjini, 326 F.3d at 53 (“While expert
testimony aimed at revealing the significance of coded communications
can aid a jury in evaluating the evidence, particular difficulties, warranting
vigilance by the trial court, arise when an expert, who is also the case
agent, goes beyond interpreting code words and summarizes his beliefs
about the defendant's conduct based upon his knowledge of the case.”).
Those dangers include that the witness’s dual role might confuse the jury,
that the jury might be impressed by an expert’s “aura of special reliability”
and thus give his or her factual testimony undue weight, or that “the jury
may unduly credit the opinion testimony of an investigating officer based
on a perception that the expert was privy to facts about the defendant not
presented at trial.” York, 572 F.3d at 425 (citing cases); see also
Dukagjini, 326 F.3d at 53 (noting other dangers as well). Precautions that
can mitigate these dangers include ensuring that the jury knows when an
officer is testifying as an expert versus as a fact witness, through the use
of cautionary instructions or witness examination that is structured to
make clear when the witness is testifying to facts and when he or she is
offering an expert opinion. York, 572 F.3d at 425-26 (discussing other
precautions and going on to hold that admission of certain “dual
testimony” by the officer in question was improper). And courts have
noted that the trial court should be careful to ensure that the law
enforcement officer expert does not “stray from his proper expert function”
of offering opinions based on expertise and opine about matters based on
his or her investigation in the case. Dukagjini, 326 F.3d at 54-55 (witness
improperly acted “as a summary prosecution witness” when, for example,
he testified about the meaning of conversations in general, as opposed to
interpretation of drug code words).
Some commentators have been critical of decisions that
reflexively allow police officers to testify as expert on criminal practices.
See 1 M
ODERN SCIENTIFIC EVIDENCE at 101, 104 (although not advocating
for a wholesale exclusion of such testimony, stating: “Somewhat
disappointing has been the courts’ willingness to admit prosecution
Criminal Evidence: Expert Testimony − 45
experts who have little research or data to support their opinions. While
there is some evidence that this is changing in some areas, such as the
forensic sciences, courts continue to permit many prosecution experts
with hardly a glance at the methods underlying their testimony. Perhaps
the best example is the testimony of police officers testifying as expert
witnesses.”).
III. Form & Scope of Expert’s Opinion. For a discussion of the proper scope of an
expert’s opinion in sexual assault cases, see
Evidence Issues in Criminal Cases
Involving Child Victims and Child Witnesses, in this Benchbook, and more current cases
annotated in
Smith’s Criminal Case Compendium (under Evidence; Opinions; Experts;
Sexual Assault Cases).
A. Form of Testimony. Rule 702(a) allows for flexibility as to the form of the
expert’s testimony, providing that the expert may testify to “an opinion, or
otherwise.” Rule 705 provides that “[t]here shall be no requirement that expert
testimony be in response to a hypothetical question.” See, e.g., State v. Fearing,
304 N.C. 499, 503-04 (1981) (no requirement that testimony of a forensic
pathologist be given only in response to a hypothetical question); State v.
Morgan, 299 N.C. 191, 205 (1980) (“It is settled law in North Carolina that an
expert witness need not be interrogated by means of a hypothetical question . . .
.”).
B. Opinion on Ultimate Issue & Legal Standards. Although an expert may not
testify to an opinion as to the defendant’s guilt or innocence, see, e.g., State v.
Heath, 316 N.C. 337, 341-42 (1986), Evidence Rule 704 provides that
“[t]estimony in the form of an opinion or inference is not objectionable because it
embraces an ultimate issue to be decided by the trier of fact.” See also State v.
Hill, 116 N.C. App. 573, 581 (1994) (noting this rule and rejecting the defendant’s
argument that testimony by the State’s DNA expert regarding a DNA match
improperly stated an opinion that the defendant had committed the rape in
question).
The North Carolina Supreme Court has explained, however:
In interpreting Rule 704, this Court draws a distinction
between testimony about legal standards or conclusions
and factual premises. An expert may not testify regarding
whether a legal standard or conclusion has been met at
least where the standard is a legal term of art which carries
a specific legal meaning not readily apparent to the
witness. Testimony about a legal conclusion based on
certain facts is improper, while opinion testimony regarding
underlying factual premises is allowable.
State v. Parker, 354 N.C. 268, 289-90 (2001) (internal citations and quotation
marks omitted). Applying this rule, cases have held that it is not error to allow:
• a pathologist to testify that a killing was a “homicide” or “homicidal,”
see, e.g., State v. Flippen, 344 N.C. 689, 699 (1996) (no error to allow
the State’s forensic pathologist expert to testify that the victim died as
Criminal Evidence: Expert Testimony − 46
a result of a “homicidal assault”); State v. Parker, 354 N.C. 268, 290
(2001) (citing Flippen and holding that it was not error to allow the
State’s forensic pathologist expert to testify that the victim’s death was
a homicide); State v. Hayes, 239 N.C. App. 539, 549-50 (2015) (no
error to allow forensic pathology experts to testify that the cause of
death was “homicide by unde[te]rmined means” and “homicidal
violence”);
• an expert in psychiatry and addiction medicine to testify that the
defendant lacked the capacity to form the specific intent to kill, see,
e.g., State v. Daniel, 333 N.C. 756, 760-64 (1993) (trial court erred by
excluding testimony from a defense expert to this effect; noting that
although it has held that expert testimony regarding precise legal
terms should be excluded, “specific intent to kill” is not one of those
precise legal terms that is off limits);
• a mental health expert to testify that the defendant lacked the capacity
to plan, think, or reflect, Daniel, 333 N.C. at 760-64 (first-degree
murder case), that the defendant’s capacity to make and carry out
plans was impaired, State v. Shank, 322 N.C. 243, 246-251 (1988)
(new trial required in first-degree murder case where the trial court
excluded this evidence); see also State v. Fisher, 336 N.C. 684, 704
(1994) (noting that a defense expert properly was allowed to opine
regarding the defendant’s ability to formulate and carry out a plan), or
that the defendant acted while under the influence of a mental or
emotional disturbance, Shank, 322 N.C. at 246-51 (new trial required
in a first-degree murder case where the trial court excluded this
evidence);
• an expert to testify that the defendant acted with an intent to cause
death, State v. Teague, 134 N.C. App. 702, 708–09 (1999) (proper to
allow expert to opine that one of the victim's “gunshot wounds to the
head was consistent with an intent to cause death”);
• an endocrinologist, in a case involving a defense of automatism, to
testify that the defendant’s actions were “not caused by automatism
due to hypoglycemia” and that he reached this conclusion because
the defendant did not experience amnesia, a characteristic feature of
automatism caused by hypoglycemia, State v. Coleman, ___ N.C.
App. ___, ___ S.E.2d ___ (July 18, 2017);
• a forensic pathologist who performed the autopsy to testify that the
victim was “tortured,” where the defendant was charged with first-
degree murder on the basis of torture, State v. Jennings, 333 N.C.
579, 597-600 (1993);
• a forensic pathologist who conducted the autopsy to testify that the
victim experienced a “sexual assault,” Jennings, 333 N.C. at 600-601;
see also State v. O'Hanlan, 153 N.C. App. 546, 553-57 (2002) (citing
Jennings and holding that medical doctors who examined the victim
properly testified that she was sexually assaulted);
• a pathologist who did the autopsy to testify that that defendant's
account of the shooting was inconsistent with the type of wound
suffered by victim and that the wound was not a self-defense type
wound, even though self-defense was an ultimate issue in the case,
State v. Saunders, 317 N.C. 308, 314 (1986);
Criminal Evidence: Expert Testimony − 47
• a physician to testify that a sexual assault victim’s injuries were
caused by a male penis, State v. Smith, 315 N.C. 76, 99-100 (1985)
(noting that the witness did not testify that the victim had been raped
or that the defendant had raped her);
• a radiologist to testify, in an assault inflicting serious injury case, that
based on the victim’s CT scan, the “trauma was definitely very serious
intracranial trauma with serious brain injury and serious orbital injury
with all the bone damage that was suffered,” State v. Liggons, 194
N.C. App. 734, 743-44 (2009) (concluding that the expert’s opinion
was not inadmissible on the basis that it embraced an ultimate issue
to be determined by the jury).
However, it is improper to allow:
• an expert in pathology and medicine, in a homicide case, to testify
that injuries suffered by the victim were a “proximate cause of [the
victim’s] death,” State v. Ledford, 315 N.C. 599, 617-19 (1986) (error
to allow the expert to testify that a legal standard—“proximate
cause”—had been met);
• a mental health expert to testify, in a murder case, that a defendant
did or did not premeditate or deliberate, State v. Weeks, 322 N.C.
152, 166–67 (1988) (proper to exclude defense proffered expert
testimony that the defendant did not act with deliberation); State v.
Cabe, 131 N.C. App. 310, 313-14 (improper to allow the State’s
expert to testify that the defendant acted with premeditation and
deliberation, but allowable here where the defendant opened the
door), or that the defendant possessed or lacked the capacity to
premeditate or deliberate, State v. Rose, 323 N.C. 455, 459-60 (1988)
(Rose I) (proper to exclude such testimony); State v. Rose, 327 N.C.
599, 601-05 (1990) (Rose II) (the trial court committed reversible error
by allowing the State’s expert to testify that the defendant was
capable of “premeditating”); State v. Mash, 328 N.C. 61, 65-66 (1991)
(proper to exclude defense proffered expert testimony regarding the
defendant’s ability to premediate and deliberate);
• a mental health expert to testify, in a murder case, that the defendant
did not act in a “cool state of mind,” Weeks, 322 N.C. at 165–67; State
v. Boyd, 343 N.C. 699, 708-10 (1996) (holding that under Weeks and
Rule 403, the trial court did not err by preventing a forensic
psychologist from using the phrase “cool state of mind” to convey his
opinion that the defendant lacked the specific intent necessary to
commit premeditated and deliberate murder at the time of the
shootings), or under a suddenly aroused violent passion, Weeks, 322
N.C. at 165-67.
• a mental health expert to testify that the defendant lacked the capacity
to conspire, State v. Brown, 335 N.C. 477, 489 (1994) (no error to
exclude testimony of defense expert in forensic psychiatry with a
specialty in addictive medicine where the term “conspiracy” had a
specific legal definition);
Criminal Evidence: Expert Testimony − 48
• a medical doctor who examined the victim to testify that she had been
“raped” and “kidnapped,” State v. O'Hanlan, 153 N.C. App. 546, 557-
58 (2002);
• a mental health expert to testify about the law of voluntary intoxication
and its effect on the defendant's insanity defense, State v. Silvers,
323 N.C. 646, 655-57 (1989) (agreeing with the defendant’s argument
that a defense expert was erroneously permitted to offer legal
conclusions during cross-examination by the State).
C. Opinion on Credibility of Witness. Expert testimony on the credibility of a
witness is not admissible. State v. Heath, 316 N.C. 337, 340-43 (1986) (holding
that the expert’s testimony was improper for this reason); State v. Aguallo, 318
N.C. 590, 598-99 (1986) (citing Heath and holding that the trial court erred by
allowing a pediatrician to testify that a rape victim was “believable”); State v.
Green, 209 N.C. App. 669, 676-77 (2011) (so stating this rule but holding that in
this case, the expert’s testimony regarding the defendant’s blood alcohol level did
not constitute impermissible opinion testimony). Thus, it is error to allow an
expert to testify that she believed the victim and to the reason for this belief.
State v. Teeter, 85 N.C. App. 624, 631-32 (1987) (testimony by a nurse tendered
as an expert for the State with respect to sexually abused mentally retarded
adults). However, drawing the line between permissible and impermissible expert
testimony in this area can be difficult. In Teeter, for example, it was not error for a
mental health expert to testify that an adult sexual assault victim who suffered
certain mental impairments showed no evidence of a disorder that would impair
her ability to distinguish reality from fantasy. Id. at 628-29. The court rejected the
defendant’s argument that this testimony amounted to an impermissible expert
opinion concerning the victim’s credibility. Id. Consider by contrast, Heath, in
which clinical psychologist Deborah Broadwell testified as an expert for the State
in a child sexual assault case involving victim Vickie. At trial, defense counsel
asked Vickie if her sister thought she was lying about the attack because Vickie
“had lied about so many other things,” asked Vickie's mother if she had
experienced difficulties with Vickie “making up stories,” and cross-examined
Broadwell about alleged discrepancies in Vickie’s statements to hospital
emergency room and mental health clinic personnel. Heath, 316 N.C. at 339-40.
On redirect, the prosecutor asked Broadwell: “do you have an opinion . . . as to
whether or not Vickie was suffering from any type of mental condition . . . which
could or might have caused her to make up a story about the sexual assault?” Id.
at 340 (emphasis added). Broadwell responded: “There is nothing in the record
or current behavior that indicates that she has a record of lying.” Id. The court
held, in part that the question, focusing as it did on “the sexual assault,” was
improper. It explained:
We would be confronted with an entirely different situation had the
assistant district attorney . . . asked the psychologist if she had an
opinion as to whether Vickie was afflicted with any mental
condition which might cause her to fantasize about sexual
assaults in general or even had the witness confined her response
to the subject of a “mental condition.”
Id. at 341. But because the question focused on the specific incident in question,
it was improper under Evidence Rules 608 and 405(a), which “together, forbid an
Criminal Evidence: Expert Testimony − 49
expert's opinion as to the credibility of a witness.” Id. at 342. Heath thus
emphasizes how fine the line can be between permissible and impermissible
testimony. See also State v. O'Hanlan, 153 N.C. App. 546, 555 (2002) (“[T]he
cases dealing with the line between discussing one's expert opinion and
improperly commenting on a witness' credibility have made it a thin one.”).
Issues regarding impermissible expert opinion testimony on the credibility
of a witness arise most frequently in child sexual assault cases. For a more
detailed discussion of this issue in that context see
Evidence Issues in Criminal
Cases Involving Child Victims and Child Witnesses, in this Benchbook. For more
decisions decided after publication of that Benchbook Chapter, see
Smith’s
Criminal Case Compendium (under Evidence; Opinions; Experts; Sexual Assault
Cases).
D. Basis for Expert’s Opinion.
1. Scope & Adequacy. Evidence Rule 703 provides that “[t]he facts or data
. . . upon which an expert bases an opinion or inference may be those
perceived by or made known to him at or before the hearing.” N.C.
R.
EVID. 703. See generally State v. Morgan, 299 N.C. 191, 206 (1980)
(testimony of Chief Medical Examiner regarding identification of human
remains and cause of death was based on adequate data where the
witness examined the remains, measuring, sorting and photographing
them); State v. McClary, 157 N.C. App. 70, 79 (2003) (a forensic
psychiatrist properly testified as an expert based on his own meetings
with the defendant and his review of psychiatric evaluations done by other
psychiatrists); State v. McCall, 162 N.C. App. 64, 71-73 (2004) (it was not
error for an expert witness to testify that a child victim’s behaviors
suggested exposure to trauma, probably sexual abuse, where the expert
did not personally examine the child; the expert obtained information
about the child from a summary of the child’s testimony, a DSS report,
and the child’s statement to the police; rejecting the defendant’s argument
that the expert’s failure to examine the child rendered her expert opinion
unreliable).
An opinion based on inadequate facts or data should be excluded.
See 2 K
ENNETH S. BROUN, BRANDIS & BROUN ON NORTH CAROLINA
EVIDENCE 742 (2011) [hereinafter BRANDIS & BROUN] (citing cases). As
noted above, when expert testimony is not sufficiently tied to the facts of
the case, it may fail the “fit test” that is part of the relevancy inquiry. See
Section II.B.3. above.
2. Of a Type Reasonably Relied Upon. Rule 703 provides that the facts or
data underlying the expert’s opinion must be “of a type reasonably relied
upon by experts in the particular field in forming opinions or inferences
upon the subject.” N.C.
R. EVID. 703. Compare State v. Demery, 113 N.C.
App. 58, 65-66 (1993) (State’s forensic serologist expert properly relied
on statistical information concerning the frequency of blood group factors
or characteristics in the North Carolina population compiled by the SBI
with blood provided by the Red Cross and blood obtained in criminal
cases; “The statistics on which he relied are commonly used and
accepted in his field in North Carolina, and similar statistics are commonly
used and accepted in forensic serology throughout the country”), State v.
Purdie, 93 N.C. App. 269, 275-76 (1989) (expert in accident
Criminal Evidence: Expert Testimony − 50
reconstruction properly based his opinion on physical evidence), and
State v. Teeter, 85 N.C. App. 624, 628-30 (1987) (clinical psychologist
and expert in adult mental retardation and sexual abuse properly testified
to the opinion that the victim exhibited behavioral characteristics
consistent with sexual abuse; his opinion was based upon his experience
in treating sexually abused mentally retarded persons, his familiarity with
research and literature in that field, and his personal examination of the
victim, all sources reasonably relied upon by experts in the field), with
State v. Galloway, 145 N.C. App. 555, 564-65 (2001) (the trial court
properly excluded statements made by the State’s expert in the victim’s
medical discharge summary referencing the victim’s psychiatric history,
including substance abuse; because the expert was qualified as an expert
in surgery, not psychiatry, the court rejected the defendant’s assertion
that the statements were admissible under Rule 703, finding that they did
not contain facts or data reasonably relied upon by experts in the field of
surgery).
3. Need Not Be Admissible. Rule 703 provides that if of a type reasonably
relied upon by experts in the field, the facts or data forming the basis of
the expert’s opinion “need not be admissible in evidence.” N.C.
R. EVID.
703; see, e.g., State v. Jones, 322 N.C. 406, 410-14 (1988) (trial court did
not err by admitting hearsay evidence as the basis of an expert’s opinion);
State v. Purdie, 93 N.C. App. 269, 277 (1989) (same).
For a discussion of confrontation clause issues related to the
basis of the expert’s opinion, see
Guide to Crawford and the
Confrontation Clause, in this Benchbook.
4. Expert Need Not Interview Victim. Evidence Rule 703 provides that the
facts or data on which an expert bases an opinion “may be those
perceived by or made known to him at or before the hearing.” N.C.
R.
EVID. 703; see Purdie, 93 N.C. App. at 276 (“It is well-settled that an
expert witness need not testify from first-hand personal knowledge . . . .”).
Furthermore, the North Carolina Supreme Court has clarified that an
expert “is not required to examine or interview the prosecuting witness as
a prerequisite to testifying about issues relating to the prosecuting witness
at trial,” noting that “[s]uch a requirement would create a troubling
predicament given that defendants do not have the ability to compel the
State’s witnesses to be evaluated by defense experts.” State v. Walston,
___ N.C. ___, 798 S.E.2d 741, 747 (2017); accord State v. McCall, 162
N.C. App. 64, 71-73 (2004) (it was not error for an expert witness to
testify that a child victim’s behaviors suggested exposure to trauma,
probably sexual abuse, where the expert did not personally examine the
child; the expert obtained information about the child from a summary of
the child’s testimony, a DSS report and the child’s statement to the police;
rejecting the defendant’s argument that the expert’s failure to examine the
child rendered her expert opinion unreliable).
5. Disclosure & Cross-Examination of Basis at Trial.
Although an expert may testify without prior disclosure of the basis for his
or her opinion, disclosure is required when requested by the other side.
Rule 705 provides:
Criminal Evidence: Expert Testimony − 51
The expert may testify in terms of opinion or inference and
give his reasons therefor without prior disclosure of the
underlying facts or data, unless an adverse party requests
otherwise, in which event the expert will be required to
disclose such underlying facts or data on direct
examination or voir dire before stating the opinion. The
expert may in any event be required to disclose the
underlying facts or data on cross-examination.
N.C.
R. EVID. 705; see, e.g., State v. Brown, 101 N.C. App. 71, 76-77
(1990) (noting that under Rule 705 an expert does not have to identify the
basis of his opinion, absent a specific request by opposing counsel;
rejecting the defendant’s argument that the State’s failed to establish a
proper foundation for its expert’s opinion as to the weight of the cocaine
where the expert testified to his opinion but the defendant made no
inquiry as to basis on cross-examination); State v. Fletcher, 92 N.C. App.
50, 57 (1988) (“The basis of an expert's opinion need not be stated unless
requested by an adverse party and here defendant made no such
request.”).
Courts have noted that “[d]isclosure of the basis of the opinion is
essential to the factfinder's assessment of the credibility and weight to be
given to it.” State v. Jones, 322 N.C. 406, 412 (1988). If the party
requesting disclosure does not specify disclosure on voir dire, the trial
court probably can allow for disclosure on voir dire or direct examination
without committing error. 2 B
RANDIS & BROUN at 738 (so noting); see
State v. Pretty, 134 N.C. App. 379, 382-83 (1999) (no error where
disclosure occurred during direct and cross-examination rather than on
voir dire and no prejudice was shown from the delay in obtaining the
evidence). But, if the party seeking disclosure specifically asks for
disclosure on voir dire and the trial court allows disclosure only on direct
examination, prejudicial error may occur if improper evidence is
presented to the jury. 2 B
RANDIS & BROUN at 738. When disclosure is
ordered through voir dire and the trial court admits the opinion, it has
been suggested that the trial court has discretion to require the expert to
state the facts or data before giving the opinion or leave them to be
brought out on cross-examination. Id.
“Wide latitude is generally given to a cross-examiner in his
attempts to discredit the expert witness, including questioning the expert
in order to show that the facts or data forming the basis of the expert's
opinion were incomplete.” State v. Black, 111 N.C. App. 284, 293–94
(1993). As has been explained:
On cross-examination ... opposing counsel may require the
expert to disclose the facts, data, and opinions underlying
the expert's opinion not previously disclosed. With respect
to facts, data, or opinions forming the basis of the expert's
opinion, disclosed on direct examination or during cross-
examination, the cross-examiner may explore whether,
and if so how, the non-existence of any fact, data, or
opinion or the existence of a contrary version of the fact,
data, or opinion supported by the evidence, would affect
Criminal Evidence: Expert Testimony − 52
the expert's opinion. Similarly the expert may be cross-
examined with respect to material reviewed by the expert
but upon which the expert does not rely. Counsel is also
permitted to test the knowledge, experience, and fairness
of the expert by inquiring as to what changes of conditions
would affect his opinion, and in conducting such an inquiry
... the cross-examiner is not limited to facts finding support
in the record. It is, however, improper to inquire of the
expert whether his opinion differs from another expert's
opinion, not expressed in a learned treatise, if the other
expert's opinion has not itself been admitted in evidence.
An expert witness may, of course, be impeached with a
learned treatise, admissible as substantive evidence . . . .
Id. at 294 (quoting M
CCORMICK, MCCORMICK ON EVIDENCE § 13 (1992),
and going on to hold that the trial court properly allowed the defendant to
elicit on cross-examination that the expert never examined certain
medical records, that in formulating similar opinions she often relied upon
such records, and that examination of the records would in fact have
assisted the expert in formulating her opinion in this case; however, the
trial could properly limit the defendant’s cross-examination when he
sought to question the expert regarding the contents of data that the
expert had not considered or used in formulating her opinion and which
was not contained in any recognized learned treatise); see also State v.
White, 343 N.C. 378, 393 (1996) (the trial court properly allowed the State
to cross-examine a defense psychiatry expert about the work of a clinical
psychologist upon which the expert had relied where the expert disagreed
with a conclusion drawn by the clinical psychologist).
Cases have held it to be error when the trial court prohibits
defense counsel from asking a defense expert about the basis of his or
her opinion. State v. Davis, 340 N.C. 1, 25-26 (1995) (error to sustain the
State’s objections to questions posed to the defendant’s mental health
expert about the basis of the expert’s opinion); State v. Allison, 307 N.C.
411, 413-17 (1983) (the trial court committed prejudicial error in a case
involving the insanity defense where it prohibited defense mental health
experts from testifying to the basis of their opinions that the defendant
was unable to distinguish between right and wrong with respect to his
behavior at the time of the alleged crimes).
For a discussion of what discovery must be provided in connection
with expert witnesses, see
Discovery in Criminal Cases in this
Benchbook.
6. Status as Substantive Evidence; Limiting Instruction. When evidence
is admissible as the basis of an expert’s opinion, it is not substantive
evidence unless it qualifies for admission under some independently
recognized principle, such as an exception to the hearsay rule. 2 B
RANDIS
& BROUN at 744-45. One exception to the hearsay rule that might apply is
N.C.
R. EVID. 803(18) (hearsay exceptions, availability of declarant
immaterial), which provides an exception to the hearsay rule as follows:
To the extent called to the attention of an expert witness
upon cross-examination or relied upon by him in direct
Criminal Evidence: Expert Testimony − 53
examination, statements contained in published treatises,
periodicals, or pamphlets on a subject of history, medicine,
or other science or art, established as a reliable authority
by the testimony or admission of the witness or by other
expert testimony or by judicial notice. If admitted, the
statements may be read into evidence but may not be
received as exhibits.
If the evidence does not qualify for admission as substantive
evidence, its admission should be accompanied by an appropriate limiting
instruction. See State v. Jones, 322 N.C. 406, 414 (1988) (noting that the
defendant is entitled to a limiting instruction upon request).
E. Testimony Outside of Expert’s Expertise. An expert’s testimony should relate
to the expert’s area of expertise. State v. Ward, 364 N.C. 133, 146 n.5 (2010)
(“[c]aution should be exercised in assuring that the subject matter of the expert
witness's testimony relates to the expertise the witness brings to the courtroom”
(quotation omitted)). For example, in one recent case the North Carolina
Supreme Court noted that while a defense proffered witness who was a former
police officer and trainer in police use of force matters would have been qualified
to testify about standard police practices regarding the use of force, he was not
qualified to testify about the human body’s sympathetic nervous system. State v.
McGrady, 368 N.C. 880, 896 (2016). By contrast, in another case the Court of
Appeals rejected the defendant’s argument that testimony by a forensic
serologist that the defendant's blood profile was the same as .2% of the
population and the victim's blood profile was the same as 8.2% of the population
was beyond the scope of witness’s expertise. State v. Demery, 113 N.C. App. 58,
63-64 (1993).
F. Terminology.
Although not binding authority for a judge, the PCAST
REPORT asserts that
statements by experts suggesting or implying greater certainty than is shown by
the empirical evidence “are not scientifically valid and should not be permitted.”
PCAST
REPORT at 145. It continues:
In particular, courts should never permit scientifically indefensible
claims such as: “zero,” “vanishingly small,” “essentially zero,”
“negligible,” “minimal,” or “microscopic” error rates; “100 percent
certainty” or proof “to a reasonable degree of scientific certainty;”
identification “to the exclusion of all other sources;” or a chance of
error so remote as to be a “practical impossibility.”
Id.; see also Paul C. Giannelli, The NRC Report and Its Implications for Criminal
Litigation, 50 J
URIMETRICS J. 53, 57-60 (2009) (discussing a similar position in the
2009 report by the National Research Council, entitled, S
TRENGTHENING
FORENSIC SCIENCE IN THE UNITED STATES: A PATH FORWARD, and relevant cases).
IV. Interplay Between Rule 403 & the 700 Rules. Evidence that is admissible under Rule
702 still may be inadmissible under Rule 403. See N.C.
R. EVID. 702(g) (“This section
Criminal Evidence: Expert Testimony − 54
does not limit the power of the trial court to disqualify an expert witness on grounds other
than the qualifications set forth in this section.”). Compare, e.g., State v. King, 366 N.C.
68, 75-76 (2012) (holding that the trial court did not abuse its discretion by excluding
under Rule 403 the expert testimony regarding repressed memory that was admissible
under Rule 702), and State v. Walston, ___ N.C. ___, 798S.E.2d. 741, 746 (2017) (citing
King and noting that Rule 403 would allow for the exclusion of expert testimony—in that
case, regarding repressed memory and the suggestibility of memory—even if such
evidence was admissible under Rule 702), with State v. Cooper, 229 N.C. App. 442, 463
(2013) (in this murder case where files recovered from the defendant’s computer linked
the defendant to the crime, the trial court abused its discretion by excluding under Rule
403 a defense expert proffered to testify that the defendant’s computer had been
tampered with).
Likewise, evidence admissible under Rule 705 may be excluded under Rule 403.
State v. Coffey, 336 N.C. 412, 420-22 (1994) (although Rule 705 allows a party cross-
examining an expert to inquire into the facts on which the expert's opinion is based, that
Rule “does not end the inquiry” and the trial court may exclude such evidence under
Rule 403; where the probative value of evidence of the defendant’s convictions was
substantially outweighed by the danger of unfair prejudice, evidence of the convictions
was not admissible on grounds that they constituted a basis of the expert’s opinion).
V. Court Appointed Experts. Evidence Rule 706(a) provides for court appointed experts.
It provides:
The court may on its own motion or on the motion of any party enter an
order to show cause why expert witnesses should not be appointed, and
may request the parties to submit nominations. The court may appoint
any expert witnesses agreed upon by the parties, and may appoint
witnesses of its own selection. An expert witness shall not be appointed
by the court unless he consents to act. A witness so appointed shall be
informed of his duties by the court in writing, a copy of which shall be filed
with the clerk, or at a conference in which the parties shall have
opportunity to participate. A witness so appointed shall advise the parties
of his findings, if any; his deposition may be taken by any party; and he
may be called to testify by the court or any party. He shall be subject to
cross-examination by each party, including a party calling him as a
witness.
N.C.
R. EVID. 706(a); see also State v. Robinson, 368 N.C. 596, 597 (2015)
(instructing that on remand the trial court may, in its discretion appoint an expert
under the rule).
If the court appoints an expert, the witness is “entitled to reasonable
compensation in whatever sum the court may allow.” N.C.
R. EVID. 706(b).
The rule allows the court, in the exercise of its discretion, to “authorize
disclosure to the jury of the fact that the court appointed the expert witness.” N.C.
R. EVID. 706(c). And it specifies that nothing in the rule limits the parties in calling
expert witnesses of their own selection. N.C.
R. EVID. 706(d).
VI. Defendant’s Right to Expert Assistance.
For a discussion of a criminal defendant’s right to expert assistance and the procedure
for obtaining such assistance, see Chapter 5, Experts and Other Assistance, in J
OHN
Criminal Evidence: Expert Testimony − 55
R
UBIN & ALYSON A. GRINE, NORTH CAROLINA DEFENDER MANUAL VOL. 1, PRETRIAL
(2013),
http://defendermanuals.sog.unc.edu/defender-manual/2.
VII. Standard of Review on Appeal.
In reviewing a trial court’s decision regarding the admissibility of expert testimony, the
appellate courts apply the deferential abuse of discretion standard. See, e.g., Walston,
___ N.C. ___, 798 S.E.2d at 745; McGrady, 368 N.C. at 893; State v. Babich, ___ N.C.
App. ___, 797 S.E.2d 359, 361 (2017); State v. Hunt, ___ N.C. App. ___, 790 S.E.2d
874, 881 (2016).
© 2017, School of Government, University of North Carolina at Chapel Hill. This document may not be copied or posted online, nor
transmitted, in printed or electronic form, without the written permission of the School of Government, except as allowed by fair use
under United States copyright law. For questions about use of the document and permission for copying, contact the School of
Government at [email protected].edu or call 919.966.4119.
Criminal Evidence: Expert Testimony − 56
