In most endeavors concerned with the acquisition of knowledge, quantitative information is welcomed. In law, however, it appears sometimes that scientific or numerical evidence makes cases harder, not easier. Nevertheless, there are many cases and administrative proceedings, in such areas as environmental law, food and drug regulation, and civil rights, in which statistical data obtained by observation or experiment are readily accepted as assisting in the proper resolution of disputed issues of fact. When courts or administrators confront scientific and statistical evidence in these proceedings, they are not always certain of how to weigh the evidence or whether they should or must rely on the standards for proof that scientists apply in evaluating statistical hypotheses.

In any case involving statistical proof, the proponent of the evidence understandably covets testimony that the data is significant. Although there are grounds to question whether such testimony to significance should even be admissible, this article confines to one issue - the relationship between the putative scientific standard of proof and the legal standards of proof.