Het in Kaart Brengen van Domein-Specifieke School Diversiteitsmodellen en Hun Implicaties: Wanneer en Waarom Alle Leerlingen Zich Kunnen Thuis voelen en Kunnen Presteren

Large ethnic educational disparities persists, with minoritized students consistently experiencing lower school belonging and academic achievement compared to their ethnic majority peers. The current dissertation integrates insights from school effectiveness research and social and cultural psychology to examine the role schools play in these disparities. Specifically, I here focus on the ways in which primary schools approach ethnic-cultural diversity, as reflected in different School Diversity Models (SDMs) of assimilationism, color-blindness and pluralism which respectively involve reducing, ignoring and valuing ethnic-cultural diversity. Despite advancements in the field, at least three important limitations remain, which I aim to tackle in the current mixed-methods dissertation. The first limitation lies in the conceptualization of SDMs as general and abstract ideologies, which contrasts with qualitative studies that highlight the importance of distinguishing the concrete practices of SDMs across various domains such as language, religion, curriculum, and student identities. Therefore, my first aim is to develop a comprehensive framework to understand how schools may apply the three aforementioned diversity models (in all their sub-facets) to these different domains (Aim 1a), to test whether it is statistically possible to distinguish these domains (Aim 1b), and to develop reliable and valid measurement tools to capture perceived SDMs in a domain-specific manner (Aim 1c). Second, and important for future intervention studies and school policies, we lack insight into how specific diversity practices are associated with students' school belonging and achievement. Therefore, using a large-scale quantitative survey, I aim to test if the same SDMs applied to different domains have different implications for school belonging and achievement, and whether this is the same for minoritized and majority students (Aim 2). Finally, students' voices are largely absent from SDM studies, which is why I aim to conduct focus groups to gain insight into how students evaluate and discuss specific diversity practices across domains, as well as the reasons behind their evaluations (Aim 3). In the first empirical chapter (Chapter 2), I develop the conceptual framework (Aim 1a) and, using data collected among 309 teachers, I demonstrate the statistical importance of distinguishing the domains of SDMs (Aim 1b). I build on these findings to develop and validate novel measurement scales in Chapter 3, using data from 3073 10-12 year old students and 816 teachers in 59 Flemish primary schools (Aim 1c). I find these scales to be reliable and valid for capturing individual-level perceptions and students' shared school-level perceptions of SDMs. However, they are not suitable for capturing teachers' shared perceptions of SDMs or actually implemented SDMs, possibly due to the large disagreement among participants within schools. Regarding the implications of SDMs for students, and drawing on the large-scale quantitative student data, Chapter 4 reveals that perceptions of pluralism are, across domains, related to more school belonging and sometimes also to higher math achievement, while perceptions of assimilationism are consistently negatively related to school belonging and, depending on the domain, negatively or unrelated with math achievement. Links between students' perceptions of color-blindness and outcomes are strongly dependent on the domain, and are sometimes positive, insignificant or negative. Although some perceived practices are more strongly related to the school belonging of minoritized students, patterns are mostly similar for minoritized and majority students. In Chapter 5, and addressing Aim 3, I show that students primarily appreciate pluralist practices because, unlike assimilationist practices, they allow for the expression of their authentic selves, ensure equal treatment, and facilitate learning about diversity. Color-blind practices are viewed more positively than assimilationist practices because they aim to achieve equal treatment, even though they do not allow for the expression of students' authentic selves. These evaluations and arguments did not vary according to students' ethnic background. Together, my PhD studies fuel the integration of SDM studies into the School Effectiveness Research tradition and hold several implications for the conceptualization and operationalization of SDMs in future studies. They also bear implications for educational policy makers and practitioners: while concrete diversity practices relate to school belonging and achievement in slightly different ways depending on the domain, pluralist practices that value and embrace students' ethnic-culturaldiversity hold most promise to ensure the thriving of all students.