Kraay, Aart

Person:
Kraay, Aart

Development Research Group, The World Bank

Fields of Specialization

Macroeconomics, Debt management, Economic growth, Inequality and shared prosperity

Departments

Development Research Group, The World Bank

Last updated: March 28, 2025

Biography

Aart Kraay is Director of Research in the Development Research Group at the World Bank. He joined the World Bank in 1995 after earning a Ph.D. in economics from Harvard University (1995), and a B.Sc. in economics from the University of Toronto (1990). His research interests include international capital movements, growth and inequality, governance, and the Chinese economy. His research on these topics has been published in scholarly journals such as the Quarterly Journal of Economics, the Review of Economics and Statistics, the Economic Journal, the Journal of Monetary Economics, the Journal of International Economics, and the Journal of the European Economic Association. He is an associate editor of the Journal of Development Economics, and co-editor of the World Bank Economic Review. He has also held visiting positions at the International Monetary Fund and the Sloan School of Management at MIT, and has taught at the School of Advanced International Studies at Johns Hopkins University.

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Now showing 1 - 10 of 67

The Worldwide Governance Indicators: Methodology and 2024 Update
(Washington, DC: World Bank, 2024-11-07) Kaufmann, Daniel; Kraay, Aart
This paper provides an overview of the data sources and aggregation methodology for the Worldwide Governance Indicators (WGI). The WGI report six aggregate governance indicators measuring Voice and Accountability, Political Stability and Absence of Violence/Terrorism, Government Effectiveness, Regulatory Quality, Rule of Law, and Control of Corruption in a sample of 214 economies over the period 1996–2023. The aggregate indicators combine information from 35 different existing data sources, capturing subjective perceptions of the quality of various dimensions of governance reported by experts and survey respondents worldwide. The paper briefly discusses how to use reported margins of error when interpreting cross-country and over-time differences in the aggregate indicators. The paper also updates and extends earlier analysis on three key issues relating to the WGI methodology: (a) the effect of correlated perception errors, (b) the robustness of the aggregate indicators to alternative weighting schemes, and (c) the existence on trends in global averages of governance.
A New Distribution Sensitive Index for Measuring Welfare, Poverty, and Inequality
(Washington, DC: World Bank, 2023-06-22) Kraay, Aart; Lakner, Christoph; Özler, Berk; Decerf, Benoit; Jolliffe, Dean; Sterck, Olivier; Yonzan, Nishant
Simple welfare indices such as mean income are ubiquitous but not distribution sensitive. In contrast, existing distribution sensitive welfare indices are rarely used, often because they are difficult to explain and/or lack intuitive units. This paper proposes a simple new distribution sensitive welfare index with intuitive units: the average factor by which individual incomes must be multiplied to attain a given reference level of income. This new index is subgroup decomposable with population weights and satisfies the three main definitions of distribution sensitivity in the literature. Variants on this index can be used as distribution sensitive poverty measures and as inequality measures, with the same simple intuitive units. The properties of the new index are illustrated using the global distribution of income across individuals between 1990 and 2019, as well as with selected country comparisons. Finally, the index can be used to define the “prosperity gap” as a proposed new measure of “shared prosperity,” one of the twin goals of the World Bank.
Predicting Food Crises
(World Bank, Washington, DC, 2020-09) Spencer, Phoebe; Kraay, Aart; Wang, Dieter; Andree, Bo, Pieter Johannes
Globally, more than 130 million people are estimated to be in food crisis. These humanitarian disasters are associated with severe impacts on livelihoods that can reverse years of development gains. The existing outlooks of crisis-affected populations rely on expert assessment of evidence and are limited in their temporal frequency and ability to look beyond several months. This paper presents a statistical forecasting approach to predict the outbreak of food crises with sufficient lead time for preventive action. Different use cases are explored related to possible alternative targeting policies and the levels at which finance is typically unlocked. The results indicate that, particularly at longer forecasting horizons, the statistical predictions compare favorably to expert-based outlooks. The paper concludes that statistical models demonstrate good ability to detect future outbreaks of food crises and that using statistical forecasting approaches may help increase lead time for action.
The World Bank Human Capital Index: A Guide
(Published by Oxford University Press on behalf of the World Bank, 2019-02) Kraay, Aart
This paper provides a guide to the new World Bank Human Capital Index (HCI), situating its methodology in the context of the development accounting literature. The HCI combines indicators of health and education into a measure of the human capital that a child born today can expect to achieve by her 18th birthday, given the risks of poor education and health that prevail in the country where she lives. The HCI is measured in units of productivity relative to a benchmark of complete education and full health, and ranges from 0 to 1. A value of x on the HCI indicates that a child born today can expect to be only x×100 percent as productive as a future worker as she would be if she enjoyed complete education and full health.
Toward Successful Development Policies: Insights from Research in Development Economics
(World Bank, Washington, DC, 2020-01) Artuc, Erhan; Cull, Robert; Dasgupta, Susmita; Fattal, Roberto; Filmer, Deon; Gine, Xavier; Jacoby, Hanan; Jolliffe, Dean; Kee, Hiau Looi; Klapper, Leora; Kraay, Aart; Loayza, Norman; Mckenzie, David; Ozler, Berk; Rao, Vijayendra; Rijkers, Bob; Schmukler, Sergio L.; Toman, Michael; Wagstaff, Adam; Woolcock, Michael
What major insights have emerged from development economics in the past decade, and how do they matter for the World Bank? This challenging question was recently posed by World Bank Group President David Malpass to the staff of the Development Research Group. This paper assembles a set of 13 short, nontechnical briefing notes prepared in response to this request, summarizing a selection of major insights in development economics in the past decade. The notes synthesize evidence from recent research on how policies should be designed, implemented, and evaluated, and provide illustrations of what works and what does not in selected policy areas.
Methodology for a World Bank Human Capital Index
(World Bank, Washington, DC, 2018-09) Kraay, Aart
This paper describes the methodology for a new World Bank Human Capital Index (HCI). The HCI combines indicators of health and education into a measure of the human capital that a child born today can expect to obtain by her 18th birthday, given the risks of poor education and health that prevail in the country where she lives. The HCI is measured in units of productivity relative to a benchmark of complete education and full health, and ranges from 0 to 1. A value of x on the HCI indicates that a child born today can expect to be only x x100 percent as productive as a future worker as she would be if she enjoyed complete education and full health. The methodology of the HCI is anchored in the extensive literature on development accounting.
A Socioeconomic Disaggregation of the World Bank Human Capital Index
(World Bank, Washington, DC, 2019-09) D'Souza, Ritika; Gatti, Roberta; Kraay, Aart
This paper documents inequality in health and education outcomes by constructing an index of human capital disaggregated by quintiles of socioeconomic status (SES) for a sample 51 mostly low- and middle-income countries. The index measures the expected future human capital of children born today, following the methodology of the World Bank Human Capital Index that was launched in October 2018. Within-country disparities in human capital outcomes across SES quintiles are large, accounting for roughly one-third of the total variation. On average, human capital outcomes increase with income at roughly the same rate across socio-economic groups within countries as they do across countries.
Predicting Conflict
(World Bank, Washington, DC, 2017-05) Celiku, Bledi; Kraay, Aart
This paper studies the performance of alternative prediction models for conflict. The analysis contrasts the performance of conventional approaches based on predicted probabilities generated by binary response regressions and random forests with two unconventional classification algorithms. The unconventional algorithms are calibrated specifically to minimize a prediction loss function penalizing Type 1 and Type 2 errors: (1) an algorithm that selects linear combinations of correlates of conflict to minimize the prediction loss function, and (2) an algorithm that chooses a set of thresholds for the same variables, together with the number of breaches of thresholds that constitute a prediction of conflict, that minimize the prediction loss function. The paper evaluates the predictive power of these approaches in a set of conflict and non-conflict episodes constructed from a large country-year panel of developing countries since 1977, and finds substantial differences in the in-sample and out-of-sample predictive performance of these alternative algorithms. The threshold classifier has the best overall predictive performance, and moreover has advantages in simplicity and transparency that make it well suited for policy-making purposes. The paper explores the implications of these findings for the World Bank's classification of fragile and conflict-affected states.
Approximating Income Distribution Dynamics Using Aggregate Data
(World Bank, Washington, DC, 2017-06) Kraay, Aart; Van der Weide, Roy
This paper proposes a methodology to approximate individual income distribution dynamics using only time series data on aggregate moments of the income distribution. Under the assumption that individual incomes follow a lognormal autoregressive process, this paper shows that the evolution over time of the mean and standard deviation of log income across individuals provides sufficient information to place upper and lower bounds on the degree of mobility in the income distribution. The paper demonstrates that these bounds are reasonably informative, using the U.S. Panel Study of Income Dynamics where the panel structure of the data allows us to compare measures of mobility directly estimated from the micro data with approximations based only on aggregate data. Bounds on mobility are estimated for a large cross-section of countries, using data on aggregate moments of the income distribution available in the World Wealth and Income Database and the World Bank's PovcalNet database. The estimated bounds on mobility imply that conventional anonymous growth rates of the bottom 40 percent (top 10 percent) that do not account for mobility substantially understate (overstate) the expected growth performance of those initially in the bottom 40 percent (top 10 percent).
Governance Matters VIII : Aggregate and Individual Governance Indicators 1996–2008
(2009-06-01) Kaufmann, Daniel; Kraay, Aart; Mastruzzi, Massimo
This paper reports on the 2009 update of the Worldwide Governance Indicators (WGI) research project, covering 212 countries and territories and measuring six dimensions of governance between 1996 and 2008: Voice and Accountability, Political Stability and Absence of Violence/Terrorism, Government Effectiveness, Regulatory Quality, Rule of Law, and Control of Corruption. These aggregate indicators are based on hundreds of specific and disaggregated individual variables measuring various dimensions of governance, taken from 35 data sources provided by 33 different organizations. The data reflect the views on governance of public sector, private sector and NGO experts, as well as thousands of citizen and firm survey respondents worldwide. The authors also explicitly report the margins of error accompanying each country estimate. These reflect the inherent difficulties in measuring governance using any kind of data. They find that even after taking margins of error into account, the WGI permit meaningful cross-country comparisons as well as monitoring progress over time. The aggregate indicators, together with the disaggregated underlying indicators, are available at www.govindicators.org.