Educational transitions are pivotal phases during which peer networks are reorganized and social positions are renegotiated (Lorijn et al., 2024). From a developmental and relational perspective, heightened uncertainty during such periods may intensify social exclusion and contribute to inequalities. At the same time, transitions create opportunities for supportive peer relationships that can facilitate adjustment, participation, and well-being (Brenner et al., 2017). Network-based approaches conceptualize classrooms as dynamic relational systems where micro-level interaction patterns aggregate into more stable structures that shape students’ access to social resources (Freire et al., 2024). Despite growing interest in the development of peer networks, there is limited empirical evidence on short-term network changes during transition phases and on the role of teachers’ diagnostic and instructional practices in shaping these processes (Veenstra & Laninga-Wijnen, 2022). To address this research gap, the present study examines changes in peer networks in 17 fifth-grade classes (N = 299) at the beginning of the 2025/26 school year. Using a longitudinal experimental intervention design with an intervention group and a waitlist control group, the project aims to strengthen teachers’ competencies in assessing students’ social networks and using these diagnoses to inform pedagogical decision-making. Peer networks are assessed through sociometric nominations and ratings of interaction frequency, which are complemented by psychometric measures of classroom cohesion, perceived friendship quality, and social participation. Both data sources are integrated to tailor the intervention. Network analysis helps teachers identify central students, those occupying bridging positions between groups, and students at risk of marginalization. Complementary psychometric data provide insights into students’ subjective perceptions of their social situation, helping to determine whether pedagogical action is required. Results from the first measurement wave reveal substantial between-class differences in network structure (e.g., density, fragmentation, centralization) and in the perceived classroom social climate. Moreover, systematic group-specific discrepancies in sociometric integration emerge. Boys and students with special educational needs exhibit significantly lower levels of network embeddedness, whereas gender-diverse students display comparatively high indegree values in descriptive terms, indicating better social integration within the classes. By the time of presentation, longitudinal comparative analyses will be available to identify overall trends, group-specific dynamics, and intervention effects, focusing on changes in network indicators and evolving patterns of inclusion and marginalization. By integrating structural network indicators and psychometric measures, the study contributes to the symposium’s aim of advancing the understanding of how quantitative and qualitative dimensions of peer relations interact over time.

Benner, A. D., Boyle, A. E., & Bakhtiari, F. (2017). Understanding students’ transition to high school: Demographic variation and the role of supportive relationships. Journal of Youth and Adolescence, 46(10), 2129–2142. Freire, S., Roçadas, C., Pipa, J., & Aguiar, C. (2024). Classroom social networks, students' peer‐related social experiences and sense of belonging: The specific case of students with SEN. British Educational Research Journal, 50(4), 1617-1635. Lorijn, S. J., Zwier, D., Laninga-Wijnen, L., Huisman, M., & Veenstra, R. (2024). A new school, a fresh start? Change and stability in peer relationships and academic performance in the transition from primary to secondary school. Journal of Youth and Adolescence, 53(9), 1987–2001. Veenstra, R., & Laninga-Wijnen, L. (2022). Peer network studies and interventions in adolescence. Current Opinion in Psychology, 44, 157-163.