As is clear from the long list of authors, a fairly large number of individuals contributed to this report. The authors wish to acknowledge and thank Dan Buckley, Joan Mattei, and Nancy Holden for conducting the computer programming necessary to generate the many tables in this report, and Annette Protonentis for expert word processing, table formatting advice, and extraordinary patience in the production of the finished document. Peter Kemper provided extremely valuable advice throughout and comments on early drafts of this paper. Judith Wooldridge conducted some of the sensitivity tests that are reported in detail elsewhere but are summarized here. Finally, the internal and external reviewers selected by the Department of Health and Human Services provided useful comments on an early draft of this report. To all contributors, thank you for your assistance.