Comparative Effectiveness Research is defined in the PPACA as "research evaluation and comparing health outcomes and clinical effectiveness, risks, and benefits of two or more medical treatments, services, and items." Treatment, services, and items were defined as "healthcare interventions; protocols for treatment, care management, and delivery; procedures; medical devices; diagnostic tools; pharmaceuticals; integrative health practices; any other strategies or items being used in the treatment, management, and diagnosis, or prevention of, illness or injury in individuals."
The PPACA further set forth that the PCORI should focus on Comparative Effectiveness Research in existing clusters or subgroups of the population that are underserved or unrepresented in the current clinical literature. These clusters or subgroups tend to relate to ethnicity, gender, age, and comorbidities. These are called sensitivity analysis in that the analysis focuses strictly on these subgroups within a population.
The research designs associated with Comparative Effectiveness Research under the guise of the PPACA include randomized trials and observational designs such as prospective cohort and retrospective cohort. Randomized trials are more feasible than randomized controlled trials because the randomization occurs at the intervention level rather than the patient level. PCORI further stipulated that observational designs should meet certain benchmark criteria before valid generalizations can be made: Valid research questions, explicitly defined inclusion and exclusion criteria for participation, comparable interventions or treatments, sound secondary data sources, and transparency of treatment and analysis protocols.
Federal legislation has approved the use of observational research designs like the retrospective cohort design where data and outcomes already exist, making research much more feasible and user-friendly to conduct.