Randomized controlled trials (RCTs) involve the comparison of at least two groups, which are usually an intervention and a placebo group, or two different interventions. The principal research question in most trials is to determine whether a new intervention is superior (more effective) to an existing intervention, control or placebo. This type of trial design is the superiority trial. Superiority trials are the most common type of comparative trial designs implemented in RCTs. Some trials however, may justify the use of equivalence and non-inferiority trials. These trial designs are more difficult and complex to