Often, DHHS recommends that applicants be sampled using the same sampling intervals used in selecting recipient cases, to avoid the need to calculate weights. If the same sampling rate is used for both groups, active cases in the sample at each point in time are representative of all active cases, without weighting. A major motivation for this approach has been to allow states to meet the federal cost neutrality requirements more easily. For cost neutrality, the active cases in the research sample should be representative of the full active caseload in the research counties at each point in time, so that the impact of the program on AFDC program costs can be assessed.(17) (Although cost neutrality is not the subject of this report, it is important to note here how these requirements shape the sample designs that are also used for impact analyses.) If applicants are sampled at a different rate than recipients, it is still possible to achieve representativeness for cost neutrality purposes by appropriate weighting. As long as the sampling rate for applicants remains the same over time, construction of such weights is straightforward.(18) Whether or not weights are used, as soon as sampling of applicants ceases, the sample is no longer representative of the full active caseload. The active cases that remain in the sample increasingly will underrepresent newer cases.
In the impact analysis, the applicant and recipient samples are each of interest in their own right; in most cases, impact studies analyze data on the two groups separately. Applicant cases experience the new program from the beginning of their spell, and thus are more indicative of long-term effects; they also are representative of the full range of cases that apply for AFDC. Recipient cases give evidence of the short-term effects of welfare reform on the existing caseload.
Because the recipient group represents the stock of cases at a point in time, it is made up of long- term recipients to a much larger extent than the flow of applicant cases. The recipient sample may thus indicate the effects of reform on the most disadvantaged portion of the caseload, particularly if analysis is restricted to long-term recipients.