Learning and Model Validation
This paper studies the following problem. An agent takes actions based on a possibly misspecified model. The agent is 'large', in the sense that his actions influence the model he is trying to learn about. The agent is aware of potential model misspecification and tries to detect it, in real-time, using an econometric specification test. If his model fails the test, he formulates a new better-fitting model. If his model passes the test, he uses it to formulate and implement a policy based on the provisional assumption that the current model is correctly specified, and will not change in the future. We claim that this testing and model validation process is an accurate description of most macroeconomic policy problems. Unfortunately, the dynamics produced by this process are not well understood. We make progress on this problem by relating it to a problem that is well understood. In particular, we relate it to the dynamics of constant-gain stochastic approximation algorithms. This enables us to appeal to well known results from the large deviations literature to help us understand the dynamics of testing and model revision. We show that as the agent applies an increasingly stringent specification test, the large deviation properties of the discrete model validation dynamics converge to those of the continuous learning dynamics. This sheds new light on the recent constant-gain learning literature.
|Date of creation:||03 Dec 2006|
|Date of revision:|
|Contact details of provider:|| Postal: Society for Economic Dynamics Marina Azzimonti Department of Economics Stonybrook University 10 Nicolls Road Stonybrook NY 11790 USA|
Web page: http://www.EconomicDynamics.org/
More information through EDIRC
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Vuong, Quang H, 1989. "Likelihood Ratio Tests for Model Selection and Non-nested Hypotheses," Econometrica, Econometric Society, vol. 57(2), pages 307-33, March.
- Thomas J. Sargent, 1975.
"The observational equivalence of natural and unnatural rate theories of macroeconomics,"
48, Federal Reserve Bank of Minneapolis.
- Sargent, Thomas J, 1976. "The Observational Equivalence of Natural and Unnatural Rate Theories of Macroeconomics," Journal of Political Economy, University of Chicago Press, vol. 84(3), pages 631-40, June.
- Banerjee, Abhijit & Bacchetta, Philippe & Aghion, Philippe, 2001.
"Currency Crises and Monetary Policy in an Economy with Credit Constraints,"
4554218, Harvard University Department of Economics.
- Aghion, Philippe & Bacchetta, Philippe & Banerjee, Abhijit, 2001. "Currency crises and monetary policy in an economy with credit constraints," European Economic Review, Elsevier, vol. 45(7), pages 1121-1150.
- Aghion, Philippe & Bacchetta, Philippe & Banerjee, Abhijit, 2000. "Currency Crises and Monetary Policy in an Economy with Credit Constraints," CEPR Discussion Papers 2529, C.E.P.R. Discussion Papers.
- Philippe Aghion & Philippe Bacchetta & Abhijit Banerjee, 2000. "Currency Crises and Monetary Policy in an Economy with Credit Constraints," Working Papers 00.07, Swiss National Bank, Study Center Gerzensee.
- William A. Brock & Cars H. Hommes, 1997.
"A Rational Route to Randomness,"
Econometric Society, vol. 65(5), pages 1059-1096, September.
- Timothy Cogley & Riccardo Colacito & Thomas J. Sargent, 2007.
"Benefits from U.S. Monetary Policy Experimentation in the Days of Samuelson and Solow and Lucas,"
Journal of Money, Credit and Banking,
Blackwell Publishing, vol. 39(s1), pages 67-99, 02.
- Timothy Cogley & Riccardo Colacito & Thomas J. Sargent, 2005. "Benefits from U.S. monetary policy experimentation in the days of Samuelson and Solow and Lucas," Proceedings, Board of Governors of the Federal Reserve System (U.S.).
- Brock,W.A. & Durlauf,S.N. & West,K.D., 2004.
"Model uncertainty and policy evaluation : some theory and empirics,"
19, Wisconsin Madison - Social Systems.
- William A. Brock & Steven N. Durlauf & Kenneth D. West, 2005. "Model uncertainty and policy evaluation: some theory and empirics," Proceedings, Federal Reserve Bank of San Francisco.
- Brock, William A. & Durlauf, Steven N. & West, Kenneth D., 2007. "Model uncertainty and policy evaluation: Some theory and empirics," Journal of Econometrics, Elsevier, vol. 136(2), pages 629-664, February.
- William A. Brock & Steven N. Durlauf & Kenneth D. West, 2004. "Model Uncertainty and Policy Evaluation: Some Theory and Empirics," NBER Working Papers 10916, National Bureau of Economic Research, Inc.
- Thomas J. Sargent & Noah Williams, 2003.
"Impacts of priors on convergence and escapes from Nash inflation,"
FRB Atlanta Working Paper
2003-14, Federal Reserve Bank of Atlanta.
- Thomas J. Sargent & Noah William, 2005. "Impacts of Priors on Convergence and Escapes from Nash Inflation," Review of Economic Dynamics, Elsevier for the Society for Economic Dynamics, vol. 8(2), pages 360-391, April.
- Yuichi Kitamura & Michael Stutzer, 1997. "An Information-Theoretic Alternative to Generalized Method of Moments Estimation," Econometrica, Econometric Society, vol. 65(4), pages 861-874, July.
- Timothy Cogley & Thomas Sargent & Riccardo Colacito, 2005. "Benefits from U.S. Monetary Policy Experimentation in the Days of Samuelson," 2005 Meeting Papers 791, Society for Economic Dynamics.
- Hansen, Lars Peter & Sargent, Thomas J., 1993. "Seasonality and approximation errors in rational expectations models," Journal of Econometrics, Elsevier, vol. 55(1-2), pages 21-55.
- Sargent, Thomas J., 1993. "Bounded Rationality in Macroeconomics: The Arne Ryde Memorial Lectures," OUP Catalogue, Oxford University Press, number 9780198288695, December.
- Evan W. Anderson & Lars Peter Hansen & Thomas J. Sargent, 2003. "A Quartet of Semigroups for Model Specification, Robustness, Prices of Risk, and Model Detection," Journal of the European Economic Association, MIT Press, vol. 1(1), pages 68-123, 03.
- Marcet, Albert & Sargent, Thomas J., 1989. "Convergence of least squares learning mechanisms in self-referential linear stochastic models," Journal of Economic Theory, Elsevier, vol. 48(2), pages 337-368, August.
When requesting a correction, please mention this item's handle: RePEc:red:sed006:178. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Christian Zimmermann)
If references are entirely missing, you can add them using this form.