LAUSR

Mobile health (mHealth) apps show potential contributions as interactive systems for managing users' health conditions. They are also used to improve health habits using behaviour change strategies. However, the trends, effectiveness, and design practices of these apps in terms of behaviour change are unclear yet. With a collaboration between researchers, domain experts, interactive systems developers and professionals, this paper aims to fill this gap by systematically investigating 70 mHealth apps using two popular behaviour change frameworks, namely App Behaviour Change Scale (ABACUS) and the Persuasive System Design (PSD) model. The study investigates the most common strategies and how these strategies were designed and implemented in the apps to achieve the targeted design objectives. Furthermore, the study evaluates apps' behaviour change potential using the behaviour Change Score (BCS), a measure we introduced to evaluate how the apps employ behaviour change strategies. The results show that 1) Journaling is the most common category of apps. 2) the most employed strategies are Self-monitoring, Customize and Personalize, and Reminders. And 3) there is a positive correlation between apps' ranks (based on ratings and installation) and the BCS score of most strategies. Based on our findings, we offer recommendations for designing and developing mHealth apps and present opportunities for future work in this area.