Neoclassical models imply convergence of the entire distribution, not just the mean income levels. In this paper, we analyze convergence in income inequality by using the considerably enlarged data bases, from the World Bank (Povcal) and the World Institute for Development Economic Research (WIDER). Convergence in gini indices of inequality is tested across 55 countries. We consider three sample subsets; one for the developing countries, second of the developed countries and third with all countries together. We test for convergence in gini indices over a period of 5, 10, 15, 20 and 25 years. Additionally we use cross-section (OLS), panel (GMM) and a novel OLS estimation methods. Our results uniformly indicate that inequality levels among developing countries converged. Evidence of convergence is weaker among developed countries. Developing countries appear to converge faster than developed countries.

Is income inequality tending to fall in countries with high inequality and to rise in those where inequality is low? Is there a process of convergence toward medium-level inequality?

The combination of stagnant growth and high levels of income inequality renewed the debate about whether a more even distribution of income can spur economic activity. This paper tests for cross-country convergence in income inequality and estimates its impact on economic growth with a heterogeneous panel structural vector autoregression model, which addresses some empirical challenges plaguing the literature. We find that income inequality is converging across countries, and that its impact on economic growth is heterogeneous. In particular, while the median response of real per capita GDP growth to shocks in income inequality is negative and significant, the dispersion around the estimates is large, with at least one fourth of the countries in the sample presenting a positive effect. The results suggest that the negative effect is mainly driven by the Middle East and Central Asia and the Western Hemisphere across regions, and emerging markets across income levels. Finally, we find evidence that improved institutional frameworks can reduce the negative effect of income inequality on growth.

This paper analyzes the extent of income inequality from a global perspective, its drivers, and what to do about it. The drivers of inequality vary widely amongst countries, with some common drivers being the skill premium associated with technical change and globalization, weakening protection for labor, and lack of financial inclusion in developing countries. We find that increasing the income share of the poor and the middle class actually increases growth while a rising income share of the top 20 percent results in lower growth—that is, when the rich get richer, benefits do not trickle down. This suggests that policies need to be country specific but should focus on raising the income share of the poor, and ensuring there is no hollowing out of the middle class. To tackle inequality, financial inclusion is imperative in emerging and developing countries while in advanced economies, policies should focus on raising human capital and skills and making tax systems more progressive.

"The paper presents a nontechnical summary of the current state of debate on the measurement and implications of global inequality (inequality between citizens of the world). It discusses the relationship between globalization and global inequality. And it shows why global inequality matters and proposes a scheme for global redistribution. "--World Bank web site.

Based on stylized evidence showing variation of the Gini coefficient of income inequality across skill cohorts and on the rapid rise in trade in technology-intensive goods, the ripple effects of technology transmission and income inequality are explored in a global Computable General Equilibrium (CGE) framework. An exogenous technology shock transmitted via trade from the United States induces productivity growth in developing regions. This spillover capture-aided by absorptive capability, better governance and institutions, technological symmetry and social acceptance-causes income to increase and income inequality to decline. The conjoined parameters retard growth's inequality-enhancing effect and thus facilitate long-run convergence of inequality between nations.

This monograph presents methods for full comparative distributional analysis based on the relative distribution. This provides a general integrated framework for analysis, a graphical component that simplifies exploratory data analysis and display, a statistically valid basis for the development of hypothesis-driven summary measures, and the potential for decomposition - enabling the examination of complex hypotheses regarding the origins of distributional changes within and between groups. Written for data analysts and those interested in measurement, the text can also serve as a textbook for a course on distributional methods.

Is income inequality tending to fall in countries with high inequality and to rise in those where inequality is low? Is there a process of convergence toward medium-level inequality? Comparing changes in inequality with initial levels, using new data, Ravallion finds that within-country inequality in income or per capita consumption is converging toward medium levels - a Gini index around 40 percent. The finding is robust to allow for serially independent measurement error in inequality data and for short-run dynamics around longer-term trends. However, the convergence process is neither rapid nor certain, and more observations over time are needed to be confident of the pattern. Ravallion offers an approach to modeling the determinants of inequality that may be a starting point for estimating richer models.This paper - a product of Poverty, Development Research Group - is part of a larger effort in the group to better understand what is happening to income inequality within developing countries.