National probability samples in studies of low-prevalence diseases. Part II: Designing and implementing the HIV cost and services utilization study sample
Frankel, M. R., Shapiro, M. F., Duan, N., Morton, S., Berry, S. H., Brown, J. A., ... Bozzette, S. A. (1999). National probability samples in studies of low-prevalence diseases. Part II: Designing and implementing the HIV cost and services utilization study sample. Health Services Research, 34(5), 969-992.
Objective. The design and implementation of a nationally representative probability sample of persons with a low-prevalence disease, HIV/AIDS. Data Sources/Study Setting. One of the most significant roadblocks to the generalizability of primary data collected about persons with a low-prevalence disease is the lack of a complete methodology for efficiently generating and enrolling probability samples. The methodology developed by the HCSUS consortium uses a flexible, provider-based approach to multistage sampling that minimizes the quantity of data necessary for implementation. Study Design. To produce a valid national probability sample, we combined a provider-based multistage design with the M.D.-colleague recruitment model often used in non-probability site-specific studies. Data Collection. Across the contiguous United States, reported AIDS cases for metropolitan areas and rural counties. In selected areas, caseloads for known providers for HIV patients and a random sample of other providers. For selected providers, anonymous patient visit records. Principal Findings. It was possible to obtain all data necessary to implement a multistage design for sampling individual HIV-infected persons under medical care with known probabilities. Taking account of both patient and provider nonresponse, we succeeded in obtaining in-person or proxy interviews from subjects representing over 70 percent of the eligible target population. Conclusions. It is possible to design and implement a national probability sample of persons with a low-prevalence disease, even if it is stigmatized