Background Evidence on the relationship between teaching and learning conditions during the COVID-19 pandemic, student performance, and resulting inequalities remains scarce, especially across different countries and education systems. Aims This study investigates whether there are subgroups of countries with similar pandemic-era teaching and learning conditions (RQ1), and whether these conditions help explain changes in student performance (RQ2) and socio-economic performance gaps before and after the pandemic (RQ3), controlling for containment policies and socio-economic status. Sample Data from four PISA cycles (2012, 2015, 2018, 2022) across 47 countries, combined with pandemic policy indicators, were analysed. Methods K -means clustering with silhouette validation was used for RQ1, and double-selection Lasso linear regression for RQ2 and RQ3 to address small sample sizes and predictor intercorrelations. Data were analysed at the country level. Results Three clusters emerged: (1) F amily- Supported Asynchronous Instruction , (2) Accentuated Teacher-Led Synchronous Instruction and (3) Accentuated Instructional Disruption . Countries in Cluster 2 showed higher post-pandemic performance, while the socio-economic gap widened more in Clusters 2 and 3. Differences in socio-economic performance gaps could not be explained by teaching and learning conditions. Conclusions Results demonstrate that favourable socio-economic conditions enabled highly developed countries to implement modern pedagogical approaches and digital technologies in education. The positive outcomes observed in countries within Cluster 2 ( Accentuated Teacher-Led Synchronous Instruction ) suggest that regular teacher-student contact and consistent monitoring of learning played an important role.
Pham et al. (2026) studied this question.