If some courts have been using unduly constrained, idealized, or overly simple heuristics for reviewing scientific testimony on causation, how might they conduct this task differently? How can they better address complex patterns of evidence? Can their admissibility decisions better serve the aims of both law and science?

One route to improve reviews of expert testimony would be for judges to use court-appointed experts; I briefly consider this idea. A likely better approach (because of the costs) is for courts to follow the lead of the First Circuit Court's Milward v. Acuity Products that in turn is anchored by the Supreme Court's Kumho Tire and Daubert v. Merrell-Dow Pharmaceutical decisions. To give scientific content to this second idea, one should understand more nuanced patterns of evidence from consensus scientific committees. These illustrate varieties of studies and complex patterns of evidence that scientists have utilized. Courts should be able to recognize and assess a wider range of evidentiary patterns than some have previously. I consider a few legal cases other than Milward in which judges have recognized the subtlety of issues they faced or in which they addressed well the shortcomings of studies or reasoning with which they were faced. Toward the end of the chapter, I revisit a few decisions discussed in Chapter 1 to illustrate in view of subsequent chapters more specifically some of the problems they raise.

Courts can choose how they implement Daubert and its progeny. They could unduly restrict scientific testimony, or fail to recognize more subtle scientific mistakes that can affect litigants. In contrast, they could better utilize scientific evidence and more closely follow the science than they have in the past, by reviewing scientific testimony with Milward v. Acuity Specialty Products as a model to assess whether testimony falls within a “zone where experts might reasonably differ” (following Kumho Tire). Were they to do this, it is reasonable to expect several consequences to result.

Expert testimony would be better founded in science than at present and comport better with how scientists themselves assess evidence. This would likely increase the acceptability of admissibility decisions within the scientific community and reassure respectable scientists who testify that their testimony will not be judicially condemned as inadequate.