Implementation involves pre-specifying the timing and number of interim analyses, as well as the statistical boundaries for stopping the trial. The design can be complex and typically requires collaboration with a biostatistician.
1. Pre-Specification: Before the trial begins, researchers determine the number and timing of interim analyses. For example, they might decide to conduct an interim analysis after 25%, 50%, and 75% of the total sample size has been enrolled. 2. Statistical Boundaries: Researchers set statistical boundaries for efficacy and futility. If the interim results cross these boundaries, the trial may be stopped early. 3. Interim Analyses: At each interim point, the data is analyzed, and decisions are made based on the pre-specified criteria.
