Using app activity logs reveals more than screen time in smartphone use
Beyond Screen Time: Demonstrating the Value of App Activity Logs to Understand User Behavior Further
Human-Computer Interaction
Summary
Measuring how long people use their smartphones by just looking at total screen time misses important details. The authors show that detailed records of app use—like which apps are opened when and how users switch between them—give a richer picture of behavior. For example, teenagers use apps around their school schedule, a pattern hidden by simple screen time counts. This detailed approach also risks identifying individual users from their app use patterns. The authors highlight how these findings affect research methods and privacy.
What this means in practice
- •For mobile app developers: Design app features and notifications tailored to detailed daily and within-day app usage patterns beyond total screen time.
- •For privacy officers: Assess risks of user re-identification from detailed app activity logs to improve privacy protections.
Authors
Ole Schmitt, Pauline Gieseler, Frederik Riedel, Donatus Wolf, Ariel Stern, Paul Schmiedmayer, David Grüning
Abstract
Research on smartphone use remains fragmented, with studies differing in measures, methods, and platforms, limiting what we know about everyday behavior. We argue that event-level app activity logs should form the backbone of research on actual rather than recalled smartphone use. We conduct a secondary analysis of 4,571,252 app events from 1,972 participants across three longitudinal cohorts differing in age, country, recruitment, and platform, complemented by a published reference cohort. We reproduce established aggregate and micro-usage measures and examine temporal structure, application composition, transitions, and individual distinctiveness. Aggregate usage varies less than the organization of activity: adolescent use, for example, is structured around school schedules, while other cohorts show weaker within-day patterns. Application and transition patterns reveal behavioral differences obscured by screen time; an intervention reduced daily usage while increasing mean session duration. Activity traces also enabled 15-22% top-1 participant re-identification. We discuss methodological, reproducibility, and privacy implications for HCI.