Person:
Kraay, Aart
Author Name Variants
Fields of Specialization
Macroeconomics,
Debt management,
Economic growth,
Inequality and shared prosperity
Degrees
Departments
Development Research Group, The World Bank
Externally Hosted Work
Contact Information
Last updated
January 31, 2023
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.
Publication Search Results
1 - 10 of 10
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Publication
Growth Still Is Good for the Poor
(World Bank, Washington, DC, 2013-08)Incomes in the poorest two quintiles on average increase at the same rate as overall average incomes. This is because, in a global dataset spanning 118 countries over the past four decades, changes in the share of income of the poorest quintiles are generally small and uncorrelated with changes in average income. The variation in changes in quintile shares is also small relative to the variation in growth in average incomes, implying that the latter accounts for most of the variation in income growth in the poorest quintiles. These findings hold across most regions and time periods and when conditioning on a variety of country-level factors that may matter for growth and inequality changes. This evidence confirms the central importance of economic growth for poverty reduction and illustrates the difficulty of identifying specific macroeconomic policies that are significantly associated with the relative growth rates of those in the poorest quintiles. -
Publication
Do Poverty Traps Exist?
(World Bank, Washington, DC, 2014-04)This paper reviews the empirical evidence on the existence of poverty traps, understood as self-reinforcing mechanisms through which poor individuals or countries remain poor. Poverty traps have captured the interest of many development policy makers, because poverty traps provide a theoretically coherent explanation for persistent poverty. They also suggest that temporary policy interventions may have long-term effects on poverty. However, a review of the reduced-form empirical evidence suggests that truly stagnant incomes of the sort predicted by standard models of poverty traps are in fact quite rare. Moreover, the empirical evidence regarding several canonical mechanisms underlying models of poverty traps is mixed. -
Publication
Growth is Good for the Poor
(World Bank, Washington, DC, 2001-04)When average income rises, the average incomes of the poorest fifth of society rise proportionately. This is a consequence of the strong empirical regularity that the share of income accruing to the bottom quintile does not vary systematically with average income. The authors document this empirical regularity in a sample of 92 countries spanning the past four decades and show that it holds across regions, periods, income levels, and growth rates. The authors next ask whether the factors that explain cross-country differences in the growth rates of average incomes have differential effects on the poorest fifth of society. They find that several determinants of growth--such as good rule of law, opennness to international trade, and developed financial markets--have little systematic effect on the share of income that accrues to the bottom quintile. Consequently, these factors benefit the poorest fifth of society as much as everyone else. Thee is some weak evidence that stabilization from high inflation and reductions in the overall size of government not only increase growth but also increase the income share of the poorest fifth in society. Finally, the authors examine several factors commonly thought to disproportionately benefit the poorest in society, but find little evidence of their effects. The absence of robust findings emphasizes that relatively little is known about the broad forces that account for the cross-country and intertemporal variation in the share of income accruing to the poorest fifth of society. -
Publication
Growth, Inequality, and Social Welfare : Cross-Country Evidence
(World Bank, Washington, DC, 2014-04)Social welfare functions that assign weights to individuals based on their income levels can be used to document the relative importance of growth and inequality changes for changes in social welfare. In a large panel of industrial and developing countries over the past 40 years, most of the cross-country and over-time variation in changes in social welfare is due to changes in average incomes. In contrast, the changes in inequality observed during this period are on average much smaller than changes in average incomes, are uncorrelated with changes in average incomes, and have contributed relatively little to changes in social welfare. -
Publication
Does IDA Engage in Defensive Lending?
(World Bank, Washington, DC, 2007-08)Multilateral development banks are frequently accused of "defensive lending," the practice of extending new loans purely in order to ensure that existing loans are repaid. This paper empirically examine this hypothesis using data on lending by and repayments to the International Development Association (IDA), which is the largest provider of concessional development loans to low-income countries. The authors argue that key institutional features of IDA both (i) potentially create incentives for defensive lending, and (ii) enable particularly sharp tests of the defensive lending hypothesis. The authors find that there is a surprisingly robust partial correlation between disbursements on new IDA loans and repayments on existing loans. However, a closer look at the evidence suggests that defensive lending is unlikely to be a major explanation for this partial correlation. -
Publication
Instrumental Variables Regressions with Honestly Uncertain Exclusion Restrictions
(World Bank, Washington, DC, 2008-05)The validity of instrumental variables (IV) regression models depends crucially on fundamentally untestable exclusion restrictions. Typically exclusion restrictions are assumed to hold exactly in the relevant population, yet in many empirical applications there are reasonable prior grounds to doubt their literal truth. In this paper I show how to incorporate prior uncertainty about the validity of the exclusion restriction into linear IV models, and explore the consequences for inference. In particular I provide a mapping from prior uncertainty about the exclusion restriction into increased uncertainty about parameters of interest. Moderate prior uncertainty about exclusion restrictions can lead to a substantial loss of precision in estimates of structural parameters. This loss of precision is relatively more important in situations where IV estimates appear to be more precise, for example in larger samples or with stronger instruments. The author illustrates these points using several prominent recent empirical papers that use linear IV models. -
Publication
Weak Instruments in Growth Regressions: Implications for Recent Cross-Country Evidence on Inequality and Growth
(World Health Organization, 2015-11)This paper revisits four recent cross-country empirical studies on the effects of inequality on growth. All four studies report strongly significant negative effects, using the popular system generalized method of moments estimator that is frequently used in cross-country growth empirics. This paper shows that the internal instruments relied on by this estimator in these inequality-and-growth regressions are weak, and that weak instrument-consistent confidence sets for the effect of inequality on growth include a wide range of positive and negative values. This suggests that strong conclusions about the effect of inequality on growth— in either direction—cannot be drawn from these studies. This paper also systematically explores a wide range of alternative sets of internal instruments, and finds that problems of weak instruments are pervasive across these alternatives. More generally, the paper illustrates the importance of documenting instrument strength, basing inferences on procedures that are robust to weak instruments, and considering alternative instrument sets when using the system generalized method of moments estimator for cross-country growth empirics. -
Publication
Toward Successful Development Policies: Insights from Research in Development Economics
(World Bank, Washington, DC, 2020-01)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. -
Publication
Can Disaggregated Indicators Identify Governance Reform Priorities?
( 2010-03-01)Many highly-disaggregated cross-country indicators of institutional quality and the business environment have been developed in recent years. The promise of these indicators is that they can be used to identify specific reform priorities that policymakers and aid donors can target in their efforts to improve institutional and regulatory quality outcomes. Doing so however requires evidence on the partial effects of these many very detailed variables on outcomes of interest, for example, investor perceptions of corruption or the quality of the regulatory environment. In this paper we use Bayesian Model Averaging (BMA) to systematically document the partial correlations between disaggregated indicators and several closely-related outcome variables of interest using two leading datasets: the Global Integrity Index and the Doing Business indicators. We find major instability across outcomes and across levels of disaggregation in the set of indicators identified by BMA as important determinants of outcomes. Disaggregated indicators that are important determinants of one outcome are on average not important determinants of other very similar outcomes. And for a given outcome variable, indicators that are important at one level of disaggregation are on average not important at other levels of disaggregation. These findings illustrate the difficulties in using highly-disaggregated indicators to identify reform priorities. -
Publication
Good Countries or Good Projects? Macro and Micro Correlates of World Bank Project Performance
(World Bank, Washington, DC, 2011-05-01)The authors use data from more than 6,000 World Bank projects evaluated between 1983 and 2009 to investigate macro and micro correlates of project outcomes. They find that country-level "macro" measures of the quality of policies and institutions are very strongly correlated with project outcomes, confirming the importance of country-level performance for the effective use of aid resources. However, a striking feature of the data is that the success of individual development projects varies much more within countries than it does between countries. The authors assemble a large set of project-level "micro" correlates of project outcomes in an effort to explain some of this within-country variation. They find that measures of project size, the extent of project supervision, and evaluation lags are all significantly correlated with project outcomes, as are early-warning indicators that flag problematic projects during the implementation stage. They also find that measures of World Bank project task manager quality matter significantly for the ultimate outcome of projects. They discuss the implications of these findings for donor policies aimed at aid effectiveness.