In 1993, the U.S. Supreme Court in Daubert v. Merrell Dow Pharmaceuticals, Inc., laid out a new test for federal trial judges to use when determining the admissibility of expert testimony. In Daubert, the Court ruled that judges should act as gatekeepers, assessing the reliability of the scientific methodology and reasoning that supports expert testimony. The resulting judicial screening of expert testimony has been particularly consequential. While the Supreme Court sought to bring better science into the courtroom, questions remain about whether the lower courts’ application of Daubert accords with scientific practices. This report summarizes discussions held by an ad hoc committee of the The National Academies to consider the impact of Daubert and subsequent Supreme Court opinions and to identify questions for future study.