Measuring Circuit Splits: A Cautionary Note

Abstract

A number of researchers have recently published new measures of the Supreme Court’s behavior in resolving conflicts in the lower courts. These new measures represent an improvement over prior, cruder approaches, but it turns out that measuring the Court’s resolutions of conflicts is surprisingly difficult. The aim of this methodological comment is to describe those difficulties and to establish several conclusions that follow from them. First, the new measures of the Court’s behavior are certainly imprecise and may reflect biased samples. Second, using the Supreme Court Database, which some studies rely on to assemble a dataset of cases resolving conflicts, exacerbates the problems. Third, real precision may be infeasible given the nature of the enterprise.

Keywords: federal courts, Supreme Court, lower courts, circuit splits, certiorari, empirical legal studies, Supreme Court Database