In the wake of the global COVID-19 pandemic, educational disruption has captured the attention of researchers, policymakers, and stakeholders worldwide. However, isolating the precise impact of school and class closures on student achievement remains challenging due to a confluence of complex factors, including economic instability, parental job losses, and altered family dynamics. A groundbreaking study led by Assistant Professor Masato Oikawa at Waseda University in Japan uses a novel approach to disentangle these factors by studying the effects of routine, localized class closures caused by seasonal influenza outbreaks prior to the pandemic. This research offers unprecedented insights into how short-term instructional interruptions differentially affect students across socioeconomic backgrounds.
The study harnesses administrative data from 2015 to 2017, covering all public elementary and middle schools in a metropolitan city within the Tokyo area. By focusing on disruptions caused by influenza, which typically result in class closures lasting an average of two to three days per month, researchers could simulate a natural experiment. This allowed them to examine the direct effects of unscheduled instructional time loss on academic outcomes, separate from the wider societal stresses triggered by the COVID-19 pandemic. Importantly, the team categorized students into low-income and middle-to-high-income brackets based on eligibility for government financial support, enabling a nuanced investigation of socioeconomic disparities.
Utilizing an econometric modeling framework, the researchers evaluated variations in math and language test scores in the academic year following the observed class closures. Their findings reveal a stark and disproportionate impact on students from economically disadvantaged households. Among this group, elementary school boys exhibited the largest decline in mathematics achievement. The negative effect was especially significant for those who initially scored below average at the start of the school year and for closures occurring during the final two months of the academic calendar, underscoring the critical role of both timing and baseline capabilities in educational resilience.
The gender-specific outcomes illuminate an important dimension of educational vulnerability. Boys from low-income homes appeared particularly susceptible, potentially due to compounded factors such as diminished structured learning environments and an increase in detrimental behaviors during closures. Activities like excessive television viewing, heightened engagement with video games, disrupted sleep patterns, and reduced study time emerged as harmful habits exacerbating educational deficits. These lifestyle shifts likely contribute to the observed performance drops, illustrating how beyond absences in formal instruction, environmental and behavioral factors critically mediate academic success.
Remarkably, the study identifies several moderating factors that can buffer against the adverse effects of class closures. Schools with smaller class sizes—defined here as cohorts of 30 students or fewer—and teachers with substantial experience at their current schools were able to mitigate learning loss, particularly among disadvantaged pupils. These findings suggest that the teacher’s familiarity with their student body and the ability to provide more individualized attention can substantially support vulnerable learners amidst disruptions. This insight is vital for designing policies aimed at strengthening school resilience and tailoring teacher deployment strategically.
Assistant Professor Oikawa emphasizes the practical implications of this research for educational policymakers and practitioners. Given that short-term closures, previously considered minor disruptions, can amplify performance disparities, targeted interventions are necessary to curb the widening achievement gap. Schools should proactively prepare online learning materials and implement remedial education programs post-disruption, focusing efforts on classrooms with a high proportion of low-income students. Additionally, parental involvement in maintaining children’s daily routines related to sleep hygiene and limiting screen time emerges as a pivotal factor to sustain learning continuity during school breaks.
This comprehensive analysis also provides a cautionary lens through which to view the effects of pandemic-induced school closures and other public health emergencies. By isolating the impact of localized, influenza-related interruptions, the study underscores the broader challenge of educational inequality exacerbated by systemic shocks. The findings advocate for the development of robust educational infrastructures capable of rapid adaptation, ensuring that all students, regardless of socioeconomic status, maintain equitable access to quality learning opportunities during crises.
The data-driven methodological rigor of the study—a result of collaboration among experts from Waseda University and The University of Tokyo—further strengthens its relevance. Employing detailed administrative records enabled the disentanglement of direct instructional loss from confounding socioeconomic variables. The use of a natural experiment approach based on influenza outbreaks circumvents the complexity inherent in pandemic-related studies, offering a clear window into the causal mechanisms linking class closures to academic outcomes.
Moreover, the differential impacts across subjects and grade levels detected in this research highlight the multifaceted nature of learning disruptions. While mathematics scores in elementary boys were prominently affected, language scores and those of other demographic groups showed varied responses. This heterogeneity suggests the necessity for tailored remedial strategies that address the specific needs of different student populations, rather than a one-size-fits-all solution.
This study contributes significantly to the growing international literature on educational disruptions and social inequality, reinforcing the urgency to integrate equity considerations within education policy. With concrete evidence that short-term closures can erode gains in human capital formation among disadvantaged children, governments and educators are urged to reconsider preparedness protocols. Investing in teacher development, reducing class sizes, and promoting healthy lifestyle habits are actionable pathways to bolster resilience.
In light of these findings, future research directions may include exploring the longitudinal effects of repeated short-term closures and their potential to compound educational deficits. The integration of digital learning platforms and their effectiveness in mitigating instructional loss also warrants comprehensive examination. As educational systems worldwide grapple with uncertainty, the lessons from this Japanese study provide a valuable template to safeguard student achievement and support vulnerable learners.
In summary, the natural experiment conducted by Assistant Professor Masato Oikawa and his colleagues not only quantifies the negative academic impacts of class closures due to influenza but also unveils the socio-behavioral factors intertwined with these outcomes. The study’s implications extend beyond the pandemic epoch, urging a reimagining of educational equity and resilience through data-informed, context-sensitive interventions.
Subject of Research: People
Article Title: Do class closures affect students’ achievements? Heterogeneous effects of students’ socioeconomic backgrounds
News Publication Date: December 1, 2025
Web References:
Journal of the Japanese and International Economies
DOI: 10.1016/j.jjie.2025.101387
References:
Masato Oikawa, Ryuichi Tanaka, Shun-ichiro Bessho, Akira Kawamura, and Haruko Noguchi. Do class closures affect students’ achievements? Heterogeneous effects of students’ socioeconomic backgrounds. Journal of the Japanese and International Economies, Volume 78, December 2025.
Image Credits:
Assistant Professor Masato Oikawa from Waseda University, Japan
Keywords:
Class closures, Education disruption, Socioeconomic inequality, Student achievement, Influenza outbreaks, Educational resilience, Mathematics performance, Educational policy, COVID-19 impact, School closures, Teacher experience, Remedial education
