Approaches to Evaluating Welfare Reform: Lessons from Five State Demonstrations. B. ESTIMATING ENTRY EFFECTS


Even in an experimental evaluation in which random assignment is implemented properly, the validity of impact estimates might be questioned if the adoption of welfare reform has induced substantial entry effects. Entry effects arise when the adoption of a welfare reform package either encourages or discourages applications for welfare, thereby changing the composition of the population of welfare applicants. For example, a welfare reform initiative that expands job- training programs might encourage applications for welfare, while a welfare reform initiative with stringent time limits might discourage applications. Entry effects do not bias impact estimates for the population that applies for assistance following the implementation of welfare reform. Nonetheless, when entry effects are present, impact estimates may not be valid for the population that would have applied for assistance in the absence of welfare reform. The terms and conditions of current Section 1115 welfare waivers state, "The evaluation contractor will explain how entry effects can be determined and will describe the methodology which will be employed to determine the entry effects of " the welfare reform program.