Demonstrative Evidence

Abstract Most expert witnesses have occasion to use demonstrative evidence, which is not to be considered substantive proof of a fact, but is used solely to supplement, explain, or clarify the witness's testimony. Many do not understand exactly what the legal definition of demonstrative evidence is. This article categorizes the various items that fall into what courts call demonstrative evidence. It also touches on the circumstances under which its court use is permitted. In that regard it is important to stress that judges possess considerable discretion in making the decision whether to admit what they consider to be demonstrative evidence.