Scientific evidence is an inescapable facet of modern litigation. It is fundamental to criminal justice and to civil litigation. What counts as science, however, who gets to make this decision, and how they should go about it are all hotly contested. Nor is this contest limited to the United States. The issue of scientific reliability is a hot topic in England and other Commonwealth jurisdictions, as well as in continental European systems.

In the United States, legislatures, federal, and many state courts have placed the responsibility for evaluating the validity of scientific testimony squarely on judges. Other states continue to use a general-consensus standard for scientific validity, in which it is the scientific community that makes that decision. In those jurisdictions where judges must evaluate scientific validity, the result is that judges – traditionally triers of law, occasionally pressed into service as triers of fact – now must also be triers of science in cases where experts proffer scientific evidence.

Predictably, not everyone is pleased with this new state of affairs, and many question judicial competence in this area. Years after Daubert v. Merrell Dow Pharmaceuticals, Inc. and the subsequent amendments to the Federal Rules of Evidence made federal judges responsible for assessing scientific validity, judges and lawyers are still grappling with the fact that they can no longer merely count scientific noses but must instead analyze whether expert testimony meets the criteria of good science.