nam a22 4500 530200104 20181026074424.0 cr unu---uuuuu 181026e20190214xx s 000 0 eng 10.3929/ethz-b-000297994 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/297994 (ALEXREPO)oai:www.alexandria.unisg.ch:255415 Trajectories of Engagement with a Digital Physical Activity Coach: Secondary Analysis of a Micro-Randomized Trial [Elektronische Daten] [Jan-Niklas Kramer, Florian Künzler, Peter Tinschert, Tobias Kowatsch] 2019 2 p. Open access ethresearch Context: Intervention components of a MobileCoach based smartphone app to promote walking were assessed in a seven-week micro-randomized trial (N = 274). In order to make a significant contribution to public health, the app must also engage those at higher risk for adverse health outcomes, i.e. elderly, less active or less healthy participants. Methods: In a secondary analysis, longitudinal trajectories of participants' number of daily app sessions were clustered using the k-means algorithm with an alternating number of clusters. An app session was defined as any interaction between a participant and the app separated by at least five minutes between interactions. The final number of clusters was determined based on five different clustering quality criteria. Results: Two different clusters emerged: stable high engagement (31.3% of participants, 7.6 (SD = 2.9) mean daily app sessions) and stable low engagement (68.7% of participants, 1.5 (SD = 1.4) mean daily app sessions). Highly engaged participants were older (45.8 vs. 40.1 years, p < .001, d = 0.43) and accumulated more steps per day during the study (7373 vs. 5828 steps per day, p < .001, d = 0.57). Clusters did not differ with regard to participants' baseline physical activity, gender, body mass index, self-reported health status or education. Conclusions: A chatbot-based walking app engaged participants of a micro-randomized trial over a period of seven weeks independent of their risk for adverse health outcomes. Thus, participants with low risk for adverse health outcomes at baseline do not drive high engagement with the app. 10th International Society for Research on Internet Interventions Scientific Meeting: The Next Generation (ISRII 2019) in Auckland, New Zealand (February 13-15, 2019) In Copyright - Non-Commercial Use Permitted http://rightsstatements.org/page/InC-NC/1.0 ethresearch other research area alexrepo Kramer Jan-Niklas joint author Künzler Florian joint author Tinschert Peter joint author Kowatsch Tobias joint author http://hdl.handle.net/20.500.11850/297994 text/html WWW-Backlink auf das Repository (Open access) 1 Other Conference Item ethresearch NonPeerReviewed alexrepo peerstatus ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/297994 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Kramer Jan-Niklas joint author ETHRESEARCH 700 1- Künzler Florian joint author ETHRESEARCH 700 1- Tinschert Peter joint author ETHRESEARCH 700 1- Kowatsch Tobias joint author ALEXREPO 856 40 https://www.alexandria.unisg.ch/255415/1/Kramer%2C%20Jan-Niklas.%20Trajectories%20of%20Engagement%20with.pdf text/html WWW-Backlink auf das Repository ALEXREPO 700 1- Kramer Jan-Niklas joint author ALEXREPO 700 1- Künzler Florian joint author ALEXREPO 700 1- Tinschert Peter joint author ALEXREPO 700 1- Kowatsch Tobias joint author CL050000 XL050000 XC000500 ETHRESEARCH ETHRESEARCH ETHRESEARCH Other Conference Item Open access ALEXREPO ALEXREPO ALEXREPO Conference or Workshop Item