Effects of using specific versus general data in social program research

We present a comparison of results of similar analyses of a particular social program using two sources of data: one representative of the general population, and one representative of the population that actually is eligible for the social program. To do this, we focus on a particular public assistance program as implemented in Florida as our public policy program of choice. We compare the results of an analysis of the program's participation rates using US Census data for the general population of Florida to the results of the exact same model using a dataset that includes only the population of Florida that is actually eligible for the program. We find that while generally signs of effects remain the same, they do not always remain the same; moreover, significance differs, and the marginal effects of various demographic and socio-economic factors on program participation rates vary greatly. We submit that such differences are important for policymakers to recognize so that they can effectively target programs to those individuals and geographic areas most in need of such programs.