Nordic education systems have long been associated with equity, social cohesion, and a strong commitment to providing equal learning opportunities for all students (Blossing et al., 2014; Imsen et al., 2017). Educational equity, understood as ensuring fair access to learning regardless of students’ background and providing learners with what they need, remains a core principle of this model (Levinson et al., 2022). Over recent decades, however, demographic change driven by migration, refugee movements, and broader social transformations has reshaped student populations and the everyday conditions of teaching, particularly in urban contexts (Brussino et al., 2021; OECD, 2023). Classrooms are becoming more heterogeneous along multiple dimensions, including students’ migration background, ethnicity, special educational needs, and socio-economic circumstances (Nilsen et al., 2025; Olsen & Hanssen, 2024; Teig et al., 2024). Rising socioeconomic and ethnic inequalities in student outcomes, alongside increasing school segregation by migration background, academic achievement, and socioeconomic status further contribute to this complexity in the Nordic countries (Nilsen et al., 2025; Sandsør et al., 2023; Yang Hansen et al., 2025).
As a result, Nordic classrooms are more diverse than earlier, and there is wide variation in language proficiency, academic readiness, special education needs, and social resources. These developments do not simply challenge established equity goals, but they also reconfigure what it means to teach in Nordic classrooms (Nilsen et al., 2025; Teig et al., 2024). Prior research shows that heterogeneity does not have negative effects by itself. Its consequences depend on mediating factors such as instructional quality, learning culture, and classroom management (Weintraub, 1997). Higher levels of diversity may therefore require adjustments in pedagogical, relational, and organizational practices, to avoid a decline in educational conditions. In turn, these shifts place new demands on teacher education, ongoing professional development, and support structures that can equip teachers to respond effectively to more complex classroom realities.
Against this background, the present study examines whether teachers’ professional outcomes (workload, well-being, job satisfaction with the school environment, need for professional development for teaching for diversity, student behaviour stress) have changed over time (from 2018 to 2024) and whether any such changes are mediated by the changes in classroom composition. To do so, we use data from the last two cycles (year 2018 and year 2024) of the Teaching and Learning International Survey (TALIS) across four Nordic countries. Classroom composition is treated as a potential mediating factor, allowing us to investigate which of its aspects mediate changes over time in teachers’ outcomes. Thus, we answer the following research questions:

RQ1: How have teachers’ workload, well-being, job satisfaction with the school environment, need for professional development for teaching for diversity and student behaviour stress changed from 2018 to 2024 in each of the Nordic countries?

RQ2: Among outcomes that exhibit change over time, to what extent are these changes associated with changes in classroom composition?

We use data from the two most recent TALIS cycles (2018 and 2024) in four Nordic countries: Denmark, Finland, Norway, and Sweden. TALIS employs a stratified two-stage probability sampling design to obtain nationally representative samples of lower secondary teachers and principals. Further details on the sampling design are provided in the TALIS technical report (OECD, forthcoming). The final sample in this study includes 11788 teachers in 2018 and 11713 teachers in 2024. Data from the two cycles were combined into a single dataset including a dummy variable for the TALIS cycle/time (1 = 2018, 2 = 2024). Teacher outcomes (workload, well-being, job satisfaction with the school environment, need for professional development for teaching for diversity, student behaviour stress) were assessed using established TALIS scales that include three or four items each, all rated on a four-point Likert-type scale reflecting degree or extent. Classroom composition was measured using teachers’ estimates of the proportion of students in the class with selected characteristics (students whose first language is different from the language of instruction, low academic achievers, students with special needs, students with behavioral problems, socio-economic disadvantaged students, and students who are refugees), reported on a five-category percentage scale. Response categories were harmonized across 2018 and 2024. Data were prepared in R version 4.5.2, and analyses were conducted in Mplus 8.11 (Muthen & Muthen, 2017; R Core Team, 2025). The hierarchical structure of teachers nested within schools was addressed using TYPE = COMPLEX with schools as the clustering variable, and teacher weights were applied. The study follows a repeated cross-sectional trend design rather than a longitudinal design. This means that different teachers are surveyed in each country at each time point, but both samples were representative of teachers at the level of the country. Analyses include several steps. CFA and multigroup CFA are used to assess reliability and measurement invariance of each latent construct across 2018 and 2024. A mediation SEM framework is used to examine whether changes in classroom composition account for observed changes in teacher outcomes, inspired by prior work on system-level changes using repeated cross-sectional designs (e.g., Gustafsson & Nilsen, 2016). Initial models estimated changes in outcomes and mediators over time. For outcomes that changed, we tested whether classroom composition mediated these changes, accounting for the sampling design and clustering.

Preliminary results show stable job satisfaction and workload across Nordic countries from 2018 to 2024 while teacher well-being worsened only in Norway and Finland. At the same time, student behavioral stress and teachers’ need for professional development increased similarly across the four Nordic countries. We also found differences across the countries in terms of changes in classroom composition. Denmark and Finland saw increases in low-achieving students, students with special needs, and students with behavioral problems, while other categories remained stable. Norway showed increases across all categories, and Sweden only in low-achieving students. Some categories changed together, due to positive, moderate correlations between them e.g., low-achieving students and students with special needs and students with behavioral problems. Preliminary mediation analyses, examining the role of low-achieving students only, indicate that these changes partially accounted for the increase in teachers’ student behavioral stress in Denmark (β = 0.017, p = .027), Finland (β = 0.014, p < .001), and Norway (β = 0.031, p < .001), but not in Sweden (β = 0.010, p = .087). These findings align with prior research suggesting that classroom heterogeneity can contribute to teacher stress, though other factors are also involved. Similarly, changes in low-achieving students partially explained declines in teacher well-being in Norway (β = 0.025, p < .001) and Finland (β = 0.007, p = .002), indicating that classroom composition contributed modestly to reductions in well-being. However, the majority of the decrease in teacher well-being occurred independently of classroom composition, suggesting that other factors, such as workload, instructional challenges, or broader organizational conditions, also play an important role. Further analyses are ongoing and will examine the full set of mediators and outcomes, enabling a more comprehensive understanding of how evolving classroom heterogeneity shapes teacher well-being, professional development needs, and stress across the Nordic countries

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