Abstract
BACKGROUND: We conducted a pilot ecological momentary assessment (EMA) study in preparation for a prospective cohort study of the drivers of syphilis transmission among sexual minority men. Our objectives were: (1) evaluate the effect of monetary compensation (any versus no compensation and amount paid per survey) on participant responsiveness, and (2) evaluate acceptability and feasibility of the EMA smartphone app to capture sexual and other behaviors in the last 24 hours. METHODS: We enrolled 40 men in the 4-week pilot and assigned them to 1 of 2 groups (higher vs lower compensation). Participants completed daily surveys by responding to push notifications or self-initiating in the app. Participants received $5, $3, or $0 per survey depending on compensation group, survey type, and study week. We evaluated response rates overall, by compensation group, and over time, and described responses to a follow-up survey assessing acceptability and feasibility. RESULTS: The overall median completion rate was 60.7%. The higher compensation group had higher completion rates for self-initiated surveys, which only they were paid for (median 75% vs 43%, P < 0.001). For study-initiated surveys, which both groups were paid for (but the higher compensation group slightly more), the lower compensation group had somewhat higher completion rates (median 94% vs 75%; P = 0.13). Response rates among both groups decreased over time. CONCLUSIONS: Responsiveness to daily EMA surveys was higher when participants received compensation. The amount received per survey appeared to be less important. Ecological momentary assessment may be a resource-effective supplement to traditional data collection methodologies in sexual health research.