The Advisory Committee on Civil Rules has been considering a proposal to revise Fed. R. Civil P. 23 to create new certification standards that would apply only to settlement class actions. The Committee sought empirical research from the Center to help it decide how to proceed. The Center conducted the research in two phases during 2002-2004. This report is the first phase. For the second phase see Attorney Reports on the Impact of Amchem and Ortiz on Choice of a Federal or State Forum in Class Action Litigation: A Report to the Advisory Committee on Civil Rules Regarding a Case-based Survey of Attorneys (2004).

The Class Action Subcommittee of the Advisory Committee on Civil Rules asked the Federal Judicial Center to examine the impact, if any, of the Supreme Court decisions in Amchem and Ortiz on the rate at which plaintiffs file class actions in federal courts. The resulting report describes trends in federal class action filings, removals, settlements, and dismissals during the period from January 1994 through June 2001 and identifies certain discernible changes after the two decisions. The report discusses the results of a time-series analysis that tested whether there were any statistically significant relationships between the two decisions and the filing/disposition patterns found. Certain of the changes observed were not likely to have occurred by chance; however, many factors might have affected filings.