The role of the expert witness: an update

As in the past, the principle role of the scientist in the courtroom is to assist attorneys, judges, and jurors in understanding the complex scientific and technical issues before them. In the last decade, however, changes in the law and the increasing technical complexity of many disputes have introduced new factors that influence the preparation and presentation of expert testimony. The most significant change in the law regarding expert testimony is arguably the 1993 Supreme Court ruling in Daubert vs. Merrell Dow Pharmaceuticals. Under Daubert, scientific evidence may be submitted to the jury if the judge finds that it rests on a reliable foundation and is relevant to the task at hand. Reliability and relevance replace the older requirement of "general acceptance by the scientific community," although "general acceptance" remains a factor in the consideration of reliability. The tests of reliability and relevance and their impact on the preparation of expert opinions are discussed in the context of increasingly complex radiation cases, with emphasis on cases involving teams of experts.