Objective: Digital reminders are widely used in clinical trials, but their design is rarely evidence-based. We evaluated the effectiveness of two types of digital reminders for trial task completion.
Study design and setting: This randomised Study Within A Trial (SWAT) was embedded in the MEL-SELF trial which evaluates patient-led versus clinician-led melanoma surveillance. SWAT participants were randomised 1:1 to motivation-informed or standard digital reminders for two tasks: monthly health-resource diaries (all participants) and 3-monthly image submissions of self-detected skin lesions (MEL-SELF intervention arm only). Primary outcomes were the per-participant proportion of diaries completed on time (within 14 days) and images completed on time (42 days). Secondary outcomes were on-time completion of the first diary and first scheduled image, any-time completion, time to completion, number of reminders required, and costs.
Results: Between 16 August 2023 and 3 June 2024, 260 participants were randomised to motivation-informed (n = 130) or standard (n = 130) reminders. On-time completion of the first diary was 82% (106/130) for both reminder types (Risk Difference (RD): 0.0%; 95% CI, -9.5% to 9.5%) and any-time per-participant diary completion was also high (median 100% both arms). Across 2,821 diary submission tasks, participants received 5,710 automated reminders (mean 2.0 per task), with 21.6% requiring staff follow-up; mean cost per completed diary was AUD 4.15. For images, on-time first submission was 51% (33/65) in the motivation-informed arm and 57% (36/63) in the standard arm (RD: -6.3%; 95% CI, -22.9% to 10.6%); per-participant any-time completion of scheduled image submissions was also modest in both arms (median 50% motivation-informed vs 67% standard). For 489 image episodes, there were 1,929 automated reminders (mean 3.9 per episode); 56.0% required trial staff follow-up, and the mean cost per submitted image was AUD 17.43. In prespecified subgroups, differences between reminder arms were small, with diary completion higher in both SWAT arms for participants in the MEL-SELF control arm compared with the intervention arm.
Conclusion: Motivation-informed reminders did not improve completion of trial tasks compared with standard wording. For low-complexity tasks, standard reminders may be sufficient; for high-complexity tasks, changing message content alone is unlikely to offset burden or logistical barriers.
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- Motivation-informed digital reminders were no more effective than standard reminders for trial task completion in a randomised Study Within A Trial (SWAT)
- Deonna M. AckermannEllie MedcalfKaren BrackenRobin M. TurnerJolyn K. HerschMonika JandaKaty J.L. Bell
- Biostatistics Centre (DSM)
- Journal of clinical epidemiology, Vol.195, 112263
- Elsevier
- 31/03/2026
- Refer to article for funding information
- Copyright © The Author(s) 2026. This work was first published in Journal of Clinical Epidemiology (Elsevier). This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (https://www.creativecommons.org/licenses/by/4.0/), which permits unrestricted use, sharing, adaptation, distribution and reproduction in any medium or format, provided that the original work is properly attributed to the creator(s) and the source, a link to the Creative Commons license is provided, and any changes made are indicated.
- English
- Journal article