Past exam of the mathematics course of the University of Cambridge / 2009 / iii / Paper 41 / 1 / f

There was no clear documentation of initiation for $349-328=21$ women, givingThese women may not have received the intervention, although missing documentation is not proof that no contact occurred. Documentation of initiation also does not establish completion or full adherence.

Under intention-to-treat analysis, women retain their randomized arm regardless of actual uptake. Removing nonadherent women would condition on a post-randomization characteristic and could destroy the comparability created by randomization. The resulting estimand is the effect of offering the intervention under the trial's actual adherence pattern. Keeping nonadherent women in their arm does not itself solve missing-outcome problems: the reported 12-week denominators are smaller than the randomized totals, so the outcome analysis still needs an appropriate strategy and assumptions for losses to follow-up.