Clinical trial as the name suggests is a kind of a study, which involves research, which mainly involves the effectiveness of drugs and determines the level of safety that a drug provides. Clinical trial involves volunteers, so that the drugs can be tested on them, these volunteers are referred to as subjects for the study.

Every trial should have a design before it takes place. Design for the manner in which the clinical trial has to be performed. As there are many subjects or volunteers involved in each clinical trial, the design focuses on their usage in the research.

Different kind of organizations or individuals namely physicians, pharmaceutical companies institutions etc sponsor these clinical trials. Sponsors also play an important role in choosing the design of the design of the trials.

While designing, a sponsor decides the number of patients who are going to participate in the trial. In a clinical trial if the number of patients involved i.e. if the sample size is large, more statistics are present for the better outcome of the trial, as a wide range of subjects are involved in the trial.

Types of Clinical Trial Designs

This kind of clinical trial involves the treatment of volunteers, which have been kept on a treatment, which is experimental and is tried on them for the first time. The drugs, which are getting tested, may not be having a license to be tested on human beings or as a treatment for a specific condition.

In this kind of a clinical trial a control group is compared to an experimental group in a test of a causal hypothesis. For example, if 'C' causes 'E', when we introduce 'C' into the experimental group but not into the control group, we should find 'E' occurring in the experimental group at a significantly greater rate than in the control group.