Sample design and cohort selection in the Hispanic Community Health Study/Study of Latinos

Abstract

Purpose: The Hispanic Community Health Study (HCHS)/Study of Latinos (SOL) is a multicenter, community-based cohort study of Hispanic/Latino adults in the United States. A diverse participant sample is required that is both representative of the target population and likely to remain engaged throughout follow-up. The choice of sample design, its rationale, and benefits and challenges of design decisions are described in this study.

Methods: The study design calls for recruitment and follow-up of a cohort of 16,000 Hispanics/Latinos 18-74 years of age, with 62.5% (10,000) over 44 years of age and adequate subgroup sample sizes to support inference by Hispanic/Latino background. Participants are recruited in community areas surrounding four field centers in the Bronx, Chicago, Miami, and San Diego. A two-stage area probability sample of households is selected with stratification and oversampling incorporated at each stage to provide a broadly diverse sample, offer efficiencies in field operations, and ensure that the target age distribution is obtained.

Conclusions: Embedding probability sampling within this traditional, multisite cohort study design enables competing research objectives to be met. However, the use of probability sampling requires developing solutions to some unique challenges in both sample selection and recruitment, as described here.

Figure 1

Results of a Simulated Comparison of Probability and Non-Probability Samples Using Data from the 2005 Medical Expenditure Panel Survey (MEPS) Legend. ‘Population’ corresponds to estimates based on the MEPS sample and therefore representing the 2005 US resident, non-institutionalized population. ‘Clinic Users (Raw)’ corresponds to estimates based on the subset of the MEPS sample reporting one or more physician visits in the past year. ‘Clinic Users (Standardized)’ corresponds to estimates based on the MEPS clinic-users sample, standardized to the 2005 US resident, non-institutionalized population distributions for age, race/ethnicity, and gender.

Figure 1

Results of a Simulated Comparison of Probability and Non-Probability Samples Using Data from the 2005 Medical Expenditure Panel Survey (MEPS) Legend. ‘Population’ corresponds to estimates based on the MEPS sample and therefore representing the 2005 US resident, non-institutionalized population. ‘Clinic Users (Raw)’ corresponds to estimates based on the subset of the MEPS sample reporting one or more physician visits in the past year. ‘Clinic Users (Standardized)’ corresponds to estimates based on the MEPS clinic-users sample, standardized to the 2005 US resident, non-institutionalized population distributions for age, race/ethnicity, and gender.