Comparative effectiveness research (CER) is the direct comparison of existing health care interventions to determine which work best for which patients and which pose the greatest benefits and harms. The core question of comparative effectiveness research is which treatment works best, for whom, and under what circumstances.[1] Engaging various stakeholders in this process, while difficult, makes research more applicable through providing information that improves patient decision making.[2]
The Institute of Medicine committee has defined CER as "the generation and synthesis of evidence that compares the benefits and harms of alternative methods to prevent, diagnose, treat, and monitor a clinical condition or to improve the delivery of care. The purpose of CER is to assist consumers, clinicians, purchasers, and policy makers to make informed decisions that will improve health care at both the individual and population levels."[3]
Comparative effectiveness research adopts many of the same approaches and methodologies as cost-effectiveness analysis, including the use of incremental cost-effectiveness ratios (ICERs) and quality-adjusted life years (QALYs). An important component of CER is the concept of pragmatic randomised controlled trials.[4] These clinical research trials measure the benefit produced by the treatment in routine clinical practice.