Randomized Controlled Trial Involves at least one test/experimental treatment or inteverntion and one control treatment that can be a placebo treatment or no treatment
- Concurrent enrollment of subjects and follow-up of the experiemental test- and control-treated groups,
- Assignment of subjects to either the experimental treatment/intervention group or the control/placebo group through a random process, such as the use of a random-numbers table, and
- Follow-up of both groups to determine the outcome.

Double-Blind Randomized Controlled Trials Double-blind trials contain the rigor and methodology of a randomized controlled trial, but in addition are conducted so that neither the patient nor the investigator knows whether the patient is receiving the experimental treatment or the control treatment.
