In some circumstances, a plaintiff lacking direct evidence of an identifiable, specific defect may be permitted to use circumstantial evidence to prove that a product malfunctioned and create a triable inference of a product defect. Some courts may treat proof of a product malfunction as circumstantial evidence of a product defect because a product will not ordinarily malfunction (or perform outside the reasonable safety expectation of the consumer) in the absence of a defect. This circumstantial evidence doctrine, commonly known as the “malfunction theory,” may provide plaintiffs with a pathway to establish a prima facie case of a product defect.

While the malfunction theory sometimes allows plaintiffs to bring a claim for a product defect where the product is no longer available or a specific defect cannot be identified, plaintiffs often attempt to stretch the theory beyond its logical bounds. In a recent case from Idaho, Black v. DJO Global, Inc., the Idaho Supreme Court rejected use of the malfunction theory when the alleged product “failure” (or malfunction) was the occurrence of a known risk, i.e., one that could occur even when the product performs as intended. Black v. DJO Glob., Inc., 488 P.3d 1283, 1288 (Idaho 2021).

Continue reading “A Bridge Too Far: Reliance on Malfunction Theory Rejected When the Alleged Failure is a Known Risk of the Product”