Comparative effectiveness research - what is it and how does one do it?

Recent initiatives have increased focus on medical research that explores robust comparisons of clinical approaches broadly defined as comparative effectiveness research (CER). Federal mandates have generated definitions, established priorities, and offered organizational approaches for coordinating and conducting CER. This review will summarize the various definitions of CER, the role of cost assessment, and key study components of CER including study populations, study design, the use of secondary data, comparators employed in studies, outcome measures, and how results of CER should be disseminated.