Wullschleger, AndreaMaag Merki, KatharinaGrob, UrsRechsteiner, BeatCompagnoni, MiriamVörös, András2025-03-042025-060959-47521873-326310.1016/j.learninstruc.2025.102104https://irf.fhnw.ch/handle/11654/50483https://doi.org/10.26041/fhnw-12015Background Previous research on the relationship between teacher collaboration and student achievement yielded ambiguous results. From a theoretical perspective, an indirect association between high-quality teacher collaboration and student achievement is assumed, mediated by instructional quality. However, empirical evidence for this assumed theoretical mediation model is lacking. Aim This study analyses the relationship between the extent of high-quality teacher collaboration reported by teachers via social network ties and the development of fifth-grade students’ mathematics achievement over one school year. It examines whether and how this relationship is mediated by instructional quality assessed as effective teaching from the perspective of the students. Sample The sample included 80 primary school teachers and 770 fifth-grade students from the German-speaking part of Switzerland. Method A two-level structural equation model was applied, comprising two latent change models, one for instructional quality and one for mathematics achievement, to examine student survey data on instructional quality, student mathematics achievement tests, and teacher social network survey data on perceived high-quality teacher collaboration. Results The results revealed a significant positive indirect effect between high-quality teacher collaboration and student achievement, mediated by instructional quality. However, the direct effect between high-quality teacher collaboration and mathematics achievement, although positive, was not significant. Both the total and indirect effects of the model were significant. Conclusion This study underpins and extends previous findings emphasizing the significance of perceived high-quality teacher collaboration by demonstrating that these collaborations are crucial for fostering instructional quality and students’ mathematics achievement.enTeacher collaborationSocial networksInstructional qualityMathematics achievementMultilevel longitudinal mediation model370 - Erziehung, Schul- und Bildungswesen01A - Beitrag in wissenschaftlicher Zeitschrift