The expert may testify in terms of opinion or inference and give reasons therefor without prior disclosure of the underlying facts or data, unless the court requires otherwise. The expert may in any event be required to disclose the underlying facts or data on cross-examination.

ADVISORY COMMITTEE NOTE

This rule is the federal rule, verbatim. The substance of this rule was formerly found in Rules 57 and 58, Utah Rules of Evidence (1971). The requirement that an expert disclose the underlying facts or data for his opinion when cross-examined was formerly found in Rule 58, Utah Rules of Evidence (1971). The discretion vested in the trial judge to require prior disclosure of underlying facts or data should be liberally exercised in situations where there has not been adequate discovery in civil cases or disclosure in criminal cases.