Which item specifies the timing of any planned interim analysis?

• A. The data management plan
• B. The randomization procedures
• C. The patient recruitment strategy
• D. The timing of any planned interim analysis

Answer: (D)

Interim analyses are potential early looks at accumulating data, and their timing must be defined before the trial starts. Pre-specifying when these analyses occur (and the stopping rules that will be used) protects trial integrity by avoiding bias from data peeking and helps control statistical error rates. The element that directly addresses this is the timing of any planned interim analysis, which is typically described in the protocol and the statistical analysis plan (often with oversight by an independent data monitoring committee). Other items focus on data handling, how participants are randomized, or how recruitment is conducted, and do not specify when interim analyses will happen.