Evidence: The Tactical Choice under Federal Rule of Evidence 703
Edward Imwinkelried
You can use a witness who happens to be an expert in several ways. For instance, the witness may testify to facts, express a lay opinion, or give the jury a lecture about a scientific theory or technique. However, the expert’s proponent usually wants the witness to do more, namely, to derive a relevant opinion by applying a general theory or technique to case-specific facts. While Federal Rule of Evidence 702 and Daubert, 509 U.S. 579 (1993), control the type of theory or technique the expert may rely on, Rule 703 governs the way in which the expert learns the case-specific facts.