ABSTRACT
This chapter provides a high-level overview of the most common types of epidemiological studies relevant to data analysis from the EHR. These observational study designs include including cross-sectional studies, cohort studies with and without repeating measures, and case–control studies. Particularly attention is given to retrospective cohort studies and matched case–control studies, as these are widely used approaches for secondary data analysis from the EHR. In fact, the EHR itself can be conceived of as an open cohort, which affords flexibility in the sampling and analytic approaches used. The goal of this chapter is to move from the research database to an analytic dataset, and numerous examples demonstrate the selection process for each of the study types. Lastly, the chapter covers sample size and power calculations for both prospective and retrospective research.
