Interventional Study Designs.

Interventional studies are specifically designed to evaluate direct impact of therapeutic or preventive measures on outcomes by assigning participants into treatment/intervention or control group. Main types of interventional study designs are: Single-arm interventional studies, non-randomized controlled trials, cross-over trials, randomized controlled trials, and cluster randomized trials. Each of these study designs has its own set of advantages and disadvantages, which need to be assessed and reviewed in the design phase of the study to choose the most apt design. Purpose of this article is to provide concept and processes of various interventional study designs along with their utility and limitations.