Longitudinal and differential effects of differentiated instruction on academic achievement and subjective well-being in inclusive secondary education

Background Differentiated instruction (DI) is a fundamental component of teaching quality, particularly in diverse and inclusive classrooms. While DI has been shown to enhance students' academic achievement, research at the secondary education level remains limited, and its impact on students’ subjective well-being—widely recognized as essential for learning—has been largely unexplored. Moreover, effects may differ for students with special educational needs in learning (SEN-L). Aim This study investigated cross-sectional and longitudinal effects of classroom-level DI practices on students’ academic achievement and subjective well-being in lower secondary education, incorporating both student and teacher perspectives. Additionally, it examined whether the effects of DI differ between students with and without SEN-L. Sample Data were drawn from a longitudinal study with three measurement occasions (Grades 6, 7, and 9). The sample comprised 4654 sixth-grade students, along with 417 German and 398 mathematics teachers. Methods Multilevel regression analyses with latent variables were conducted to investigate cross-sectional effects. To examine longitudinal effects, latent neighbor change models were applied. Results Cross-sectionally, DI showed some small positive associations with academic achievement and, particularly student-reported DI, small positive associations with subjective well-being. DI predicted some changes in both outcomes over time, albeit inconsistently and with small-to-negligible effect sizes. The findings indicate only two small differential effects for students with SEN-L compared to other students. Conclusions The study extends research on DI by focusing on both students’ academic achievement and subjective well-being in lower secondary education, while calling for continued research into its longitudinal effects and underlying mechanisms.