Method to the Madness: Tips for Separating Lay Opinion Testimony from Expert Testimony

The Federal Rules of Evidence permit experts to provide opinions based on “scientific, technical or other specialized knowledge.” Many witnesses have “specialized knowledge” in a sense. The witness to a car accident, for example, will have knowledge about the accident that other people may not. But not all witnesses are deemed experts, and experts are not the only witnesses who may provide opinions. The distinction between expert and lay opinion testimony can determine whether a witness is deemed competent, the timing and content of required disclosures, and a party’s ability to meet the burden of proof. This article examines the sometimes-nebulous line between the two forms of opinion testimony.