706.2Expert Testimony [Rule 702]
Key Concepts
- An expert witness is one whose scientific, technical or other specialized knowledge, acquired through education, training, experience, or otherwise, can assist the trier of fact to understand the evidence or determine or determine a fact in issue.
- An expert witness may testify in the form of an opinion if that opinion is based on sufficient facts or data and is the product of reliable principles and methods reliably applied to the facts of the case.
- In addition to the generally applicable rules governing all expert testimony, Rule 702 establishes specific rules regarding the admissibility of testimony about HGN, impairment by a certified DRE, and vehicle speed based on an accident reconstruction.
The Basic Rule
Rule 702 – Testimony By Experts
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(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) Notwithstanding any other provision of law, a witness 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 in accordance with the person's training 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, if the witness holds a current certification as a Drug Recognition Expert, issued by the State Department of Health and Human Services. […] (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. […] (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. |
G.S. 8C-702 (reformatted and abbreviated for relevance to criminal practice).
Legal Overview
Expert witnesses are permitted to testify and offer opinions about a wide range of facts and issues in a case. See generally State v. Fullwood, 323 N.C. 371 (1988), on remand, 329 N.C. 233 (1991). Rule 702 sets out the requirements to qualify a witness as an expert and to have the witness testify in the form of an opinion. See G.S. 8C-702(a). The relevant portions of Rule 702 are collected and reprinted in this entry for reference (omitting the portions that relate only to civil and medical malpractice cases). The legal issues pertaining to this rule are discussed in greater detail in other entries in this guide, as listed below.
Rule 702(a): Qualifications
An expert witness is one who is qualified by knowledge, skill, experience, training, or education and whose scientific, technical, or other specialized knowledge will assist the fact-finder to understand the evidence or determine a fact in issue. G.S. 8C-702(a).
For more information about the qualifications that are required in order for a witness to be tendered as an expert under Rule 702(a), see the related Expert Testimony entry on Basic Guidelines.
Rule 702(a)(1)-(3): Foundation
A properly qualified expert may testify in the form of an opinion, but only if that opinion is: (1) based on sufficient facts or data; and (2) the product of reliable principles and methods; which were (3) reliably applied to the facts of the case. G.S. 8C-702(a)(1)-(3).
For more information about the necessary foundation to introduce an expert’s opinion under Rule 702(a)(1)-(3), see the related Expert Testimony entry on Reliability, Admissibility, and Daubert.
Rule 702(a1): HGN/DRE
A witness may give expert testimony on the issue of impairment, but not a specific alcohol concentration level, regarding the results of a Horizontal Gaze Nystagmus (“HGN”) Test if the witness was trained in its administration and administered the test in accordance with that training. G.S. 8C-702(a1)(1). A witness currently certified as a Drug Recognition Expert (“DRE”) may give expert testimony regarding whether a person was under the influence of an impairing substance and the category of that substance. G.S. 8C-702(a1)(2). A DRE may not testify to a specific alcohol concentration. G.S. 8C-702(a1).
For more information about offering expert testimony regarding the Horizontal Gaze Nystagmus (“HGN”) Test under Rule 702(a1), see the related Expert Testimony entries HGN: Law and Issues and HGN: Suggested Questions.
For more information about offering expert testimony from a Drug Recognition Expert (“DRE”), see Shea Denning, “State v. Fincher: No Foundation Required for DRE Testimony,” N.C. Criminal Law Blog, April 18, 2018.
Rule 702(g): Other Grounds
The fact that a witness satisfies the criteria to testify as an expert under Rule 702 does not bar the court from disqualifying the witness on any other grounds. See G.S. 8C-702(g).
For more information about the court’s ability to disqualify any witness on other grounds such as competency, see the related Trial entry on Examination of Witnesses: Overview, Competency, and Qualifications.
For more information about excluding the expert’s testimony on the grounds of prejudice, confusion, or waste of time, see the related Evidence entry on Prejudice, Confusion, Waste of Time [Rule 403].
If the “other grounds” for exclusion are based on the expert witness’s unavailability or confrontation clause issues, see the related Expert Testimony entry on Crawford and Substitute Analysts.
Rule 702(i): Accident Reconstruction/Speed
A witness qualified as an expert in accident reconstruction who has performed a reconstruction or reviewed reports about the investigation may offer an opinion about the speed of a vehicle involved in the collision. See G.S. 8C-702(i); see State v. Hazelwood, 187 N.C. App. 94, n.1 (2007) (noting that as of December 1, 2006, the enactment of Rule 702(i) reversed the common law rule that said neither a lay nor expert witness could testify as to vehicle speed if the witness did not personally observe it in motion).
For more information about offering expert testimony regarding accident reconstruction and vehicle speed under Rule 702(i), see the related Expert Testimony entry on Accident Reconstruction.
