For helpful comments and suggestions, the author is grateful to George Alessandria, Susanto Basu, Yan Bai, Mark Bils, Yongsung Chang, Marcus Hagedorn, Baris Kaymak, Dirk Krueger, Kai Li, Ryan Michaels, Vincenzo Quadrini, Kjetil Storesletten, Zhaogang Song, Toni Whited, Liyan Yang, and many other seminar participants at Rochester, SED at Warsaw, AEA at San Francisco, University of Oslo, BI Norwegian Business School, the Nordic Summer Symposium in Macroeconomics in Denmark, and Peking University.