Committee on National Statistics, National Research Council ; Moffitt, Robert ; National Research Council, Panel on Data and Methods for Measuring the Effects of Changes in Social Welfare Programs Staff ; Panel on Data and Methods for Measuring the Effects of Changes in Social Welfare Programs, Robert A. Moffitt and Michele Ver Ploeg ; Ver Ploeg, Michele ; Commission on Behavioral and Social Sciences and Education ; Committee on National Statistics ; Division of Behavioral and Social Sciences and Education ; Moffitt, Robert A. ; Panel on Data and Methods for Measuring the Effects of Changes in Social Welfare Programs ; Ploeg, Michele Ver ; National Research Council (U.S.)