The Survey of Program Dynamics (SPD) is a ten-year longitudinal survey designed to provide data about families before and after the 1996 nationwide welfare reform. The SPD's value derives from three characteristics: (1) it was designed to focus its content on welfare; (2) its sample is representative of the 1992 and 1993 civilian noninstitutionalized population; and (3) its response rates are reasonably comparable to other longitudinal household surveys. Attrition of respondents is nevertheless a problem that has necessitated the use of incentives and special efforts to return nonrespondents to the survey.

Because researchers have questioned the usefulness of data from the SPD due to the attrition of respondents, the purpose of this paper is to evaluate the quality of the SPD data. The conclusions drawn from the analysis below is that the SPD data are representative of the population when compared with the Current Population Survey (CPS), and the SPD response rates are comparable with response rates from two other major longitudinal household surveys -- the Panel Study of Income Dynamics (PSID) and the National Longitudinal Survey of Youth (NLS-Y). However, attrition is still a problem for the SPD. Based on an experimental study that the Census Bureau conducted in 1998, monetary incentives were successful in gaining cooperation from panel nonrespondents, which suggests that SPD adopt the use of monetary incentives to reduce attrition.

This paper addresses the following questions:

• What role does SPD play in measuring the effects of welfare reform?

• How do the SPD's response rates compare with those of the 1968 PSID and 1979 NLS-Y?

• What affected SPD attrition?

• How do data from the SPD compare with data from the CPS March Demographic Supplement?

• What was learned from the SPD Exploratory Attrition Study ⁽²⁾ and the use of incentives?

• What response rates are expected if the Census Bureau receives funding to bring back in nonrespondents to the 1997 SPD and the 1992 and 1993 Survey and Income Participation Program (SIPP)?