Kinds of clinical trials Review article

Abstract

Observational, cohort, cross-sectional and randomized studies are the most common types of clinical trial used in practice. In observational study influence of a treatment is not driven by protocol. Randomization which uses random allocation of different interventions to subjects is an effective method for balancing confounding factors. Double-blind study is an experimental procedure in which neither the subjects of the experiment (patient) nor the persons administering the experiment (physician) know the critical aspects of the experiment.