## Facts

- Parents sued a drug manufacturer alleging that prenatal ingestion of Bendectin caused their children’s serious birth defects.
- The manufacturer sought summary judgment and offered an expert affidavit, based on a review of published scientific literature, stating Bendectin had not been shown to increase the risk of human birth defects.
- Plaintiffs offered expert opinions asserting causation, relying on animal studies, chemical-structure analyses, and an unpublished reanalysis of previously published human statistical studies.
- The district court excluded plaintiffs’ expert evidence under the Frye “general acceptance” test and granted summary judgment to the manufacturer.
- The court of appeals affirmed, treating general acceptance as a prerequisite to admissibility of scientific techniques.

## Issues

1. Whether the Federal Rules of Evidence, particularly Rule 702, displaced Frye’s “general acceptance” test for admitting expert scientific testimony in federal court.
2. What standard governs the admissibility of expert scientific testimony under Rule 702, including the trial judge’s role in evaluating reliability and relevance.
3. Whether the courts below applied the correct admissibility framework in excluding plaintiffs’ experts and entering summary judgment.

## Decision

- The Supreme Court held that the Federal Rules of Evidence, not Frye, supply the governing standard for admissibility of expert scientific testimony in federal trials.
- The Court ruled that Rule 702 assigns the trial judge a gatekeeping duty to ensure expert scientific testimony is both reliable and relevant to the dispute.
- The Court identified nonexclusive considerations bearing on reliability, including testability, peer review/publication, known or potential error rate and standards, and (as one factor) general acceptance.
- The Court vacated the judgment and remanded because the lower courts evaluated admissibility under Frye rather than the Federal Rules framework.

## Legal Principles

- Frye’s “general acceptance” requirement is not a necessary precondition to admissibility under the Federal Rules of Evidence.
- Under Fed. R. Evid. 702, expert scientific testimony must reflect “scientific knowledge,” meaning it must rest on scientifically valid reasoning or methodology rather than subjective belief or unsupported speculation.
- The trial judge must make a preliminary admissibility determination under Rule 104(a) that the expert’s methodology is reliable and that the testimony fits the facts at issue (helpfulness/relevance).
- Reliability is assessed flexibly; relevant considerations may include testability, peer review/publication, error rate and operational standards, and the degree of acceptance in the relevant scientific community.
- Even if Rule 702 is satisfied, evidence may be excluded under Rule 403 when its probative value is substantially outweighed by risks such as confusion or misleading the jury.
- Challenges to admissible expert evidence are ordinarily addressed through cross-examination, contrary evidence, and appropriate instructions on the burden of proof.

## Conclusion

The Court replaced Frye’s general-acceptance rule in federal court with a Rule 702 inquiry requiring judges to screen proffered scientific expert testimony for reliability and relevance through a flexible, nonexclusive set of considerations, and it remanded for application of that framework.


Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993)