Designing in-app messages to nudge behavior change: Lessons learned from a weight management app for young adults

Abstract

While mobile-based behavioral weight loss apps are increasing, little is known about factors associated with likelihood of viewing in-app messages. The objectives of this study were to examine, among 52 young adults participating in a microrandomized trial testing smartphone-delivered messages promoting weight management behaviors, the proportion of intervention messages viewed and behavioral predictors of message viewing. Two thirds of messages delivered were viewed. Messages were less likely to be viewed over time in the program and as participants’ total weight change in the program increased. Lapses in self-weighing and increased weight since the last weighing observation were associated with decreased probability of message viewing. Conversely, increased days of meeting dietary goals in the last 7 days were associated with increased likelihood that a message was viewed. These findings identified circumstances in which messages are less likely to be viewed and have implications for designing mobile approaches to enhance participant engagement.