Statsols Blog

What is the difference between Superiority vs. Equivalence vs. Non-inferiority in clinical trial design

The terms superiority, equivalence and non-inferiority are used frequently in publications on clinical trials. To someone starting out in clinical research these three terms and their precise meaning can be quite difficult to grasp. Indeed even experienced researchers have trouble getting their head around these hypotheses. So, what do these terms mean?

Topics: Introduction to Sample Size Clinical Trials nQuery

Why is Sample Size Important?

A good statistical study is one that is well designed and leads to valid conclusions. This however, is not always the case, even in published studies. In Cohen’s (1962) seminal power analysis of the journal of Abnormal and Social Psychology he concluded that over half of the published studies were insufficiently powered to result in statistical significance for the main hypothesis.

Topics: Introduction to Sample Size