Comparative effectiveness research (CER) is defined as “the conduct and synthesis of research comparing the benefits and harms of different interventions and strategies to prevent, diagnose, treat and monitor health conditions in “’real-world’ settings.” The goal of CER is to improve patient outcomes by providing decision-makers, such as patients, providers, policy-makers, and payers, with information as to which interventions are most effective for specific types of patients.

This briefing provides descriptions of both experimental and nonexperimental study designs and methods that may be used to address CER study questions.