The past hundred years has seen a shift from the use of statistics as support for what is essentially a nonstatistical case to the use of statistics as the only way to demonstrate what is wrong. Although Muller v. Oregon (1908) is recognized as the case which introduced social science argument into litigation, the 1953 Brown decision is considered the culmination of social science as legislative fact. There are four areas in which social science is used in the courts: antitrust, procedural aspects, evaluation of harm done, and determination of adjudicative fact (class action). The courts are receiving and applying analytic method as direct factual proof. In class action suits, the focus of court action remains centered on the individual, but the shift to class actions and statistical proofs reflects a change in the nature of individual actions that the government intends to regulate. Although class action suits represent less than 3 percent of all Federal filings, the percentage is growing. Ten well known cases involving statistical proof of adjudicative fact are discussed, and the pertinent literature is cited.