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Sixth Circuit Tackles Insufficient Expert Testimony in Litigation

publication | August 27, 2025

Hollingsworth LLP partner David Schifrin authored an article for Bloomberg Law, in which he discusses how the Sixth Circuit’s recent decision in Buchanan v. Johnson & Johnson Consumer, Inc. reminds us that separate and apart from the question of admissibility, plaintiffs must establish that their experts’ opinions are sufficient to create a genuine dispute of material fact from which a jury could find in favor of the plaintiff.

Plaintiff Cyndi Buchanan brought claims against Johnson & Johnson alleging that its OGX shampoo and conditioner products caused her hair loss. In support of her claim, she offered the expert testimony of Dr. Robert Schwartz, a dermatologist. However, Schwartz refused to testify that the shampoo and conditioner were a cause or substantial contributing factor of plaintiff’s hair loss. Johnson & Johnson challenged Schwartz’s opinions as inadmissible under Rule 702, but it separately argued the opinions in any event weren’t sufficient to meet plaintiff’s substantive burden of proof to establish causation.

Without admissible expert testimony on causation in a case in which expert testimony is required, a plaintiff cannot meet their burden of proof to avoid summary judgment. Because Schwartz did not do so, the district court granted summary judgment to Johnson & Johnson based on the insufficiency of plaintiff’s evidence. The Sixth Circuit affirmed the district court’s grant of summary judgment, correctly noting that Schwartz’s speculative testimony was insufficient to create a genuine dispute of material fact on causation under Federal Rules of Civil Procedure 56.

In addition to providing a reminder of a plaintiff’s independent obligation to proffer expert testimony that is sufficient to establish causation, the Sixth Circuit highlights potential choice-of-law questions that could arise when a defendant challenges the sufficiency of the evidence under FRCP 56. Although the court declined to answer these questions, the court’s comments indicate a willingness to take a closer look at these potential conflict-of-law issues in ways that could be determinative in other litigation.

Access the story at Bloomberg Law.