title: Randomized clinical trial.
abstract: 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.
mesh_terms: D002986:Clinical Trials as Topic / Q000592:standards*; D003930:Diabetic Retinopathy / Q000601:surgery*; D004311:Double-Blind Method; D004992:Ethics, Medical; D005500:Follow-Up Studies; D006801:Humans; D053685:Laser Therapy; D007834:Lasers; D011897:Random Allocation; D012107:Research Design