Using the Internet to access key populations in ecological momentary assessment research: Comparing adherence, reactivity, and erratic responding across those enrolled remotely versus in-person.

Ecological momentary assessment (EMA) is a set of longitudinal methods that researchers can use to understand complex processes (e.g., health, behavior, emotion) in "high resolution." Although technology has made EMA data collection easier, concerns remain about the consistency and quality of data collected from participants who are enrolled and followed online. In this study, we used EMA data from a larger study on HIV-risk behavior among men who have sex with men (MSM) to explore whether several indicators of data consistency/quality differed across those who elected to enroll in-person and those enrolled online. One hundred MSM (age 18-54) completed a 30-day EMA study. Forty-five of these participants chose to enroll online. There were no statistically significant differences in response rates for any survey type (e.g., daily diary [DD], experience sampling [ES], event-contingent [EC]) across participants who enrolled in-person versus online. DD and ES survey response rates were consistent across the study and did not differ between groups. EC response rates fell sharply across the study, but this pattern was also consistent across groups. Participants' responses on the DD were generally consistent with a poststudy follow-up Timeline Followback (TLFB) with some underreporting on the TLFB, but this pattern was consistent across both groups. In this sample of well-educated, mostly White MSM recruited from urban areas, EMA data collected from participants followed online was as consistent, reliable, and valid as data collected from participants followed in-person. These findings yield important insights about best practices for EMA studies with cautions regarding generalizability. (PsycInfo Database Record (c) 2020 APA, all rights reserved).