世界経済・社会統計 = World development indicators

When average incomes rise, the average incomes of the poorest fifth of society rise proportionately. This holds across regions, periods, income levels, and growth rates. But relatively little is known about the broad forces that account for the variations across countries and across time in the share of income accruing to the poorest fifth. When average incomes rise, 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. Dollar and Kraay 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. Dollar and Kraay 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, openness 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. There 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, Dollar and Kraay 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. This paper - a product of Macroeconomics and Growth, Development Research Group - is part of a larger effort in the group to study growth and poverty reduction. The authors may be contacted at ddollar@worldbank.org or akraay@worldbank.org.

Growth is Good for the Poor

This article presents a new data set on inequality in the distribution of income. The authors explain the criteria they applied in selecting data on Gini coefficients and on individual quintile groups' income shares. Comparison of the new data set with existing compilations reveals that the data assembled here represent an improvement in quality and a significant expansion in coverage, although differences in the definition of the underlying data might still affect intertemporal and international comparability. Based on this new data set, the authors do not find a systematic link between growth and changes in aggregate inequality. They do find a strong positive relationship between growth and reduction of poverty.

A New Data Set Measuring Income Inequality

This article presents a new data set on inequality in the distribution of income. The authors explain the criteria they applied in selecting data on Gini coefficients and on individual quintile groups' income shares. Comparison of the new data set with existing compilations reveals that the data assembled here represent an improvement in quality and a significant expansion in coverage, although differences in the definition of the underlying data might still affect inter temporal and international comparability. Based on this new data set, the authors do not find a systematic link between growth and changes in aggregate inequality. They do find a strong positive relationship between growth and reduction of poverty.

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Financial development disproportionately boosts incomes of the poorest quintile and reduces income inequality. About 40% of the long-run impact of financial development on the income growth of the poorest quintile is the result of reductions in income inequality, while 60% is due to the impact of financial development on aggregate economic growth. Furthermore, financial development is associated with a drop in the fraction of the population living on less than $ 1 a day, a result which holds when conditioning on average growth. These findings emphasize the importance of the financial system for the poor.

Finance, inequality and the poor

A new data set on national poverty lines is combined with new price data and almost 700 household surveys to estimate absolute poverty measures for the developing world We find that 25% of the population lived in poverty in 2005, as judged by what “poverty” typically means in the world's poorest countries This is higher than past estimates Substantial overall progress is still indicated—the corresponding poverty rate was 52% in 1981—but progress was very uneven across regions The trends over time and regional profile are robust to various changes in methodology, though precise counts are more sensitive

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The Developing World is Poorer than We Thought, But No Less Successful in the Fight Against Poverty

Is it true that the poor have lost ground, even as average living standards have risen? No. Poor people typically share in rising average living standards. It has been claimed that in recent times the poor have lost ground, both relatively and absolutely, even as average standards of living were rising. Ravallion and Chen test that claim, using more than 100 household surveys for more than 40 countries. Overall there was a small decrease in poverty incidence in 1987-93, though experiences differed across regions and countries. There was no general tendency for inequality or polarization to increase with growth. Distribution improves as often as it worsens in growing economies, and negative growth often appears to be highly detrimental to distribution. Poor people typically do share in rising average living standards. This holds in all regions. This paper - a product of the Poverty and Human Resources Division, Policy Research Department - is part of a larger effort in the department to monitor progress in reducing poverty in the world.

What Can New Survey Data Tell Us About Recent Changes in Distribution and Poverty

Measuring pro-poor growth

It has been claimed that in recent times the poor have lost ground, both relatively and absolutely, even when average levels of living have risen. This article tests that claim using household surveys for 67 developing and transitional economies over 1981-94. It finds that changes in inequality and polarization were uncorrelated with changes in average living standards. Distribution improved as often as it worsened in growing economies, and negative growth was often more detrimental to distribution than positive growth. Overall, there was a small decrease in absolute poverty, although with diverse experiences across regions and countries. Almost always, poverty fell with growth in average living standards and rose with contraction.

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What can new survey data tell us about recent changes in distribution and poverty

The authors provide new evidence on the extent to which absolute poverty has urbanized in the developing world, and the role that population urbanization has played in overall poverty reduction. They find that one-quarter of the world's consumption poor live in urban areas and that the proportion has been rising over time. By fostering economic growth, urbanization helped reduce absolute poverty in the aggregate but did little for urban poverty. Over 1993-2002, the count of the"$1 a day"poor fell by 150 million in rural areas but rose by 50 million in urban areas. The poor have been urbanizing even more rapidly than the population as a whole. Looking forward, the recent pace of urbanization and current forecasts for urban population growth imply that a majority of the poor will still live in rural areas for many decades to come. There are marked regional differences: Latin America has the most urbanized poverty problem, East Asia has the least; there has been a"ruralization"of poverty in Eastern Europe and Central Asia; in marked contrast to other regions, Africa's urbanization process has not been associated with falling overall poverty.

Shaohua Chen

Papers

The Developing World is Poorer than We Thought, But No Less Successful in the Fight Against Poverty

What Can New Survey Data Tell Us About Recent Changes in Distribution and Poverty

Measuring pro-poor growth

What can new survey data tell us about recent changes in distribution and poverty

New Evidence on the Urbanization of Global Poverty