Daubert v. Merrell Dow Pharmaceuticals

The court’s reasoning

Rule 702 contains no general-acceptance requirement, and a rigid one would conflict with the liberal thrust of the Rules. In its place the Court assigned the trial judge a gatekeeping duty to confirm that expert testimony rests on a reliable foundation and fits the facts in issue, listing testability, peer review and publication, known or potential error rate, standards controlling the technique's operation, and general acceptance as non-exclusive factors. The inquiry is flexible and focuses on principles and methodology rather than the conclusions they generate.

From the opinion

“the Rules of Evidence — especially Rule 702 — do assign to the trial judge the task of ensuring that an expert's testimony both rests on a reliable foundation and is relevant to the task at hand.”

Grounds argued

This ruling turned on 2 of the eight arguments that recur across the docket. Each is defined the same way on every entry, so the same ground can be followed across rulings that reached opposite results.

Methodology

Whether the steps the examiner took are a recognised way of answering the question asked, and whether they were followed as described. Most digital-forensics rulings turn on this rather than on anything the field would call science.

Fit to the issue

Whether the opinion helps decide a fact actually in issue. Testimony can be entirely reliable and still be excluded because it answers a question the case does not ask.

Practice note

Terms used on this page

Every term below is defined in the forensic glossary — what it is, why a case turns on it, and what happens in the matter when it is mishandled.

• DAUBERT STANDARD
• FRE 702
• FRYE STANDARD

Rulings on the same grounds

One ruling is not a rule. These are the other entries in the docket argued on the same grounds, most-cited first — including the ones that came out the other way, which are the ones worth reading before relying on this entry for anything.

• The Daubert Docket

  All 55 rulings, filterable by ground, outcome and court, with the distribution across the three outcomes reported up front.

• Daubert and digital evidence

  The argument this docket is the evidence for: why an opinion stated one level too strongly is an admissibility problem under Rule 702(d).

• Daubert Exposure Check

  Twelve questions about an expert's methodology, mapped to the failure modes these rulings keep finding, with the remediation for each gap.

• Daubert or Frye?

  Which reliability test your forum applies — settle that before relying on a ruling from another jurisdiction.

← BACK TO THE DAUBERT DOCKET

Attorney advertising / expert services. Each entry summarises a decision as it appeared in the opinion linked from that entry, on the day the entry was written. Decisions are reversed, vacated, superseded, and distinguished, and the text of Federal Rule of Evidence 702 was itself amended effective 1 December 2023 — check the current status and subsequent history of any ruling before relying on it. Nothing here is legal advice, none of it is a prediction about how any court will rule, and it is not a substitute for the rules, standing orders and case law of your own forum.