Expert Witness
Definition
An expert witness is a person qualified by knowledge, skill, experience, training, or education to testify in the form of an opinion on matters beyond the understanding of a layperson. Under Federal Rule of Evidence 702 and Daubert v. Merrell Dow Pharmaceuticals, the trial judge acts as a gatekeeper, ensuring expert testimony is based on sufficient facts, is the product of reliable principles and methods, and the expert has reliably applied those methods to the facts. Kumho Tire extended Daubert's gatekeeping function to all expert testimony, not just scientific evidence.
Example
A forensic accountant testifies about complex financial fraud. The court must determine under Daubert that the accountant's methodology is scientifically valid and properly applied.