The Daubert standard directs federal trial judges to act as gatekeepers over expert testimony, assessing whether the expert's methodology is scientifically reliable and properly applied to the facts of the case, not just whether the expert is generally credentialed. Factors commonly considered include 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 error rate, the existence of standards controlling its application, and whether it is generally accepted in the relevant field.

The gatekeeping role applies to the expert's reasoning and methodology, not merely their conclusions — a well-credentialed expert applying an unreliable method can still be excluded, and a properly applied reliable method can support testimony even from a less prominent expert. Challenges are typically raised through a pretrial motion to exclude, and losing this gatekeeping fight can eliminate a claim's central proof before trial even begins.

Juricratic frames expert-driven inputs — damages models, causation theories, technical opinions — as operator outputs that must disclose their method, assumptions, and known limitations, echoing the same reliability transparency Daubert requires of a testifying expert, so a simulated case never treats an expert conclusion as bare, unexamined fact.

Litigators use Daubert motions offensively to exclude an opposing expert whose methodology is shaky, and defensively by building a thorough methodological record — testing, peer-reviewed support, error rates — before their own expert is ever deposed. Surviving a Daubert challenge is often a make-or-break moment in cases that turn on technical or scientific proof, such as product liability, patent, or complex damages disputes.