Methodological issues in using multiple years of the Medicare current beneficiary survey.

BACKGROUND: The analysis presented in this paper examines the multi-year capacity of the Medicare Current Beneficiary Survey (MCBS).
METHODS: We systematically reviewed the literature for methodological approaches in research using multiple years of the MCBS and categorized the studies by study design, use of survey sampling weights, and variance adjustments. We then replicated the approaches in an empirical demonstration using functional status (activities of daily living (ADL) and 2005-2007 MCBS data.
RESULTS: In the systematic review, we identified 22 pooled, 17 repeated cross-sectional, and 17 longitudinal studies. Less than half of these studies explicitly described the weighting approach or variance estimation. In the empirical demonstration, we showed that different study designs and weighting approaches will yield statistically different estimates.
CONCLUSION: There is a variety of methodological approaches when using multiple years of the MCBS, and some of them provide biased results. Research needs to improve in describing the methods and preferred approaches for using these complex data.