6 Sample Size Calculations for Clustered and Longitudinal Outcomes
potentially harmful trial and leads to a waste of resources without producing
useful results. The sample size estimate will allow the estimation of total cost
of the proposed study. While the exact final number that will be used for anal-
ysis will be unknown due to missing information such as lack of demographic
information and clinical information, it is still desirable to determine a target
sample size based on the proposed study design. In this section, we describe
the general information needed to estimate the sample size for the trial.
1. Choose the primary endpoint
The primary endpoint should be chosen so that the primary objective of the
trial can be assessed, and the primary ...