The major contributions of twentieth century econometrics to knowledge were the definition of causal parameters within well-defined economic models in which agents are constrained by resources and markets and causes are interrelated, the analysis of what is required to recover causal parameters from data (the identification problem), and clarification of the role of causal parameters in policy evaluation and in forecasting the effects of policies never previously experienced. This paper summarizes the development ofthese ideas by the Cowles Commission, the response to their work by structural econometricians and VAR econometricians, and the response to structural and VAR econometrics by calibrators, advocates of natural and social experiments, and by nonparametric econometricians and statisticians.

Understanding Black-White Wage Differentials, 1960-1990 Author(s): James J. Heckman, Thomas M. Lyons, Petra E. Todd Source: The American Economic Review, Vol. 90, No. 2, Papers and Proceedings of the One Hundred Twelfth Annual Meeting of the American Economic Association, (May, 2000), pp. 344 -349 Published by: American Economic Association Stable URL: http://www.jstor.org/stable/117248 Accessed: 16/08/2008 00:56