Towards ethical surveillance of smartphone use among youth: exploratory digital citizen science approaches shaping the understanding of ubiquitous technology use

Smartphones are widely used among youth, yet no standardized measures accurately capture smartphone use. This exploratory study utilized the Smart Platform, a digital citizen science initiative, to collect objective, real-time data on smartphone use among youth and investigate differences between retrospective and objective measurements. Youth self-reported smartphone use retrospectively via a validated questionnaire, while objective use (i.e., duration and day of use) was captured over one week using a custom-built app. Differences between the two measures were assessed using Wilcoxon signed-rank test and linear mixed effects models and visualized with Bland-Altman plots. A total of 85 participants with 257 observations (mean age = 15.65, SD = 1.68) were included in this study. Retrospective smartphone use was higher than objective use in the overall sample (4.074 vs 2.615 hours/day, p = 0.019), on weekdays (3.973 vs. 2.714 hours/day, p = 0.024) and on weekends (4.026 vs. 2.323 hours/day, p = 0.014). The mean difference between the measures was 1.39 hours/day (95% CI [-6.99, 9.76]), with larger differences at higher use levels. Mixed effects models confirmed the difference between retrospective and objective use (β = 1.341, C.I. [0.637, 2.071], p < 0.001), adjusting for sociodemographic factors. Females also reported higher use than males (β = 1.027, C.I. [0.068, 1.985], p = 0.045). Accurate measurement of smartphone use is imperative to understand its impacts among youth. Privacy and security challenges associated with objective measures can be addressed through digital citizen science, where youth have the power to share, withdraw, or delete their data.