Where is the timing of any planned interim analysis described?

• A. The adverse event reporting procedures
• B. The description of the statistical methods, including timing of planned interim analysis
• C. The data management plan
• D. The patient consent process

Answer: (B)

Interim analysis timing is a statistical design detail. It belongs in the description of the statistical methods (often in the protocol’s statistical analysis plan) because it defines when the data will be looked at early and how that affects the study’s conclusions. The plan should specify how many interim looks will occur, the exact timing criteria (for example, after a certain number of events or participants, or at predefined time points), and any stopping rules or boundaries used to decide whether to continue, modify, or stop the trial. Documenting this up front helps control Type I error, preserve study integrity, and ensure consistent decision-making.

Other sections focus on different aspects: adverse event reporting describes safety monitoring procedures; the data management plan covers data collection, cleaning, and handling; and the patient consent process relates to participants’ authorization and rights. These areas do not define when interim analyses will occur.