Solving the DMP Model Accurately
An accurate global algorithm is critical for quantifying the dynamics of the Diamond-Mortensen-Pissarides model. Loglinearization understates the mean and volatility of unemployment, overstates the unemployment-vacancy correlation, and ignores impulse responses that are an order of magnitude larger in recessions than in booms. Although improving on loglinearization, the second-order perturbation in logs also induces large errors. We demonstrate these insights in the context of Hagedorn and Manovskii (2008). Once solved accurately, their small surplus calibration fails to explain the Shimer (2005) puzzle. While the volatility of labor market tightness is close to the data, the unemployment volatility is too high.
We are grateful to Hang Bai, Andrew Chen, Daniele Coen-Pirani, Steven Davis, Paul Evans, Wouter Den Haan, Lars-Alexander Kuehn, Dale Mortensen, Paulina Restrepo-Echavarria, Etienne Wasmer, Randall Wright, and other seminar participants at The Ohio State University and the 2013 North American Summer Meeting of the Econometric Society for helpful comments. Nicolas Petrosky-Nadeau thanks Stanford Institute for Economic Policy Research at Stanford University for its hospitality. The Matlab programs for the accurate projection solution are available from the authors upon request. All remaining errors are our own. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.