Which analysis approach includes all participants in the groups to which they were randomized, regardless of whether they completed the intervention?

Which analysis approach includes all participants in the groups to which they were randomized, regardless of whether they completed the intervention?

• A. Per-protocol analysis
• B. Subgroup analysis
• C. Post-hoc analysis
• D. Intention-to-treat analysis

Answer: (D)

The principle being tested is intention-to-treat analysis: you analyze participants in the groups to which they were randomized, regardless of whether they completed or adhered to the assigned intervention. This preserves randomization, avoids biases from dropping or switching participants, and provides an estimate of real-world effectiveness where not everyone follows the protocol. Per-protocol analysis would exclude non-adherent participants, which can bias results because adherence itself may relate to outcomes. Subgroup analysis looks at specific subsets and can inflate error rates if not pre-specified. Post-hoc analysis is exploratory and mentioned after the fact, risking false positives. By keeping all randomized participants in their original groups, intention-to-treat best meet the scenario described.

The principle being tested is intention-to-treat analysis: you analyze participants in the groups to which they were randomized, regardless of whether they completed or adhered to the assigned intervention. This preserves randomization, avoids biases from dropping or switching participants, and provides an estimate of real-world effectiveness where not everyone follows the protocol. Per-protocol analysis would exclude non-adherent participants, which can bias results because adherence itself may relate to outcomes. Subgroup analysis looks at specific subsets and can inflate error rates if not pre-specified. Post-hoc analysis is exploratory and mentioned after the fact, risking false positives. By keeping all randomized participants in their original groups, intention-to-treat best meet the scenario described.