Design of a clinical trial that includes a balanced and randomized group of test subjects in terms of age and gender (where applicable), a control group following the same test protocol without actually receiving drug (placebo), and an independent review of the trial data. Trials may be open, blind or double-blind.
A prospective clinical trial comparing two or more treatments, or placebo and treatment(s) in similar groups of patients or within patients. A controlled trial may or may not use randomization to assign patients to groups, and it may or may not use blinding to prevent them from knowing which treatment they get.
Trials in which one group gets an experimental treatment and another gets either a placebo or an approved therapy. Participants do not usually know which group they are in.