This report models participation in the housing allowance program conducted as part of the Housing Assistance Supply Experiment, a research effort carried out from 1974 to 1979 in Brown County, Wisconsin, and St. Joseph County, Indiana. Specifically, it analyzes how an enrollee's failure on a required housing evaluation, and his response to that failure, affected his chances of actually participating in the program--that is, of ever receiving payments. Section II reports evaluation failure rates at enrollment and analyzes the factors affecting failure. Section III examines the aftermath of failing and the initial evaluation: how households responded and what influenced their decision. Section IV summarizes the outcome of the annual evaluation and the factors affecting a household's response to failure on it. Section V integrates the results to show how the various factors affected the chances both of an enrollee's ever receiving payments and of losing payments because his dwelling deteriorated. It concludes by discussing the policy implications of the findings.