Document Type


Publication Date


Journal Title

Case Western Reserve Law Review




Through the use of statistical and econometric techniques, social scientists can offer powerful new insights into the causes and effects of changes in the law. Despite a long tradition of empirical research by both economists and political scientists into diverse political institutions, investigations of the common law using methods more sophisticated than simply counting cases or votes is a relatively recent development. Given the natural laboratory provided by the heterogenous development of the common law in the multitude of jurisdictions in the United States, the lack of such research is surprising. Extending this scholarly tradition to common law subjects promises great rewards. Changes in the common law have significant effects on virtually every aspect of modern life. Just in the last fifty years, for example, there have been far-reaching developments in employment law, landlord-tenant law, and tort law. Evaluations of the effects of these changes would provide valuable information to legislatures and courts considering such changes. Even greater benefits are possible for the development of the economic analysis of law, where empirical work on the common law has lagged far behind theoretical work.

The difficulty of accurately dating changes in the common law partly explains the absence of research into their causes and consequences. Unlike statutes, common law changes are often unannounced or hidden beneath layers of obscure language. Although courts sometimes do make an explicit innovation, in many instances courts characterize the change simply as the application of existing precedent to slightly different factual circumstances. The many sources of the common law introduce further complications. Not only may a decision come from different levels of a state's courts, but federal courts may decide questions of state law prior to the state courts in some circumstances. Finally, the development of the common law is an iterative process. Courts may change their interpretation of existing precedent or explicitly overrule it. What appears to be one rule may turn out years later to be an entirely different rule.

Social science research on common law issues has suffered from three difficulties:

* inconsistent treatment of opinions;

* incomplete analysis of changes in the law; and

* hidden choices which affect results.

In this Article, I attempt to delineate and resolve various methodological problems that can critically affect research conclusions in this area.

In Part II, I develop eighteen general principles to guide researchers in solving the problem of dating changes. Although there are no simple answers which resolve every problem, researchers' application of these principles will ensure that their decisions about dating changes are appropriate to the problem studied and, just as important, are open to scholarly review.

In Part III, I present my own analysis of the impact of the modern law of wrongful discharge and reanalyze two recent empirical papers by economists which analyzed the impact of the modem common law development of wrongful discharge claims in the United States. This Part not only provides a clear example of the application of the general principles but demonstrates how different choices can affect the results of empirical research.

The results are both reassuring and a cause for concern. They are reassuring because they suggest that conclusions are not "too" sensitive to debatable methodological choices. Point estimates change, often substantially, but wholesale reversals of conclusions do not occur. The concern stems from the sensitivity of empirical results to the dating method used. Unless researchers use systematic judgments informed by legal reasoning in addition to empirical skill, they are in danger of making critical errors. Although caution is advisable in generalizing from the limited number of empirical examples which space permits here, the results of the case studies are encouraging. They suggest that such studies are reliable if done properly. More importantly, the principles developed here provide researchers with a clear framework for approaching these important choices.

First Page


Volume Number



Case Western Reserve University School of Law

Included in

Law Commons



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.