Section 705. Disclosure of Facts or Data Underlying Expert Opinion

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.

NOTE

This section is taken nearly verbatim from Proposed Mass. R. Evid. 705, which the Supreme Judicial Court adopted in Department of Youth Servs. v. A Juvenile, 398 Mass. 516, 532, 499 N.E.2d 812, 821 (1986).

“The rule is aimed principally at the abuse of the hypothetical question. It does not eliminate the availability of the hypothetical question, but only the requirement of its use. . . . The thrust of the rule is to leave inquiry regarding the basis of expert testimony to cross-examination, which is considered an adequate safeguard.”

Id., quoting Advisory Committee’s Note on Proposed Mass. R. Evid. 705. See Commonwealth v. Jaime, 433 Mass. 575, 577–578, 745 N.E.2d 320, 322 (2001) (“Taking the rule and its rationale into consideration, permitting the expert to offer the contested hearsay testimony on direct examination constituted error. The judge should have sustained the defendant’s objection and precluded the admission of hearsay statements irrespective of whether they formed the basis of the expert’s opinion. If he had sought to, of course, defense counsel could have cross-examined [the expert] about the facts underlying his opinion.”). Accord Commonwealth v. Nardi, 452 Mass. 379, 387–395, 893 N.E.2d 1221, 1228–1234 (2008). In Commonwealth v. Barbosa, 457 Mass. 773, 785–787, 933 N.E.2d 93, 106–108 (2010), the Supreme Judicial Court stated the direct examination of an expert on facts not in evidence

“is limited to the expert’s opinion and matters of which the expert had personal knowledge, such as her training and experience, and the protocols generally accepted in her field of expertise. Only the defendant can open the door on cross-examination to testimony regarding the basis for the expert’s opinion, which may invite the expert witness to testify to facts or data that may be admissible in evidence but have not yet been admitted in evidence.”

Accord Commonwealth v. Leng, 463 Mass. 779, 783–785, 979 N.E.2d 199, 205 (2012); Commonwealth v. Nardi, 452 Mass. 379, 387–395, 893 N.E.2d 1221, 1228–1234 (2008).

Cross-Reference: Article VIII, Introductory Note.

Limitation on Cross-Examination. Under certain circumstances, the requirement that the expert disclose underlying facts or data on cross-examination may be limited by Section 403 considerations. See Commonwealth v. Anestal, 463 Mass. 655, 668–669, 978 N.E.2d 37, 47–49 (2012). In Anestal, the court held that

“[o]nce the Commonwealth sought to inquire over objection about this prior bad act evidence, it was incumbent on the judge in the sound exercise of his discretion to ascertain whether the evidence was probative and, if so, whether that probative value was substantially outweighed by the danger of unfair prejudice to the defendant.”

Id. at 669, 978 N.E.2d at 48. This inquiry should take place at sidebar, or the judge should conduct a voir dire. Id. at 669 n.20, 978 N.E.2d at 49 n.20.