Expert Article Library

Experts in Product Liability Must Provide Details in Their Findings

Case Name: Wagner v. Hesston Corp. (Click here for the full text of the case)

Court: 8th Circuit Court of Appeals

Date: June 8, 2006

Expert: Experts in the design of agricultural products. John Sevart and Jonathan Chaplin

Issue: Whether the plaintiff’s proposed expert testimony was deficient because of lack of peer review, actual testing and acceptance in the industry

Summary of case: The plaintiff lost his hand in a hay baler that had become jammed. After the hand was amputated he sued the manufacturer under product liability alleging defective design and manufacture.

Role of the expert: John Sevart and Jonathan Chaplin concluded that the hay-baler should have had (1) a safety guard, (2) an emergency stop device, and (3) and an “open throat” design, instead of the “compression roller” design.

Challenges to the Expert's testimony: The defendant disputed the relevance and reliability of the plaintiff’s expert testimony. The District Court ruled that Sevart and Chaplin’s opinions were not reliable and excluded them from the case. The Court of Appeals noted that neither expert adequately tested his opinion regarding the proposed safety guard; there was no evidence offered to show that an “open throat” design of a hay baler produced the same quality of bales as the compression roller design; and that there was no evidence showing that even if there was an emergency stop device, it would have allowed the plaintiff to prevent the compression rollers from grinding his hand and arm. The Court of Appeals held that the District Court properly excluded the expert testimony as unreliable.

Summary prepared by M. Lanzone, Student, University of California, Hastings College of Law