Opportunity to learn: A comparison of analytical approaches and relations to student achievement

• Opportunity to learn (OTL) reflects access to taught content and affects equity. • Compared four OTL models using TIMSS 2015 and 2019 data from Norway and Sweden. • Model performance varied by country, subject, and assessment cycle. • Latent variable model showed the most consistent links to student achievement. • Findings offer guidance on model selection aligned with research or policy goals. Opportunity to learn (OTL), commonly conceptualised as content coverage, plays a pivotal role in shaping student achievement and educational equity. However, the literature lacks comparative analyses of different OTL modelling approaches using the same dataset, which is essential to isolate the effects of model structure from variations caused by context, population, or assessment design. This study addresses that gap using structural equation modeling to compare four widely used analytical approaches of OTL— composite, domain-general, domain-specific, and latent variable models —using Grade 4 mathematics and science data from the Trends in International Mathematics and Science Study (TIMSS) 2015 and 2019 in Norway and Sweden. Results show that model performance varied significantly across countries, subjects, and assessment cycles. The composite approach provided stable but limited insights. The domain-general and domain-specific models offered more targeted but inconsistent findings. The domain-specific model showed strong alignment between content coverage and achievement in specific subdomains, especially in Norwegian mathematics and Swedish science. The latent variable model yielded the most robust and consistent results across countries and subjects, demonstrating its utility in capturing shared variance across domains and reducing measurement error. Mathematics showed more stable OTL–achievement relationships than science, and Norway exhibited stronger model performance than Sweden, particularly in 2015. The findings highlight how OTL is operationalised significantly affects explanatory power and interpretability. This study offers empirical and methodological insights into OTL research, guiding researchers on model selection. It also informs policymakers how different models may serve distinct purposes, such as monitoring trends or designing targeted curriculum and instructional interventions.