A “Daubert Challenge” generally means a request to exclude a potential expert’s testimony. In most courts, an expert is one who possesses knowledge, skill, experience, training, or education and testifies in the form of an opinion about scientific, technical, or other specialized knowledge.
There are five important considerations. First, the evidence must be scientific, technical, or otherwise specialized. Second, the evidence must be knowledge, not just subjective belief. Third, the evidence must be relevant to the case. Fourth, the evidence must be of a type reasonably relied upon by experts in the particular field in forming opinions. Fifth, the evidence must be reliable. When assessing reliability, courts assess whether the (a) opinions are subject to testing, (b) whether they have been submitted to peer review and publication, (c) potential error rates, and (d) whether the technique is generally accepted in the scientific community.
Importantly, this is a flexible inquiry. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 594 n. 12 (1993). Courts almost must generally resolve doubts regarding these considerations in favor of the admission of the expert testimony. Johnson v. Mead Johnson & Co., LLC, 754 F.3d 557, 562 (8th Cir. 2014).