Rule 2:703.BASIS OF EXPERT TESTIMONY (Rule 2:703(a) derived from Code § 8.01- 401.1)

Rule 2:703 addresses what raw material an expert may draw on in forming an opinion, and treats civil and criminal cases differently. In a civil action, subdivision (a) allows an expert to testify and render an opinion, or draw inferences, from facts, circumstances, or data made known to or perceived by the expert at or before the hearing or trial. The key allowance follows: if that underlying material is of a type normally relied upon by others in the expert’s particular field when forming opinions and drawing inferences, it need not itself be admissible in evidence for the expert to rely on it.

That civil-case allowance lets experts function the way they do in their own professions — a physician relying on a colleague’s notes, a nurse’s report, or an x-ray reading by another practitioner, none of which the physician necessarily witnessed firsthand or could independently authenticate as admissible evidence — as long as that kind of reliance is normal practice within the field.

Criminal cases follow a narrower rule. Subdivision (b) makes an expert’s opinion generally admissible if it rests on facts the expert personally knew or observed, or on facts already in evidence. That formulation does not extend the civil rule’s allowance for inadmissible, field-standard material — the expert’s foundation in a criminal case stays tied to personal knowledge or the trial record itself.