First Author:   Harold Houba Vrije Universiteit and Tinbergen Institute hhouba@feweb.vu.nl   Department of Econometrics, De Boelelaan 1105 Amsterdam, 1081 HV, The Netherlands   +31 20 598 6014(Phone) +31 20 598 6014(Fax) http://www.feweb.vu.nl/medewerkers/hhouba/ Second Author: Quan Wen Vanderbilt University quan.wen@vanderbilt.edu   Department of Economics, VU Station B #351819, 2301 Vanderbilt Place Nashville, 37235-1819, USA   +1 615 322 0174(Phone) +1 615 3438495(Fax) http://sitemason.vanderbilt.edu/econ/wen