Although stare decisis is a fundamental part of the legal model, up to now no one has examined it empirically in a comprehensive study. Doctrinal and philosophical studies abound, of course. But we found only four published empirical articles on this topic. Not only are some of the findings of these four studies open to question, but the authors of these studies failed to agree on their list of overruling and overruled cases. One of the four studies used the list collected by the Congressional Research Service, but this list is unreliable, mainly because its compilers failed to specify the criteria they employed to determine whether a given case ought to be placed on the list. We compiled our own list of cases covering a period of 46 terms – the Vinson, Warren, and Burger Courts, and the first 6 terms of the Rehnquist Court. We also listed the cases these overturning cases altered. For someone who has not conducted research on this topic, it might appear easy to identify the overruling and the overruled cases. This is not true. We had to formulate rules for the selection of cases and determine whether a given case conforms to the rules or not.

We first ascertained some of the characteristics of the overruling and overruled cases. We discovered that half the overruled decisions survived less than 21 years, while approximately 10 percent antedated 1900. Of the four Courts we inspected, the Warren Court overturned the most recent precedents and was most likely to overturn its own precedents. We also found that older precedents tended to be overturned by a much larger vote than newer precedents.