The smartphone addiction degree estimation scale: Enhancing assessment and understanding of gender differences in youth

Current psychometric instruments for assessing smartphone addiction often fail to account adequately for age and gender differences, largely due to their reliance on traditional factor analytic approaches. This study employs a sequential application of Factor Analysis and Item Response Theory to develop a brief smartphone addiction scale for individuals aged 18–25 that can be flexibly applied according to the severity of addiction exhibited by the individual. The original 42-item questionnaire was administered to a sample of 1994 European university students. Results supported a three-factor structure consistent with core components of substance addiction: Tolerance/Control Deficit, Withdrawal Syndrome, and Negative Consequences. A fourth factor related to physical and health consequences was successfully integrated into the Negative Consequences factor without compromising model fit or reliability. The incorporation of Item Response Theory enhanced measurement precision by transforming the instrument into an adaptive test capable of estimating smartphone addiction severity based on individual response patterns. The final scale retained 20 of the original 42 items while maintaining strong psychometric properties. Application of the scale to the analysis of gender differences in smartphone addiction demonstrated that substantive conclusions vary depending on the analytical framework employed, helping to explain inconsistencies reported in the existing literature. Gender-specific analyses indicated that men were more likely to report productivity loss and reduced social opportunities, whereas women more frequently endorsed smartphone use as a strategy for coping with negative emotional states. Overall, the proposed Smartphone Addiction Degree Estimation Scale (SADES) shows strong potential as a reliable tool for epidemiological research and for informing public health interventions targeting problematic smartphone use.