The growing complexity of federal courts’ dockets and continuing political controversy surrounding tort litigation have highlighted the importance of trial judges’ treatment of scientific expert testimony. While federal trial judges have been empowered for over a century to determine the conditions under which certain kinds of evidence would be deemed admissible, the United States Supreme Court’s ruling in Daubert v. Merrell Dow Pharmaceuticals (1993) refined and redefined the trial judge’s responsibility to determine whether expert scientific evidence is suitable for presentation to a jury. In Daubert, the Supreme Court reaffirmed the trial judge’s role as a gatekeeper responsible for scrutinizing such evidence, and it specified certain guidelines that would inform judges’ decisions about admissibility. These guidelines supplanted the previous rule that admissibility decisions would hinge on whether the scientific technique underpinning an expert’s testimony was "generally accepted" as reliable in the relevant scientific community (the Frye test). Daubert was influential in several ways. It sparked a contrast between the judicial gatekeeping function with regard to scientific expert testimony, and the general preference of the Federal Rules of Evidence--Rule 702 in particular--to admit potentially relevant evidence. It also increased the judge’s role, at the expense of the jury’s, in determining admissibility. Furthermore, the expanded gatekeeping role set forth in Daubert placed additional demands on trial judges, who as a group lack specialized expertise concerning the scientific component of the disputes being adjudicated. What has been less clear is whether Daubert has made trial judges less willing to admit scientific expert testimony. Daubert stressed the need for judges to make independent assessments of the quality of the expert’s scientific evidence, and some observers (see, e.g., Faigman et al. 2000) have argued that judges subsequently defer to experts less than they did when the Frye standard of scientific consensus determined admissibility. At the same time, however, Daubert’s mandate might open the courthouse doors to theories and methodologies that are too new or too specialized to have been peer-reviewed or otherwise subjected to the scientific community’s scrutiny (Fenner 1996). As such, Daubert could have a liberalizing effect. This paper will determine what effect, if any, Daubert has had on federal trial judges’ willingness to admit scientific expert testimony. To test the expectation that Daubert has had some effect, I will perform a logit analysis of federal district judges’ admissibility rulings in tort cases following Daubert and preceding Daubert by ten years. The analysis will control for judges’ ideology (measured by the party of the appointing president), litigant characteristics, and, to determine whether strategic considerations have affected trial judges’ decision making, likelihood of reversal by an appellate panel (measured by the probability that a randomly selected three-judge panel will have a majority sharing the trial judge’s partisan affiliation). This design enables me to isolate any effects produced by the change in legal doctrine in Daubert. [ABSTRACT FROM AUTHOR]