Adolescents' academic engagement mediates the association between Internet addiction and academic achievement

Although the association between Internet addiction and academic achievement has been widely observed in adolescents in recent years, little is known about the mechanisms of Internet addiction and its adverse effects on academic achievement in terms of individual factors and classroom contexts. The present study examined the relationship between Internet addiction and academic outcomes, the mediating role of academic engagement, and the cross-level moderating effect of classroom achievement norm. By using a short-term longitudinal design, two-wave data were obtained from 2407 students from 47 classes in China over six-months. A multilevel structural equation model was used to explain the nested data structure. Results indicated that the negative effect of Internet addiction on adolescents' later academic achievement was mediated by academic engagement and disaffection at the individual level. Furthermore, classroom achievement norm moderated the association between academic disaffection and achievement, with a significant indirect effect in the high classroom achievement norm classes and a non-significant effect in the low classroom achievement norm classes. These results held after controlling for an individual's gender, age and academic achievement in the first term at the individual level and the class size and school at the classroom level. In conclusion, this study reveals the internal mechanism of how students' Internet addiction leads to the decline of academic achievement. It also provids a practical and effective outlook on the prevention and intervention of the negative effects of Internet addiction in the future teaching practice from the perspective of personal motivation and classroom environment. • The effect of Internet addiction on achievement is via engagement and disaffection. • Classroom achievement norm moderates the influence of disaffection on achievement. • Disaffection's indirect effect appears only in the high achievement norm classes.