The standard way to assess medical technologies is to conduct a randomized clinical trial. Patients are randomly assigned to groups receiving alternative treatments, and outcomes are monitored over a long period of time. For example, some victims of left main coronary artery disease may undergo coronary artery bypass surgery, and others may receive medical treatment with nitroglycerine and beta blockers. Comparison of five-year mortality and morbidity in the two groups helps to determine the relative appropriateness of the two procedures. In addition, information about quality of life and cost can also be collected and compared.