Abstract
Debate over whether smartphone use relates to poorer well-being is limited by self-reports, small single-country samples, and a focus on average use. We harmonized objective app-use from 12 studies (2,945 participants; 37,229 person-days; 851,865 person-hours) across five countries to examine associations of well-being with smartphone use and its variability. Additionally, we examined variations in smartphone use across age, gender identity, and time-of-day and day-of-week. Daily, participants averaged 3.27 hours of use (SD = 2.28), accessed 15.9 apps (SD = 6.16), and were unstable (40.6% of the total variation accounted for by within-person changes). Poorer well-being was associated with longer, more variable use; a depressive symptom increase of 10% of the scale range corresponded to 7 additional minutes of daily use and 7.5% higher within-person variance. Overall, younger persons and women used their phones more frequently, and higher wellbeing was related to consistently lower smartphone usage.