The relationship between student socioeconomic status (SES) and achievement is apparent in almost every educational system across the world. In the Nordic educational systems, although it may be weaker than other countries, SES is yet one of the strongest predictors of academic achievement (Sirin, 2005). Few studies, such as Myrberg & Rosén (2009), explore the direct and indirect effects of various factors on the relationship between SES and student achievement. Further investigation into these mechanisms is necessary, as SES is mostly used to control for selection bias (Gustafsson, Nilsen, & Hansen, 2018).

Given the Nordic educational systems’ aim of increasing equity, an important apsect to investigate is to what degree teacher related factors influence the relationship between student SES and achievement. Previous studies have indicated that teachers account for a significant portion of variance in achievement between classrooms (Darling-Hammond, 2014). Indeed, there is a consensus that teachers are a crucial school factor, and their competence is the foundation of high-quality schools, instruction, and learning (Blömeke, Olsen & Suhl, 2016). Teacher competence (e.g., higher quality instruction, efficient classroom management etc.) positively affects student achievement (Kelcey et al., 2019) and overall may have a positive effect on reducing inequity in education (Wößmann, 2008). 

Specifically, an essential characteristic for effective teachers lies in their ability to deliver quality instruction, by explaining the content clearly and assessing student understanding of the subject matter (Ferguson, 2012). While instruction quality is related with student motivation, it has been documented to be positively related with student achievement in mathematics (Bergem, Nilsen & Scherer, 2016). This is an important aspect, especially in Sweden, where challenges arise due to the unequal distribution of well-qualified teachers across schools, leading to a widening achievement gap between schools and student groups (Yang Hansen & Gustafsson, 2019). Further, not many studies have investigated the effect that instructional quality has on the relationship between student SES and achievement in Nordic educational systems. Also, a limited number of studies have utilized representative International Large-Scale Assessment (ILSA) data in this context.

Thus, the main objective of the present study is to investigate how instructional quality relate to equity in education. Specifically, the study focuses on how student perceptions of instructional quality may mediate or moderate the relationship between SES and eighth grade students’ math achievement in the Swedish educational system. This study is grounded in the Dynamic Model of Educational Effectiveness theory that explores factors influencing student outcomes across all school levels, which can be either equitably or inequitably distributed. The model acknowledges the nested structure of educational systems and the relationships among various factors at different levels. Specifically, the model refers to observable instructional behaviors of teachers in the classroom and includes eight instructional quality dimensions: orientation, structuring, questioning, teaching-modelling, application, time management, creating a learning environment, and classroom assessment (Creemers & Kyriakides, 2013). The research questions that guide the study are:

1. To what extent does student perceived instructional quality and math achievement relate?
2. Does classroom level student perceived instructional quality have an effect on the relationship between student SES and math achievement?
3. To what extend does student level student perceived instructional quality mediates the relationship between student SES and math achievement?

The study uses cross-sectional secondary questionnaire data, to examine the relationship of SES and students perceived instructional quality with their math achievement. Particularly, it used the Swedish grade 8 data from the TIMSS 2019 cycle with a sample size of N=3996 Swedish students. Teacher instructional quality was measured using questionnaire indicators, such as ‘My teacher is good at explaining mathematics’, ‘My teacher has clear answers to my questions’, ‘My teacher links new lessons to what I already know’ etc. These items were measured on a 4-point Likert scale ranging from “agree a lot” to “disagree a lot”. For measuring student SES, information on the number of books at home and students’ responses regarding their father’s and their mother’s education was used. The number of books at home variable has been identified in several studies to be highly correlated with TIMSS achievement (e.g. Wiberg, 2019). A measure of student mathematics achievement, represented by five plausible values for each student’s math performance on a continuous scale provided by the IEA, was utilized in the analysis through a multiple imputation technique. The method of confirmatory analysis was used to test whether the data fit the measurement models, and then there were built structural models based on an extensive literature review. Multilevel structural equation modelling techniques are employed in the study, as educational systems have an inherently multi-layered structure. Students are nested within classrooms, classrooms within schools, and the schools collectively form a national educational system. When individuals are clustered within natural occuring units (e.g., classrooms, schools, etc.), they share unique components that can affect their school performance. Therefore, multilevel models are essential for decomposing variance into its originating levels (Hox, 2002). The data analyses, which was conducted in SPSS 29 and Mplus 8, incorporated student weights, cluster, and the robust maximum likelihood estimator (MLR), while the model fit was assessed using both local and global fit indices.

The preliminary analyses have resulted in well-fitting measurement models for students’ SES and student perceived teachers’ instructional quality latent constructs. The structural models examining the direct and indirect effects of student perceived teachers’ instructional quality on math achievement resulted in an overall good model fit. Model results confirmed that both SES and student perceived instructional quality at student and classroom level significantly relate with math achievement, consistent with prior research. Also, it was found that there is a significant indirect effect of students’ SES to their math achievement through teachers’ instructional quality at the individual level. Further, it was tested the interaction effect of teachers’ instructional quality in a multilevel model. A random slope on the relation between SES and math achievement was specified and teachers’ instructional quality at classroom level was found to have a significant interaction effect on this relationship. While this study centers on teachers’ instruction quality and the connection between student SES and math achievement in Sweden, its results hold significance beyond the Swedish context. Concerns about educational equity and the importance of promoting effective teaching quality are prevalent across every democratic educational system. There is a global movement towards prioritizing equity in education (OECD, 2018), with a consistent emphasis on schooling as a key ‘equalizer’ among individuals of diverse backgrounds, crucial for countries adopting a preventative approach to economic inequality (Hanushek & Woessmann, 2015). Research on how teachers’ instruction quality influences the relationship of student socioeconomic background and academic performance sheds light on the on the pivotal role of teachers in addressing equity issues. Thus, further research is needed to examine how effective teaching contributes in fulfilling schools’ compensatory mission, mitigating the strong correlation between SES and achievement in Sweden and beyond.

Bergem, O. K., Nilsen, T., & Scherer, R. (2016). 7 Undervisningskvalitet i matematikk [7 Teaching quality in mathematics]. In Vi kan lykkes i realfag: Resultater og analyser fra TIMSS 2015, [We can succeed in science: Results and analyzes from TIMSS 2015] (pp. 120-136). Oslo: Universitetsforlaget. Blömeke, S., Olsen, R. V. & Suhl, U. (2016). Relation of Student Achievement to the Quality of Their Teachers and Instructional Quality. In T. Nilsen & J. E. Gustafsson (Eds.), Teacher Quality, Instructional Quality and Student Outcomes (pp. 21-50). Springer. Creemers, B., & Kyriakides, L. (2013). Using the Dynamic Model of Educational Effectiveness to Identify Stages of Effective Teaching: An Introduction to the Special Issue. The Journal of Classroom Interaction, 48(2), 4-10. Darling-Hammond, L. (2014). Strengthening teacher preparation: the holy grail of teacher education. Peabody Journal of Education, 89, 547–561. Ferguson, R.F. (2012). Can student surveys measure teaching quality? Phi Delta Kappa, 94(3), 24–28. Gustafsson, J. E., Nilsen, T., & Hansen, K. Y. (2018). School characteristics moderating the relation between student socio-economic status and mathematics achievement in grade 8. Evidence from 50 countries in TIMSS 2011. Studies in Educational Evaluation, 57, 16-30. Hanushek, E. A., & Woessmann, L. (2015). The knowledge capital of nations: education and the economics of growth. Cambridge: MIT Press. Hox, J. (2002). Multilevel analysis : Techniques and applications. Mahwah, N.J.: Lawrence Erlbaum. Kelcey, B., Hill, H. C., & Chin, M. J. (2019). Teacher mathematical knowledge, instructional quality, and student outcomes: a multilevel quantile mediation analysis. School Effectiveness and School Improvement, 30(4), 398-431. Myrberg, E. & Rosén, M. (2009) Direct and indirect effects of parents´ education on reading achievement among third graders in Sweden. British Journal of Educational Psychology 79, no. 4, pp. 695-711. OECD. (2018). Equity in education: breaking down barriers to social mobility. OECD publishing: Paris. Sirin, S. R. (2005). Socioeconomic status and academic achievement: A meta-analytic review of research. Review of Educational Research, 75(3), 417–453. Wiberg, M. (2019). The relationship between TIMSS mathematics achievements, grades and national test scores. Education Inquiry, 10(4), 328–343. Woessmann, L. (2008). Efficiency and equity of European education and training policies. International Tax and Public Finance, 15, 199-230. Yang Hansen, K., & Gustafsson, J.-E. (2019). Identifying the key source of deteriorating educational equity in Sweden between 1998 and 2014 International journal of educational research, 93, 79-90.