Who stays and who plays? Participant retention and smartphone app usage in a longitudinal travel survey.

Abstract

Longitudinal studies have become increasingly popular for investigating changes in behaviour, but present additional challenges around participant recruitment, retention, compliance, and ultimately data quality. Personal technologies, particularly smartphones, have become integral to tackling these challenges but come with their own caveats around user acceptance and compliance. The current paper investigates these issues in the context of a longitudinal investigation of interventions designed to encourage use of public transport and increase associated physical activity in Tasmania, Australia. The study comprises multiple waves of data collection over a seven-month period in which travel data were collected using a smartphone app and supplemented with user experience surveys. Evidently attrition is lower for older participants, those engaging with the app more, and those responding to the research/environmental/health messaging of the survey as well as the potential for financial gain. App usage is lower among older participants while app engagement is stronger for males, those recording less travel and those indicating environmental reasons as a motivator for completing the study. Experiences with the app were mixed, participants reported positive sentiments about the ease of use, hedonic motivation, and help in recalling travel; however, concerns were raised over the accuracy of trip recording, the associated burden of correcting trips, and reductions in smartphone battery-life. Despite the unplanned coincidence with the COVID-19 restrictions, outcomes provide important guidance around recruitment, retention and post-hoc analysis of results from longitudinal studies.