The Class Action Fairness Act of 2005 (CAFA) (Pub. L. No. 109-2, 119 Stat. 4 (2005)) expanded the federal courts' diversity of citizenship jurisdiction over class action litigation. Congress's intent was, in part, to shift some class action litigation from the state courts to the federal courts. Passage of the Act sparked concerns about the impact of these additional class actions on the federal courts' rocedures and workload. In light of these concerns, the Judicial Conference's Advisory Committee on Civil Rules (Advisory Committee)1 asked the Federal Judicial Center (FJC) to study the impact of CAFA on the federal courts. This report marks the end of the first phase of the FJC study on the impact of CAFA on the number of class actions initiated in the federal courts. This report presents interim findings on class actions filings and removals in the federal courts from July 1, 2001, through June 30, 2007. These findings are consistent with the hypothesis that CAFA has caused an increased number of class actions based on diversity of citizenship jurisdiction to be filed in the federal courts.