This paper uses meta-analytic techniques to provide a systematic appraisal of how welfare reform policies in six studies representing 14 welfare programs have affected marriage and cohabitation among single-parent families overall and for a variety of subpopulations. In each of the studies examined, single parents were randomly assigned to a program that included some combination of mandatory employment services, enhanced earnings disregards, time limits on welfare receipt, or equalized eligibility for two-parent families, or to a control group that was neither eligible for the program’s services nor subject to its requirements. Random assignment ensures that any differences in outcomes for these two groups over time are attributable to the programs that were studied.