CONSEQUENCES OF MORE-WATCHFUL GATEKEEPING
The previous three sections describe indications we found that judges have become morewatchful gatekeepers for expert evidence since Daubert. These findings suggest that standards for reliability have tightened and that judges have examined challenged evidence more carefully with respect to other criteria as well. This section examines some of the consequences of this enhanced scrutiny. We first examine its effect on the proportion of challenged evidence excluded; we then examine its effect on one possible outcome when evidence is excludedsummary judgment. Finally, we examine changes in the types of evidence challenged.
Table 7.1 shows the proportion of challenged expert evidence excluded when the evidence is found lacking in terms of reliability, relevance, qualifications, or other considerations. As can be seen, evidence rated negatively on any one of these criteria is almost always excluded, both prior to and after Daubert. Trends in the proportion of challenged evidence found lacking on the basis of one or more criteria thus closely mirror trends in the proportion of challenged evidence excluded.
Table 7.2 shows that slightly over one-half of the 601 challenged elements of evidence in our sample were excluded overall (see Raw Date columns).1 When case type, substantive area of evidence, and appellate circuit are held constant, the proportion of challenged evidence rises after Daubert and then falls (see last column of Table 7.2 and see Figure 7.1).2 The pattern mirrors the patterns for the proportion of evidence found unreliable (see Table 4.1) and for the proportions of evidence rated unfavorably on relevance and on expert qualifications (see Table 6.1).____________________