Duane F. Alwin is Tracy Winfree and Ted H. McCourtney Professor in Sociology, Demography, and Human Development at Pennsylvania State University, where he is affiliated with the Population Research Institute, the Survey Research Center, and the Gerontology Center. Prior to moving to Penn State, Alwin held an appointment for 23 years in the Survey Research Center of the Institute for Social Research, University of Michigan. The focus of his research and teaching includes survey methodology, families and children, socio-economic inequalities and health disparities, aging and the life course, and...