This study examines the relationship between instructional quality and mathematics achievement across ten European countries using data from the 2012 and 2022 cycles of the Programme for International Student Assessment (PISA). Instructional quality is a crucial determinant of students’ academic performance across subjects, including math- ematics. Effective teaching practices significantly enhance student achievement, underscoring the importance of teacher com- petence and instructional strategies. Recently, the relationship between socioeconomic status (SES), instructional quality, and student mathemat- ics achievement has increasingly gained interest, urged by increased attention on educational equity and quality at large in many countries. Research consistently shows that high-quality instruc- tion benefits high-SES students many than their low-SES peers, exacerbating educational inequalities. This further increases the need to work on SES-related inequalities for achieving equity within educa- tional system

Grounded in the Dynamic Model of Educational Effectiveness (DMEE), this research addresses the following questions:

1. How do students’ perceptions of instructional quality differ across countries and PISA cycles?
2. What are the trends in instructional quality and SES over time?
3. How does instructional quality mediate the relationship between SES and mathematics achievement?

The theoretical framework situates instructional quality as a dynamic construct comprising dimensions such as teacher support, disciplinary climate, and cognitive activation. The DMEE emphasises the adaptability of instructional strategies to meet diverse student needs, particularly in contexts of socioeconomic inequality. By integrating these dimensions with SES, this study aims to provide actionable insights for policymakers and educators to enhance equity and quality in education.

This research adopts a European/international perspective, comparing ten countries—Belgium-Flanders, Denmark, Finland, France, Germany, the Netherlands, Norway, Portugal, Spain, and Sweden. The findings will contribute to understanding how instructional quality can mediate SES-related disparities in mathematics achievement, informing education policies across diverse contexts.

Data were sourced from PISA 2012 and PISA 2022, focusing on mathematics as the primary subject. The analysis includes 75,718 students from 2,964 schools in 2012 and 89,361 students from 3,420 schools in 2022. Instructional quality was operationalised through dimensions such as teacher support, disciplinary climate, and cognitive activation, aligning with the DMEE framework. Socioeconomic status was measured using the Economic, Social, and Cultural Status (ESCS) index, which includes indicators like parental education and home resources. The study employs a multi-step analytical approach: 1. Confirmatory Factor Analysis (CFA): To validate the constructs of instructional quality and ensure measurement invariance across countries and cycles. 2. Trend Analysis: To examine changes in SES and instructional quality dimensions over time. 3. Structural Equation Modelling (SEM): To explore the interrelationships among SES, instructional quality, and mathematics achievement, controlling for country-specific effects. Descriptive statistics and one-way ANOVA were conducted to test mean differences in SES and instructional quality dimensions across cycles. Plausible values of mathematics achievement were analyzed using imputation techniques to ensure robust estimates. SEM was performed using Mplus 8.5. The estimation of achievement plausible values was conducted with the TYPE = IMPUTATION command, which averages across the five and ten datasets to obtain average estimates and proper standard deviations.

Preliminary results indicate that teacher support and disciplinary climate consistently predict higher mathematics achievement across countries and cycles. Cognitive activation, however, exhibits mixed effects, with its sub-dimensions fostering reasoning having positive impacts, while encouraging mathematical thinking sometimes negatively affects low-SES students. Trends in SES show improvements in some countries (e.g., Denmark, Portugal) but declines in others (e.g., Germany, Finland), highlighting the critical role of national policies. Teacher support improved significantly in countries like Germany and Spain but declined in Nordic countries, reflecting variations in education policies and practices. The findings underscore the importance of instructional quality in mitigating SES-related disparities. Dimensions such as teacher support and disciplinary climate can serve as levers for promoting equity, while nuanced approaches to cognitive activation are needed to avoid overburdening low-SES students. These insights inform targeted interventions to enhance instructional quality and support disadvantaged students, contributing to equitable and effective education systems.

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