In section 302 of the Judicial Improvements Act of 1990, Congress took steps to address long-felt concerns about the capacity of the federal judicial system to provide, within a reasonable time, a uniform construction of federal law where uniformity is needed. Adopting a recommendation of the Federal Courts Study Committee, Congress asked that the Federal Judicial Center undertake a study to determine "the number and frequency of conflicts among the judicial circuits . . . that remain unresolved because they are not heard by the Supreme Court." The Center asked the author to design and conduct the study. The results of the first phase of the research are presented in this report.