Daubert v. Merrell Dow: The Supreme Court Rewrote Expert Testimony Rules

Jason Daubert and Eric Schuller were born with serious limb reduction defects. Their parents believed the cause was Bendectin — an anti-nausea drug made by Merrell Dow Pharmaceuticals that their mothers had taken during pregnancy. They filed suit. Merrell Dow's expert testified that over 30 published epidemiological studies showed no increased risk of birth defects.

The plaintiffs had their own experts — but those experts' analyses had not been published in peer-reviewed journals.

The case reached the Supreme Court. What happened next transformed American law.

THE QUESTION: Under the Frye standard, Merrell Dow argued the plaintiffs' experts' methodology lacked "general acceptance." The trial court agreed and granted summary judgment. The Ninth Circuit affirmed.

The Supreme Court took the case to determine how courts should evaluate the admissibility of expert scientific testimony.

THE RULING: On June 28, 1993, Justice Harry Blackmun wrote for a 7-2 majority. The Court held that the Federal Rules of Evidence — not the Frye "general acceptance" test — governed admissibility. Judges were to act as "gatekeepers," using a flexible set of factors to assess reliability:

• Has the theory been tested?
• Has it been subject to peer review?
• What is the known or potential error rate?
• Is it generally accepted in the relevant scientific community?

THE IMPACT: Daubert placed greater responsibility on trial judges to evaluate the scientific basis of expert testimony. Critics argued this turned judges into untrained scientists. Supporters argued it created a more rigorous, evidence-based standard.

The ruling has been invoked thousands of times in subsequent cases — in product liability, criminal trials, and civil litigation — to exclude or admit expert evidence.

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