By Derek Stikeleather

When challenging an expert’s causation opinion that contradicts peer-reviewed medical literature under Rule 5-702(3), does the movant need to provide an affidavit from its own expert to explain the inconsistency between the literature and the challenged opinion? No.

Rule 5-702 does not require an expert affidavit for a court to consider relevant medical or other peer-reviewed scientific literature when ruling on the admissibility of expert testimony. Instead, it is a matter of counsel’s judgment (and possibly budget) to consider whether a competing expert affidavit would help show the court that the challenged opinion is unreliable and inadmissible under Rule 5-702. Although a good expert’s affidavit is often helpful, it might over-complicate some proceedings by opening a prolonged and distracting “battle of the experts.”

Sometimes, professional peer-reviewed literature speaks for itself and most effectively rebuts the challenged opinion on its own. Judges, as “gatekeepers,” do not require expert affidavits to walk them through such literature. But dicta from a recent Court of Appeals opinion, Frankel v. Deane[i], seems to suggest otherwise. This could lead some courts to invent a nonexistent expert-affidavit requirement under Rule 5-702.