Even with all of ASPEs efforts to increase comparability, there remain important differences across the ASPE-funded leaver studies that should be kept in mind when comparing them and drawing general conclusions from them. For example, the status of welfare leavers is likely affected by the welfare policies states have adopted, the economic opportunities prevailing in the states, and even the characteristics of welfare recipients themselves.
In addition, the leaver studies do not all focus on the same time period. Indeed, some studies focus on leavers from late 1998 while others examine leavers from late 1996/early 1997. The survey components of the leaver studies also cover different periods of time after leaving. For example, one leaver study interviews leavers over two years after exit from welfare while others conduct interviews six months after exit.
Further, although the survey instruments generally gather similar information, each was developed by a separate team of researchers. Each survey focuses on topics of interest in a particular state or locality, leading to differences in measured outcomes. In addition, the reliability of survey findings are affected by how well survey respondents represent the population of welfare leavers. Response rates to the surveys we include in this synthesis range from 51 to 76 percent (2). While not a guarantee of representative findings, higher response rates generally indicate more reliable results (3).
Finally, there are some small variations in how the studies define leavers and the types of leavers studied. For example, most but not all studies require a family to remain off welfare for two months to be considered a leaver (4). Further, some studies focus exclusively on single parent welfare leavers while others include information on two-parent and, in a few studies, child-only cases. A summary of the types of data used, the time periods analyzed, the study populations, and technical details of surveys appear in Appendix A.