Diker-Tishman Professor of Sociology, was born in Topeka, Kansas and grew up in New Britain, Connecticut. He did his undergraduate work in sociology and mathematics at Dartmouth College and his graduate work in this department, receiving his degree in 1977. After leaving Harvard he did a one year post-doctoral fellowship at the Institute for Research on Poverty at the University of Wisconsin and a two-year fellowship at the National Opinion Research Center (NORC) at the University of Chicago. In 1980 he joined the Sociology Department at Northwestern University. During his twelve years at Northwestern he was Director of the Program in Mathematical Methods in the Social Sciences and for four years chair of the Department of Sociology. He was a founding member of Northwestern's Department of Statistics, and held a courtesy appointment in Economics. From 1984 to 1986 he was Director of the Economics Research Center at NORC. He has been a member of the Harvard department since 1992, and, since 2002, at the Harvard Kennedy School of Government (HKS). He is currently doing research on several topics: The Ten Point Coalition, a group of black ministers who are working with the Boston police to reduce youth violence; statistical models for causal analysis; the effects of education on mental ability; causes of the racial difference in performance in elite colleges and universities; changes in the racial differential in imprisonment rates over the past sixty years.