Randomized clinical trial.

The randomized clinical trial has a minimum of four elements. These are: 1. The use of control patients who either receive no treatment, the conventional treatment, or a placebo. 2. The use of random assignment of treatment to be tested. 3. The avoidance of investigator bias by single or double masking procedures. 4. The development of a sound ethical basis for the conduct of the research. These elements are discussed and the principles illustrated by a brief discussion of the diabetic retinopathy study conducted by the National Eye Institute.

RCT Entities:   Population Interventions Outcomes