First, the benefits, harms, and costs of a test or treatment are considered. Benefits include improvements in health or quality of life. Harms include adverse effects, unnecessary care, or care that ultimately hurts the patient. Second, costs include the cost of the test or treatment itself plus costs from any unwanted events caused by the test or treatment. Third, cost-effectiveness analysis evaluates the value of different tests or treatments by comparing the benefits, harms, and costs of one type of health care with others. Comparative effectiveness research is research that can help patients, providers, and policymakers compare the benefits and harms of different types of care.