Addressing Heterogeneity in Research: A Systematic Review of Evening Mobile Media Use and Sleep

Research has long documented adverse associations between evening mobile media use and sleep. Yet growing evidence from studies employing more diverse and rigorous methods reveals a more heterogeneous and methodologically complex picture. Existing reviews have rarely examined how such methodological variation contributes to heterogeneity in reported outcomes. To address this gap, the present review adopts a methodological lens to synthesize 76 studies on evening and presleep mobile media use, examining how conceptual, operational, and design-related factors shape reported findings. The reviewed studies were conducted across multiple countries in North America, Europe, Asia, the Middle East, and Africa and predominantly examined adolescent and young adult samples. Results indicate that risk-oriented conceptualizations prevail, and detrimental outcomes are most frequently reported in cross-sectional self-report studies, whereas null or mixed results emerge when objective, within-person, or fine-grained measures are applied. These patterns suggest that the field’s heterogeneity largely reflects systematic methodological variation rather than substantive disagreement. By distinguishing what is measured, how it is measured, and when, this review illustrates how methodological choices could shape which effects come to dominate the field, contributing to a more precise and context-sensitive understanding of how mobile media use relates to sleep.