Expert Article Library

Biomechanical Expert's Speculation as to Accident Causation Ruled Inadmissible

Case Name: O'Neill v. Windshire-Copeland Assocs., L.P. (Click here for the full text of the case)

Court: United States Court of Appeals for the 4th Circuit

Date: June 16, 2004

Expert: Biochanical Expert. Dr. David A. Thompson, Professor of Biomechanics

Issue: The admissibility of a biomechanical expert’s opinion as to “how and why” an accident happened.

Summary of case: Plaintiff was leaning against a railing on a second-floor apartment balcony. She fell over backwards and hit the ground. She sued the landlord for negligence per se because the railed was not as high as the building code mandated. The defendant landlord alleged contributory negligence (which would preclude plaintiff from recovery) because plaintiff had been drinking. Plaintiff introduced a biomechanical expert who gave his opinion on the cause of the accident. The lower court ruled his testimony inadmissible.

Role of the expert: Dr. Thompson testified that a heavy gust of wind probably caused O’Neill’s fall. He wrote a report describing the amount of force various wind-levels would create on O’Neill’s upper torso. He also determined where O’Neill’s center of gravity was in relation to the height of the railing when she leaned on it.

Challenges to the Expert's testimony: The 4th Circuit ruled that the lower court did not abuse its discretion in ruling the testimony inadmissible. Citing Cooper v. Smith & Nephew, Inc., the court ruled expert opinion cannot be based on “belief or speculation.”

Summary prepared by C. Wood, Student, University of California, Hastings College of the Law