Practical guide to understanding Comparative Effectiveness Research (CER).

"Comparative effectiveness research" (CER) is not a new concept; however, recently it has been popularized as a method to develop scientifically sound actionable data by which patients, physicians, payers, and policymakers may make informed health care decisions. Fundamental to CER is that the comparative data are derived from large diverse populations of patients assembled from point-of-care general primary care practices and that measured outcomes include patient value judgments. The challenge is to obtain scientifically valid data to be acted upon by decision-making stakeholders with potentially quite diversely different agenda. The process requires very thoughtful research designs modulated by complex statistical and analytic methods. This article is composed of a guiding narrative with an extensive set of tables outlining many of the details required in performing and understanding CER. It ends with short discussions of three example papers, limitations of the method, and how a practicing physician may view such reports.