projects center on optimal resource allocation, choice modeling, and complex latent structures. He has a Ph.D. in mathematical statistics from Harvard University.

J. MICHAEL BRICK is senior statistician, vice president, and associate director of the statistical staff at Westat. He has 25 years of experience and expertise in sample design and estimation for large surveys, the theory and practice of telephone surveys, the techniques of total quality management and survey quality control, nonresponse and bias evaluation, and survey methodology. He has contributed to the statistical and substantive aspects of numerous studies and to statistical methodology research in several areas, including education, transportation, and product injury studies. He is a fellow of the American Statistical Association, an elected member of the International Statistical Institute, and a research professor in the Joint Program in Survey Methodology at the University of Maryland. He has a B.S. in mathematics from the University of Dayton and M.A. and Ph.D. degrees in statistics from American University.

EDWARD A. FRONGILLO, JR., is associate professor in the Division of Nutritional Sciences and director of the Office of Statistical Consulting at Cornell University. He previously served as the director of the Program in International Nutrition at Cornell. His current research activities include the Multicentre Growth Reference Study of the World Health Organization; the conceptualization, measurement, and consequences of food insecurity in elders and families in poor countries and in North America; and the role of food assistance programs in alleviating consequences of food insecurity. He is a member of the editorial boards of the Journal of Nutrition and the Journal of Gerontology: Medical Sciences. He has an M.S. in biometry, an M.S. in human nutrition, and a Ph.D. in biometry, all from Cornell University.

PAUL W. HOLLAND holds the Frederic M. Lord chair in measurement and statistics at the Educational Testing Service (ETS). His association with ETS began in 1975 as director of the Research Statistics Group, and in 1986 he was appointed its first distinguished research scientist. He left ETS in 1993 to join the faculty at University of California, Berkeley, as a professor in the Graduate School of Education and Department of Statistics but returned in 2000 to his current position at ETS. His research interests include psychometrics, causal inference of educational interventions in nonexperimental studies, discrete multivariate data analysis, and the analysis of social networks. He was designated a national associate of the National Research Council in 2002. He has an M.A. and a Ph.D. in statistics