ABSTRACT
SCARCITY OF QUANTITATIVE scholarship has been a serious shortcoming of legal research, including economic analysis of law. When hypotheses cannot be tested by means of experiments, whether contrived or natural, and the results assessed rigorously by reference to the conventions of statistical inference, speculation is rampant and knowledge meager. The situation can be improved, I shall argue, by making greater use of citations analysis, guided by economic theory, as a methodology of quantitative empirical research. Both adjudication, a central practical activity of the legal system, and legal research are citation-heavy activities. Judges, lawyers who brief and argue cases, and law professors and students engaged in traditional legal-doctrinal research could all be thought, with only slight exaggeration, to make their living in part by careful citation both of judicial decisions and of law-review articles and other secondary materials. The seriousness with which the legal profession takes citations suggests that the analysis of citations in law is likely to uncover more systematic features, a more consistent practice, of citing than would a similar analysis in fields for which citing is of less consequence. Counting citations is already a well-established method of empirical research in law, economics, sociology (especially the sociology of science), and academic administration. It is being used increasingly in law 1 —mainly in economic analysis of law—yet it remains limited in relation to potential topics. Statistical analysis of citations practices has become fast and cheap as a result of faster, more powerful computers, and of computerized citations indexes. 2 The cost of citations analysis thus is falling. But the fact that a particular kind of research is feasible, even easy to do, cannot explain why anyone wants to do it. Low cost is not enough; there have to be benefits—and anyway the opportunity costs of adopting one research method over another are not low. Citations analysis is growing mainly because it enables rigorous quantitative analysis of elusive but important social phenomena such as reputation, influence, prestige, celebrity, the diffusion of knowledge, the rise and decline of schools of thought, stare decisis (that is, the basing of judicial decision on previous decisions—precedents), the quality of scholarly output, the quality of journals, and the productivity of scholars, judges, courts, and law schools. 3
