Publication: Shrinking Classroom Age Variance Raises Student Achievement : Evidence from Developing Countries
Loading...
Published
2011-01-01
ISSN
Date
2012-03-19
Author(s)
Editor(s)
Abstract
Large classroom variance of student age is prevalent in developing countries, where achievement tends to be low. This paper investigates whether increased classroom age variance adversely affects mathematics and science achievement. Using exogenous variation in the variance of student age in ability-mixing schools, the author finds robust negative effects of classroom age variance on fourth graders' achievement in developing countries. A simulation demonstrates that re-grouping students by age in the sample can improve math and science test scores by roughly 0.1 standard deviations. According to past estimates for the United States, this effect size is similar to that of raising expenditures per student by 26 percent.
Link to Data Set
Citation
“Wang, Liang Choon. 2011. Shrinking Classroom Age Variance Raises Student Achievement : Evidence from Developing Countries. Policy Research working paper ; no. WPS 5527. © World Bank. http://hdl.handle.net/10986/3300 License: CC BY 3.0 IGO.”
Digital Object Identifier
Associated URLs
Associated content
Other publications in this report series
Publication Climate and Social Sustainability in Fragility, Conflict, and Violence Contexts(Washington, DC: World Bank, 2026-01-07)Climate change is widely recognized as a driver of violent conflict, but its broader social effects remain less understood. Ignoring these dimensions risks a vicious cycle where climate policies might undermine socially just adaptation. Evidence is still limited on how climate shocks influence political participation, trust, or migration. This paper helps fill that gap by examining links between climate change, conflict, and social sustainability, with a focus on inclusion, resilience, cohesion, and legitimacy. Using secondary data from 2019–24, the study applies simple correlation-based methods to test three hypotheses on the nature, severity, and composition of these associations. The analysis combines multiple climate impact measures, new conflict classifications, recent social sustainability frameworks, and controls for population and geography. The results reveal strong correlations—not causation—between climate events and contexts of fragility, conflict, and violence. Climate impacts are most pronounced in both national and subnational conflict settings. The study also finds robust links between fragility, conflict, and violence and low levels of social sustainability, reflecting its role as both a driver and consequence of conflict. Some dimensions—such as violent events and insecurity—appear weaker in areas most affected by climate shocks. Two of the hypotheses are supported, and one remains inconclusive.Publication The Macroeconomic Implications of Climate Change Impacts and Adaptation Options(Washington, DC: World Bank, 2025-05-29)Estimating the macroeconomic implications of climate change impacts and adaptation options is a topic of intense research. This paper presents a framework in the World Bank's macrostructural model to assess climate-related damages. This approach has been used in many Country Climate and Development Reports, a World Bank diagnostic that identifies priorities to ensure continued development in spite of climate change and climate policy objectives. The methodology captures a set of impact channels through which climate change affects the economy by (1) connecting a set of biophysical models to the macroeconomic model and (2) exploring a set of development and climate scenarios. The paper summarizes the results for five countries, highlighting the sources and magnitudes of their vulnerability --- with estimated gross domestic product losses in 2050 exceeding 10 percent of gross domestic product in some countries and scenarios, although only a small set of impact channels is included. The paper also presents estimates of the macroeconomic gains from sector-level adaptation interventions, considering their upfront costs and avoided climate impacts and finding significant net gross domestic product gains from adaptation opportunities identified in the Country Climate and Development Reports. Finally, the paper discusses the limits of current modeling approaches, and their complementarity with empirical approaches based on historical data series. The integrated modeling approach proposed in this paper can inform policymakers as they make proactive decisions on climate change adaptation and resilience.Publication Institutional Capacity for Policy Implementation: An Analytical Framework(Washington, DC: World Bank, 2026-01-07)State capacity is an important prerequisite for policy implementation, yet at the country level it is difficult to measure, assess, and reform. This paper proposes a focus on institutional capacity: the ability of public institutions to implement the specific policy mandates for which they are responsible. Based on a review of existing literature, the paper defines the different dimensions that compose institutional capacity and groups them into two cross-cutting categories: organizational dimensions (personnel, financial resources, information systems, and management practices) and governance dimensions (transparency, independence, and accountability). The paper proposes measures for organizational and governance dimensions using existing data, shows intra-institutional variation of these measures within countries, and discusses how new data could be collected for better measurement of these concepts. Finally, the paper illustrates how the framework can be used to diagnose the sources of common problems related to weak policy implementation.Publication South Africa’s Fragmented Cities: The Unequal Burden of Labor Market Frictions(Washington, DC: World Bank, 2026-01-08)Using high-resolution administrative, census, and satellite data, this paper shows that South African cities are characterized by spatial mismatches between where people live and where jobs are located, relative to 20 global peers. Areas within 5 kilometers of commercial centers have 9,300 fewer residents per square kilometer than expected, which is 60 percent below the global median. Poor, dense neighborhoods are most affected. In Johannesburg, a 10-percentile increase in distance from the nearest business hub corresponds to a 3.7-percentile drop in asset wealth (a proxy of household wellbeing) and 4.9-percentile drop in employment. In Cape Town, the declines are 4.0 and 3.7 percentiles, respectively. Employment is 87 percent lower in the poorest decile than the richest in Johannesburg and 61 percent lower in Cape Town. These findings suggest that South Africa’s spatial organization of people and economic activity constrains agglomeration and reinforces inequality. This methodology provides a scalable and standardized data-driven framework to analyze spatial accessibility and agglomeration frictions in complex, data-constrained urban systems.Publication Investment in Emerging and Developing Economies(Washington, DC: World Bank, 2026-01-07)The world faces a pressing challenge to meet key development objectives amid slowing growth and rising macroeconomic and geopolitical risks. With the number of job seekers rising rapidly, infrastructure shortfalls continuing to be large, and climate costs mounting, the case for a significant investment push has never been stronger. Yet the capacity to respond in many emerging markets and developing economies has eroded. Since the global financial crisis, investment growth has slowed to about half its pace in the 2000s, with both public and private investment weakening. Foreign direct investment inflows—a critical source of capital, technology, and managerial know-how—have also fallen sharply and become increasingly concentrated, leaving low-income countries with only a marginal share. The risks of further retrenchment are significant, as trade tensions, policy uncertainty, and elevated debt levels continue to weigh on investment. Reigniting momentum will require ambitious domestic reforms to strengthen institutions, rebuild macro-fiscal stability, and deepen trade and investment integration—the foundations of a supportive business climate. At the same time, international cooperation is indispensable. A renewed commitment to a predictable system of cross-border trade and investment flows, combined with scaled-up financial support and sustained technical assistance, is essential to help emerging markets and developing economies—especially low-income countries and economies in fragile and conflict situations—bridge financing gaps and implement the domestic reforms needed to restore investment as an engine of growth, jobs, and development.
Journal
Journal Volume
Journal Issue
Collections
Related items
Showing items related by metadata.
Publication Unraveling a Secret(World Bank, Washington, DC, 2016-04)This paper seeks to find an empirical explanation of Vietnam's outstanding performance on the Programme for International Student Assessment (PISA) in 2012. Only a few developing countries participate in the assessment. Those who do, with the unique exception of Vietnam, are typically clustered at the lower end of the range of the Programme for International student Assessment scores. The paper compares Vietnam's performance with that of a set of seven developing countries from the 2012 assessment's data set, using a cut-off per capita GDP (in 2010 purchasing power parity dollars) of $10,000. The seven developing countries' average performance lags Vietnam's by more than 100 points. The "Vietnam effect" is difficult to unscramble, but the paper is able to explain about half of the gap between Vietnam and the seven countries. The analysis reveals that Vietnamese students may be approaching their studies with higher diligence and discipline, their parents may have higher expectations, and the parents may be following up with teachers regarding those expectations. The teachers themselves may be working in a more disciplined environment, with tabs being kept on their own performance as teachers. Vietnam may also be benefiting from investments in pre-school education and in school infrastructure that are disproportionately higher when compared with Vietnam's per capita income level.Publication Quality of education in Colombia - Achievements and challenges ahead : analysis of the results of TIMSS 1995-2007(World Bank, 2010-08-06)The main objective of this report is to analyze the effect of time changes and factors associated with student achievement in Colombia in order to foster policies to improve education quality that are grounded in research and the Colombian context. In 2007, Colombia participated for the second time in the Trends in International Mathematics and Science Study (TIMSS), providing a first-time opportunity to analyze the effects of time changes on student achievement over a period (1995-2007) during which a number of education reforms were made. Using the TIMSS 2007 results offers a chance to deepen the study on the factors associated with learning in Colombia and to benchmark Colombia's education system against that of other countries. This effort began during the first phase of the Colombia Programmatic Quality and Relevance of Education Analytic and Advisory Activities (AAA), in which an analysis of Colombia's debut in the 2006 Program for International Student Assessment (PISA), resulted in publication of, 'the quality of education in Colombia: an analysis and options for a policy agenda' report (hereafter, 'PISA report'). The present report builds on this work through an analysis of Colombia's participation in TIMSS 2007 in relation to its performance on TIMSS 1995, and reaffirms the urgent need for improved student learning outcomes in Colombia, further confirming a number of the policy options put forward in the PISA report to inform a future agenda for system design and reform.Publication Nigeria : Anambra Teachers(Washington, DC, 2012-01)Research suggests that teacher quality is the main school-based predictor of student achievement and that several consecutive years of outstanding teaching can offset the learning deficits of disadvantaged students (Hanushek and Rivkin, 2006; Nye et al, 2004; Park and Hannum, 2001; Rivkin et al, 2005; Rockoff, 2004; Sanders, 1998; Sanders and Rivers 1996; and Vignoles et al, 2000). However, it is not yet clear exactly which teacher policies can raise teacher effectiveness (Goldhaber, 2002 and Rivkin et al, 2005). Thus, devising effective policies to improve teaching quality remains a challenge. The eight policy goals includes the following headings: setting clear expectations for teachers; attracting the best into teaching; preparing teachers with useful training and experience; matching teachers' skills with students' needs; leading teachers with strong principals; monitoring teaching and learning; supporting teachers to improve instruction; and motivating teachers to perform.Publication Nigeria : Ekiti Teachers(Washington, DC, 2012-01)Research suggests that teacher quality is the main school-based predictor of student achievement and that several consecutive years of outstanding teaching can offset the learning deficits of disadvantaged students (Hanushek and Rivkin, 2006; Nye et al, 2004; Park and Hannum, 2001; Rivkin et al, 2005; Rockoff, 2004; Sanders, 1998; Sanders and Rivers 1996; and Vignoles et al, 2000). However, it is not yet clear exactly which teacher policies can raise teacher effectiveness (Goldhaber, 2002 and Rivkin et al, 2005). Thus, devising effective policies to improve teaching quality remains a challenge. There is increasing interest across the globe to attract, retain, develop and motivate great teachers. While the World Bank has ample experience in supporting teacher policy reforms in developing countries, until recently there was no systematic effort to offer data and analysis that can provide policy guidance on teacher policies. The focus of the initiative is the design of teacher policies as opposed to their implementation on the ground. A number of complementary activities will be looking at implementation in a sample of countries as this will involve a different methodological approach and will require more financial and human resources.Publication Nigeria : Bauchi Teachers(Washington, DC, 2012-01)Research suggests that teacher quality is the main school-based predictor of student achievement and that several consecutive years of outstanding teaching can offset the learning deficits of disadvantaged students (Hanushek and Rivkin, 2006; Nye et al, 2004; Park and Hannum, 2001; Rivkin et al, 2005; Rockoff, 2004; Sanders, 1998; Sanders and Rivers 1996; and Vignoles et al, 2000). However, it is not yet clear exactly which teacher policies can raise teacher effectiveness (Goldhaber, 2002 and Rivkin et al, 2005). Thus, devising effective policies to improve teaching quality remains a challenge. The eight policy goals includes the following headings: setting clear expectations for teachers; attracting the best into teaching; preparing teachers with useful training and experience; matching teachers' skills with students' needs; leading teachers with strong principals; monitoring teaching and learning; supporting teachers to improve instruction; and motivating teachers to perform.
Users also downloaded
Showing related downloaded files
Publication Digital Progress and Trends Report 2023(Washington, DC: World Bank, 2024-03-05)Digitalization is the transformational opportunity of our time. The digital sector has become a powerhouse of innovation, economic growth, and job creation. Value added in the IT services sector grew at 8 percent annually during 2000–22, nearly twice as fast as the global economy. Employment growth in IT services reached 7 percent annually, six times higher than total employment growth. The diffusion and adoption of digital technologies are just as critical as their invention. Digital uptake has accelerated since the COVID-19 pandemic, with 1.5 billion new internet users added from 2018 to 2022. The share of firms investing in digital solutions around the world has more than doubled from 2020 to 2022. Low-income countries, vulnerable populations, and small firms, however, have been falling behind, while transformative digital innovations such as artificial intelligence (AI) have been accelerating in higher-income countries. Although more than 90 percent of the population in high-income countries was online in 2022, only one in four people in low-income countries used the internet, and the speed of their connection was typically only a small fraction of that in wealthier countries. As businesses in technologically advanced countries integrate generative AI into their products and services, less than half of the businesses in many low- and middle-income countries have an internet connection. The growing digital divide is exacerbating the poverty and productivity gaps between richer and poorer economies. The Digital Progress and Trends Report series will track global digitalization progress and highlight policy trends, debates, and implications for low- and middle-income countries. The series adds to the global efforts to study the progress and trends of digitalization in two main ways: · By compiling, curating, and analyzing data from diverse sources to present a comprehensive picture of digitalization in low- and middle-income countries, including in-depth analyses on understudied topics. · By developing insights on policy opportunities, challenges, and debates and reflecting the perspectives of various stakeholders and the World Bank’s operational experiences. This report, the first in the series, aims to inform evidence-based policy making and motivate action among internal and external audiences and stakeholders. The report will bring global attention to high-performing countries that have valuable experience to share as well as to areas where efforts will need to be redoubled.Publication Using Immunization Coverage Rates for Monitoring Health Sector Performance : Measurement and Interpretation Issues(World Bank, Washington, DC, 2000-08)Immunization against childhood diseases such as diphtheria, pertussis, tetanus, polio and measles is one of the most important means of preventing childhood morbidity and mortality. Despite the low cost of basic childhood immunizations, nearly 3 million children still die each year from vaccine-preventable diseases. Achieving and maintaining high levels of immunization coverage must therefore be a priority for all health systems. In order to monitor progress in achieving this objective, immunization coverage data can serve as an indicator of a health system's capacity to deliver essential services to the most vulnerable members of a population. This note discusses the use of trends in immunization coverage data, and argues that immunization is a health output with a strong impact on child morbidity, child mortality and permanent disability. This note discusses measurement and interpretation issues for coverage data collected through surveys and administrative records.Publication Global Economic Prospects, June 2025(Washington, DC: World Bank, 2025-06-10)The global economy is facing another substantial headwind, emanating largely from an increase in trade tensions and heightened global policy uncertainty. For emerging market and developing economies (EMDEs), the ability to boost job creation and reduce extreme poverty has declined. Key downside risks include a further escalation of trade barriers and continued policy uncertainty. These challenges are exacerbated by subdued foreign direct investment into EMDEs. Global cooperation is needed to restore a more stable international trade environment and scale up support for vulnerable countries grappling with conflict, debt burdens, and climate change. Domestic policy action is also critical to contain inflation risks and strengthen fiscal resilience. To accelerate job creation and long-term growth, structural reforms must focus on raising institutional quality, attracting private investment, and strengthening human capital and labor markets. Countries in fragile and conflict situations face daunting development challenges that will require tailored domestic policy reforms and well-coordinated multilateral support.Publication The Container Port Performance Index 2023(Washington, DC: World Bank, 2024-07-18)The Container Port Performance Index (CPPI) measures the time container ships spend in port, making it an important point of reference for stakeholders in the global economy. These stakeholders include port authorities and operators, national governments, supranational organizations, development agencies, and other public and private players in trade and logistics. The index highlights where vessel time in container ports could be improved. Streamlining these processes would benefit all parties involved, including shipping lines, national governments, and consumers. This fourth edition of the CPPI relies on data from 405 container ports with at least 24 container ship port calls in the calendar year 2023. As in earlier editions of the CPPI, the ranking employs two different methodological approaches: an administrative (technical) approach and a statistical approach (using matrix factorization). Combining these two approaches ensures that the overall ranking of container ports reflects actual port performance as closely as possible while also being statistically robust. The CPPI methodology assesses the sequential steps of a container ship port call. ‘Total port hours’ refers to the total time elapsed from the moment a ship arrives at the port until the vessel leaves the berth after completing its cargo operations. The CPPI uses time as an indicator because time is very important to shipping lines, ports, and the entire logistics chain. However, time, as captured by the CPPI, is not the only way to measure port efficiency, so it does not tell the entire story of a port’s performance. Factors that can influence the time vessels spend in ports can be location-specific and under the port’s control (endogenous) or external and beyond the control of the port (exogenous). The CPPI measures time spent in container ports, strictly based on quantitative data only, which do not reveal the underlying factors or root causes of extended port times. A detailed port-specific diagnostic would be required to assess the contribution of underlying factors to the time a vessel spends in port. A very low ranking or a significant change in ranking may warrant special attention, for which the World Bank generally recommends a detailed diagnostic.Publication Global Economic Prospects, January 2025(Washington, DC: World Bank, 2025-01-16)Global growth is expected to hold steady at 2.7 percent in 2025-26. However, the global economy appears to be settling at a low growth rate that will be insufficient to foster sustained economic development—with the possibility of further headwinds from heightened policy uncertainty and adverse trade policy shifts, geopolitical tensions, persistent inflation, and climate-related natural disasters. Against this backdrop, emerging market and developing economies are set to enter the second quarter of the twenty-first century with per capita incomes on a trajectory that implies substantially slower catch-up toward advanced-economy living standards than they previously experienced. Without course corrections, most low-income countries are unlikely to graduate to middle-income status by the middle of the century. Policy action at both global and national levels is needed to foster a more favorable external environment, enhance macroeconomic stability, reduce structural constraints, address the effects of climate change, and thus accelerate long-term growth and development.