Sample Size Expert Blog

A Brief Overview of Bayesian Analysis for Biostatisticians

Bayesian methods are becoming more common in clinical trials. Previously, a lack of computing in sample size software hindered the use of these methods, but improvements in the area have led to more widespread use. To examine what’s new and different about Bayesian sample size determination, we first need to consider what’s done in a traditional setting.

Topics: Introduction to Sample Size Reduce Sample Size Bayesian Assurance nQuery Bayes Dose Escalation Continual Reassessment Method (CRM)

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

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