Ever since international large-scale student assessments made it possible to rank countries according to their equitability, Nordic countries have topped these rankings. Nevertheless, a decline in equity has been reported lately. However, the process of empirical enquiry that leads to specific inferences on equity partly stays obscure to education decision-makers. This unawareness of the boundaries of specific methodological and analytical approaches may lead to wrong interpretations and policy implications. Therefore, our aim is to discuss and empirically illustrate how the array of choices taken throughout the research process, from equity conceptualization and operationalization to its measurement, may affect the inferences on educational equity for Nordic countries. Our sample includes fourth- and eighth-grade students from Norway, Sweden, Denmark and Finland who participated in TIMSS 2015. We applied two-level multigroup regression models within the structural equation modelling framework to investigate the sensitivity of the countries’ level of equity to: (a) operationalization of the socioeconomic status measure; (b) operationalization of equity or, in other words, the method of analysis employed (e.g., bivariate analysis versus univariate); (c) single-level against multilevel analytical approaches; (d) the grade/age of students; and (e) the choice of the learning outcome across subject domains. Prior to the analyses, we estimated the comparability of SES as a latent construct between Nordic countries. Our results confirmed that some of the most common choices to measure educational equity do matter. Thus, we would encourage a researcher to report elaborately on the research process and inform on its limitations because if interpreted wrongly, it may have unfavourable consequences for a particular group of individuals.

Students’ motivation in mathematics has been shown to predict their achievement and whether they pursue a later career in STEM (science, technology, engineering, and mathematics). To sustain equity in education, it is important that students are motivated for the STEM fields, independent of their background characteristics (e.g., gender and SES). Previous research has revealed that students’ motivation declines from primary to secondary school. The present study investigates whether this unwanted development may be related to students’ SES, and more importantly, what aspects of teachers’ instruction are related to student motivation for low, medium, and high-SES student groups in grade 5 and 9. We use data from students in grades 5 and 9 and their teachers who participated in TIMSS 2015 in Norway. Multilevel (students and classes), multi-group structural equation modelling is used to answer the research questions. In line with previous research from Germany and the USA, the results showed that SES is more important to student motivation in secondary than primary school, that low SES students’ motivation depends more on their teachers’ instructional quality than high SES students and that this dependency is stronger in secondary school than in primary school. The implications and contributions of the study are discussed.

The prerequisite for meaningful comparisons of educational inequality indicators across immigration status is the comparability of socioeconomic status (SES) measures. The Programme for International Student Assessment (PISA) uses its index of economic, social, and cultural status (ESCS) to provide insights into the problems of inequality across students’ socioeconomic and immigration statuses. However, missing evidence regarding the comparability of the ESCS index or its components across students with and without immigrant background challenges the accuracy of empirical inferences. Our study sheds light on the comparability of the index of household possessions (HOMEPOS) across immigration status in Norway and Sweden—two countries that continue to be two largest recipients of immigration flows among their Nordic neighbours. We tested the PISA 2018 HOMEPOS scale for the overall measurement invariance and possible differential item functioning (DIF) across three student groups with first-generation, second-generation, or no immigrant background. Several HOMEPOS items exhibited DIF within these countries. Moreover, we examined how four strategies to deal with DIF items may affect the inferences regarding educational inequalities across immigration status. The strength of the HOMEPOS–achievement association was sensitive to the choice of approach for 15-year-old immigrant students, while it remained stable and moderate for native students. Our findings encourage researchers using the HOMEPOS scale to consider the invariance testing to avoid measurement bias and provide robust evidence characterizing immigrant achievement gaps.