TRENDS IN FACTORS ENTERING INTO THE RELIABLITY ASSESSMENT
This section delves into the factors judges use to evaluate whether evidence is reliable. We examine changes over time in the factors discussed in written opinions and in how challenged evidence measures up against these factors, We use the findings to make inferences about how judges are assessing reliability and the importance of general acceptance in their evaluations. Our findings suggest that judges are increasingly examining the clarity and coherence of an expert's explanation of the theory, method, and procedures underlying his or her findings and that general acceptance has, if anything, increased in importance since Daubert.
We start by defining the reliability factors used in our analysis. We then examine how often these factors are addressed in written opinions and how often challenged evidence falls short on each factor. We conclude by exploring how the importance of general acceptance has changed since Daubert.
We assembled a list of factors that might be germane to assessing whether evidence is reliable. We based the list on reviews of federal district court, appellate, and Supreme Court opinions; law review articles; briefs written by scientific organizations for the Daubert case; and other books and articles on science in the courts.
Table 5.1 presents the list, along with some clarifying comments. The first five factors listed are those that the Supreme Court gave in the Daubert opinion as examples of factors judges should take into account when assessing reliability. The Court did not require, however, that these five factors be considered in every situation or prohibit other factors from being considered.
For each of the 601 elements of evidence in our sample, the coders recorded which reliability factors were discussed and whether the judge rated the evidence favorably, unfavorably, or neither favorably or unfavorably on each factor.1 As before, the frequency with which a factor is addressed likely reflects challengers' decisions to challenge evidence on that basis. The proportion of evidence rated unfavorably on a factor reflects both the frequency with which the evidence is questioned on that factor and the standards applied by judges in evaluating the evidence on that factor.____________________