Superiority Analysis

A clinical trial addresses a hypothesis.  If the hypothesis is that Drug A is better than Drug B/placebo, then it is appropriate to set up the trial design and statistical plan to detect superiority.  Supriority trials are always used when a comparison is made to a placebo.  The effect in the treatment group must be clearly superior to any effect of the placebo. Superiority trials are also helpful in making marketing statements – ‘our drug is better than your drug’.