Currently submitted to: Journal of Medical Internet Research
Date Submitted: Nov 4, 2026
Open Peer Review Period: Nov 4, 2026 - Dec 30, 2026
(currently open for review)
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Feedback and Outcome Measurement in Wearable-Supported Physical Activity Trials: Systematic Methodological Review
ABSTRACT
Background:
Wearable activity trackers can supply both behavioral feedback and trial outcomes. Interpreting their results requires a traceable account of how recordings become an outcome for a particular randomized group and assessment period.
Objective:
To quantify the co-reporting of valid-data rules and analysis samples across feedback–outcome acquisition arrangements, and to examine how source reports link these details to specific outcomes, randomized groups, and periods.
Methods:
Five databases were searched in September 2026; report reassessment ended on October 20, 2026. The register comprised 703 randomized trials. Ten domains retained four evidence states: relevant reporting, information not found, unable to judge, and not applicable. We mapped acquisition arrangements and co-reporting of valid-day rules, non-wear identification, and usable-data denominators. Sensitivity analyses reversed 33 domain updates and four classification updates and examined assessable subsets. Selected original reports illustrated outcome-specific measurement pathways.
Results:
Among 7030 domain assessments, 4806 (68.4%) contained relevant reporting, 762 (10.8%) had information not found, 1456 (20.7%) were unable to judge, and six were not applicable. Acquisition was shared in 305 trials, independent in 192, combined in 57, temporally separate in six, and unclear in 143. The three core domains co-occurred in 135/703 trials (19.2%); reversing all targeted updates yielded 133/703 (18.9%). At least one core domain was unable to judge in 267 trials. Source examples distinguished device-specific rules, observed and modeled samples, and different elapsed times behind the same follow-up label.
Conclusions:
Reporting was more frequent for measurement schedules and device roles than for processing rules and usable-data samples. Linking each recording stream, processing rule, and denominator to its outcome, randomized group, and assessment period would make wearable-derived trial results easier to interpret and reproduce. Clinical Trial: PROSPERO CRD420261512744
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