Opinion ID: 202396
Heading Depth: 2
Heading Rank: 3

Heading: Necessity of Expert Testimony

Text: 20 Finally, the Beaudettes challenge the district court's finding that expert testimony is required for their claim of inadequate warnings. In a diversity action, whether expert testimony is required is a matter of state law. See Hochen v. Bobst Group, Inc., 290 F.3d 446, 451 (1st Cir.2002) (applying Massachusetts state law to determine whether expert testimony was required to prove a design or manufacturing defect). The New Hampshire Supreme Court has held that [e]xpert testimony is required . . . to aid the jury whenever the matter to be determined is so distinctly related to some science, profession, business or occupation as to be beyond the ken of the average layman. Estate of Joshua T. v. State, 150 N.H. 405, 840 A.2d 768, 771 (2003) (internal quotation marks omitted). 21 Under New Hampshire law, the question of whether it would be prudent to include specific warnings regarding the use of a common household object may be beyond the ken of the average person. For example, in Lemay v. Burnett, the New Hampshire Supreme Court affirmed the trial court's dismissal of a failure to warn case where the plaintiff had failed to designate an expert on swimming pools. 139 N.H. 633, 660 A.2d 1116 (1995). In that case, the plaintiff was injured while diving into a backyard swimming pool and claimed that the homeowner should have provided warnings as to the risk of diving into a pool. The New Hampshire Supreme Court affirmed the case, noting that while a juror may be generally familiar with swimming pools, the average juror could not know what particular combination of conditions—including water depth, height of the diving board, or the stiffness of the diving board—could lead to reasonably safe diving conditions for a man of the plaintiff's size. Id. at 1116-18. 22 We find it clear that, under New Hampshire law, expert testimony is required for the Beaudettes' failure to warn claim. Although the average juror may have experience with ladders, the average juror will not have knowledge as to the use of a ladder jack, the construction of scaffolding out of ladders, and the combination of factors that would make such a situation safe or unsafe. Consequently, the district court did not err in requiring expert testimony to sustain the Beaudettes' claims for failure to warn.