As a result of health care reform, medicine has entered a new era of comparative effectiveness. The Patient Protection and Affordable Care Act created the nation’s first comprehensive comparative effectiveness research program, investing in CER at record levels and establishing a new regulatory framework for oversight of the research. CER attracts considerable enthusiasm as a tool for reform because it compares competing interventions to determine which works best, supplying critical information for medical decision-making and health policy. In theory, better evidence (...) of how treatments fare relative to one another will translate to better medical care. According to some optimistic accounts, CER can lead to a “revolution” in clinical practice, has transformative power “to reshape major portions of the practice of medicine,” and represents a major “turning point” for the health care system. (shrink)