This report was prepared for the National Center for Research in Vocational Education, University of California at Berkeley, with support from the Office of Vocational and Adult Education, U.S. Department of Education. It fulfills the National Center's obligation under section 404(b)(2) of the 1990 Amendments to the Carl D. Perkins Vocational and Applied Technology Education Act. Thanks are due to former colleagues in the Directorate for Education, Employment, Labor, and Social Affairs at the OECD, who generously shared information and ideas. Jeff King and Margaret Vickers also gave much detailed criticism, useful information, and extraordinarily helpful advice in response to two earlier drafts. Some of their suggestions have been incorporated directly into the text, and others have been included as footnotes. In spite of all this help, the authors bear responsibility for any remaining errors of fact or interpretation, and the opinions expressed here do not necessarily represent those of the funding agency, colleagues, or reviewers.