A recent decision from the Commonwealth Court of Pennsylvania does a nice job of addressing some common challenges to whether expert opinion testimony from an actuary should be admitted. Glaze v. Workers’ Comp. Appeal Bd. (Pa. Commw. Ct., 2012). In the case, the court was reviewing challenged actuarial evidence used to support the value of pension contributions to a defined benefit plan. The court rejected claims that actuarial testimony had to be mathematically certain:
[T]he proper inquiry is not whether some information may differ, but whether the use of the information is justified and acceptable within a reasonable degree of actuarial certainty. As to defined-benefit plans and expert testimony in general, case law does not require certainty. See, e.g., Lach v. Fleth, 361 Pa. 340, 64 A.2d 821 (1949) (expert opinion in claim for damages is sufficient if it affords a reasonably fair basis for calculating the plaintiff’s loss; it need not conform to the standard of mathematical exactness).
It’s a common strategy of a party challenging actuarial evidence to poke at the underlying data and argue that any data issues must result in all the related testimony being discarded. The court in Glaze recognized that the test should be whether the data is of sufficient quality that an actuary can render an opinion “to a reasonable degree of actuarial certainty.”