Comparison Of Reported Timing Of Ecological Momentary Assessments Of Physical Activity With Survey Metadata

PURPOSE: Event-based Ecological Momentary Assessment is used to capture an individual’s experience of physical activity (PA) in a proximal context, often using smartphones to complete Internet-based surveys. This method is contingent on participants’ compliance in reporting momentary states. The purpose of this analysis is to explore alignment between participants’ reported survey timing and time-stamped survey meta-data. METHODS: In the parent study, participants completed a pre-activity survey (PreS) and a post-activity survey (PostS) for all purposeful PA over 10-weeks (at least 10 minutes). Retroactive surveys (RetroS) could be initiated when momentary reporting was not possible. In addition to reporting total PA duration, PreS and PostS items allowed participants to indicate the timing of their report relative to the start and finish of the PA session (immediately/within 10-min, within 10-30-min, more than 30-min from start/finish). The survey software provided the date and time of each survey initiation and completion. Basic frequency and descriptive statistics were conducted to summarize the proportion of PreS and PostS reports completed more than 30-min outside the activity session and RetroS. Of the momentary reports, the expected timeframe for reporting (i.e., reported PA duration plus participant-reported time lags in completing PreS and PostS) was compared to the meta-data timeframe of PreS to PostS completion to explore degree of alignment. RESULTS: Of the 229 bouts reported by 8 participants, 42% were documented using RetroS (mean time lag following PA = 8.61±7.12 hours). Of the 137 sessions documented using PreS and PostS, 24% indicated survey completion more than 30-min outside of the PA session (all specific to PostS; mean time lag = 5.24±3.04 hours). Alignment between participant-reporting timing and meta-data was noted in 92.3% of the 104 sessions characterized by PreS and PostS completed within 30-min of PA session start and finish. CONCLUSION: Less than half of the sessions were documented with reasonable proximity. When relying on participant-initiated reports, it may be prudent to examine research results with and without retrospective data. If impactful, loss of momentary event-contingent PA data should be accounted for in participant recruitment and study duration.