Trends in the Covariance Structure of Earnings in the U.S.: 1969-1987 Robert A. Moffitt Johns Hopkins University Peter Gottschalk Boston College June 1993 Revised, July 1995 This project was supported by grants from the U.S. Department of Health and Human Services through the Institute for Research on Poverty and from the U.S. Department of Labor through the National Bureau of Economic Research. The authors would like to thank Richard Blundell, Charles Brown, James Heckman, Costas Meghir, Gary Solon, and the members of seminars and workshops at several universities for comments on this version of the paper, as well as Thomas MaCurdy for comments on an earlier version. For assistance on the project, the authors would like to thank Amit Dar, Philip Merrigan, Reema Nayar, Renya Reed, Robert Reville, and Thomas Vanderveen at Brown University and Alpay Filizteken at Boston College. 01/01/04