Daubert v. Merrell Dow Pharmaceuticals, Inc.

Two children born with birth defects sued the maker of Bendectin. Their experts' causation opinions rested on reanalyses that had not been published or generally accepted, and the lower courts excluded them under Frye v. United States, which conditioned admissibility on general acceptance in the relevant field. The question was whether Frye survived the enactment of the Federal Rules of Evidence — and if not, what standard Rule 702 imposes instead.

Frye's general-acceptance test was superseded by the Federal Rules. Under Rule 702 the trial judge must make a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and can properly be applied to the facts. The inquiry is flexible; the factors the Court identified are whether the theory or technique can be and has been tested, whether it has been subjected to peer review and publication, its known or potential rate of error and the existence of controlling standards, and its degree of acceptance — the last now one factor among several rather than the whole test.

The Court declined to apply its new standard itself, vacating and remanding for the Ninth Circuit to assess the reanalyses under Rule 702. It answered the losing argument directly: screening does not usurp the jury, because vigorous cross-examination, contrary evidence, and careful instruction remain the traditional means of attacking shaky but admissible evidence — while the gatekeeping role accepts that keeping some genuine insights out is the price the Rules of Evidence pay for resolving particular disputes rather than pursuing cosmic understanding.

Judgment vacated and remanded. On remand the Ninth Circuit excluded the experts again under the new standard, but the remand was a footnote to the holding: every federal expert — and, after Kumho Tire, every technical expert as well — now testifies only after a judge has examined the reliability of the method. Rule 702 was amended in 2000 and again in December 2023 to codify and sharpen the gatekeeping this opinion created.