a co-editor, three anonymous referees, as well as participants at the Washington University in St. Louis, the Summer Meeting of the Econometric Society, and the Society for Advanced Economic Theory Conference, for their insightful comments and suggestions. Financial support from Academia Sinica, the Ministry of Science and Technology, and the Weidenbaum Center on the Economy, Government, and Public Policy is gratefully acknowledged. The usual disclaimer applies. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.