Steven Shavell, Any Frequency of Plaintiff Victory at Trial Is Possible, 25 J. Legal Stud. 493 (1996).
Abstract: A basic question about litigation concerns the frequency of plaintiff victory at trial and how cases that go to trial relate to settled cases. In a stimulating paper, Priest and Klein advanced a model in which there is a tendency for plaintiffs to prevail at trial with probability 50 percent. However, this note demonstrates that, in a simple, frequently employed model of litigation, it is possible for the cases that go to trial to result in plaintiff victory with any probability. Moreover, given any probability of plaintiff victory at trial, the probability of plaintiff victory among settled cases (had they been tried) may be any other probability. Further, data on the frequency of plaintiff victory does not clearly support the 50 percent tendency. In consequence, this note concludes that it does not seem appropriate to regard 50 percent plaintiff victories as a central tendency, either in theory or in fact.