On the Decomposition of the Gini Coefficient: an Exact Approach, with an Illustration Using Cameroonian Data

Decomposing inequality indices across household groups or income sources is useful in estimating the contribution of each component to total inequality. This can help policy makers draw efficient policies to reduce disparities in the distribution of incomes using targeting tools. Decomposing relative inequality indices, such as the Gini coefficient, is not a simple procedure since, in many cases, the functional form of inequality indices is not additively separable in incomes. More importantly, for some of the indices on which this decomposition can be performed, the interpretation of the decomposition components is often not well founded. In this paper, we use the Shapley value as well as analytical approaches to perform the decomposition of the Gini coefficient and generalize it, in some cases, to the decomposition of other inequality indices. For the analytical approach, our aim is to extend the same interpretation, attributed to the Gini coefficient, to that of the contribution components.Equity, Inequality, Decomposition, Shapley value

Social Classes, Inequality and Redistributive Policies in Canada

The social performance of fiscal redistributive mechanisms in Canada continues to receive a growing interest from politicians and research scientists. The aim of this paper is to assess the evolution of social classes in Canada and to check whether the market and governmental redistribution factors have affected their evolution during the last decade. We focus on the dynamic of inequality, polarization and progressivity of the fiscal system. The results of this study confirm the effectiveness of governmental redistributive mechanism to decrease inequality and polarization significantly and to maintain the middle social class at the detriment of the poorest one. The other evidence concerns the chronic increase in population share and wellbeing of the rich class. Finally, the progressivity of fiscal sytem has registered a significant increase during the last few years.Social classes, poverty, inequality, redistribution

The Hybrid Multidimensional Index of Inequality

In this paper, we propose a new multidimensional inequality index that satisfies a fundamental set of desired properties. We discuss the case where the social evaluation function of welfare depends simultaneously on unidimensional and multidimensional forms of inequality. We show how this mixed social norm interferes with the most popular axioms conceived specifically for multidimensional indices of inequality. Illustrations of the proposed developments are made using the Cameroonian household surveys, conducted in 2001. It is shown that multidimensional inequality is more pronounced in the Cameroonian semi-urban and rural areas whereas the monetary inequality is more pronounced in urban area.Multidimensional inequality, social welfare, human development

Poverty, Inequality and Stochastic Dominance, Theory and Practice: The Case of Burkina Faso

In this paper we provide a set of rules that can be used to check poverty or inequality dominance using discrete data. Existing theoretical rules assume continuity in incomes or in percentiles of the population. In reality, with the usual household surveys, this continuity does not exist. However, such a discontinuity can be exploited to test for stochastic dominance. This paper also proposes stochastic dominance conditions that check for the statistical robustness of the inferred rankings. The methodology of this paper is illustrated using Burkina Faso's household surveys for the years of 1994 and 1998.Stochastic Dominance, Poverty, Inequality

On the Decomposition of Polarization Indices: Illustrations with Chinese and Nigerian Household Surveys

This paper explores the link between polarization and inequality and proposes some analytical methods to decompose the Duclos, Esteban, and Ray (2004) polarization index by population groups or income sources. In some cases, the decomposition methods were extend to the Esteban and Ray (1994) one. The main aim of these decomposition methods is to extend the interpretation derived from polarization indices to that of contribution components. Results drawn from Chinese data conclude that even if inequality has increased sharply during the last two decades, the pure polarization component was remained constant or even decreased on average. On the other hand, results from the 2004 Nigerian survey conclude that the population is spatially polarized, and this, based on geo-ecological zones. Furthermore, the two income sources, namely, Employment income and Non farm business income, significantly contribute to total polarization.Polarization, Equity, Inequality, Decomposition

Poverty, Inequality and Stochastic Dominance, Theory and Practice: Illustration with Burkina Faso Surveys

In this paper we provide a set of rules that can be used to check poverty or inequality dominance using discrete data. Existing theoretical rules assumes continuity in incomes or in percentiles of population. In reality, with the form of household surveys, this continuity does not exist. However, the said discontinuity can be exploited in testing the stochastic dominance. Moreover, in this paper, we proprose the stochastic dominance conditions that take into account the statistical robustness in testing the stochastic dominance. Findings of this paper are illustrated using the Burkina Faso's household surveys for the years of 1994 and 1998.Stochastic Dominance, Poverty, Inequality

Expected Poverty Changes with Economic Growth and Redistribution

This paper focusses on the theoretical and computational framework in order to estimate the impact of economic growth or that of the change in inequality on poverty. During the last few years, there was a growing interest to perform such estimations and to anticipate the implication of some strategic policies, that can be adopted to meet the Millennium Development Goal (MDG, henceforth), that is to cut poverty by half. As is illustrated in this paper, estimated poverty changes may be less precise or even wrong. Precisely, this bad estimation occurs when the distributive changes are non-marginal, whereas the used approach is based on the assumption of marginal changes. In an other case, and where the estimation is implicitly based on a parameterized model of the income distribution, results may be less precise when the predicted distribution cannot reproduce perfectly that derived with the sample. In this study, by using some popular methods, we have used some household surveys of the African countries, as well as, fictive data to show the error size that can occur. Further, we propose a new numerical method to allow to estimate accurately the impact of distributive changes on poverty

Poverty and Inequality Components: a Micro Framework

This paper explores the link between poverty and inequality through an analysis of the poverty impact of changes in income-component inequality and in between -an within- group inequality. This can help shed light on the theoretical and empirical linkages between poverty, growth and inequality. It might also help design policies to improve both equity and welfare. The tools are illustrated using the recent 2004 Nigerian national household survey. The analytical derived linkages are supported by the empirical illustration, and interesting insights also emerge from the empirical analysis. One such insight is that both the sign and the size of the elasticities can be quite sensitive to the choice of measurement assumptions (such as the choice of inequality and poverty aversion parameters, and that of the poverty line). The elasticities are also very much distributive-sensitive and dependent on the type of inequality-changing processes taking place. This also suggests that the response of poverty to growth can also be expected to be significantly context specific.Poverty, inequality, poverty elasticities, redistribution

Poverty and Inequality Nexus: Illustrations with Nigerian Data

The main aim of this paper is to explore the link between poverty and inequality. In developing countries, there is a general consensus that high inequality can dampen significantly the impact of economic performance on poverty. In this paper, we propose a new theoretical framework that links poverty and inequality. We also show between and within group inequalities, as well as inequality in income sources, can contribute to total poverty. The methodology of the paper is illustrated using the 2004 Nigerian national living standard survey.Poverty, Inequality

An Atkinson-Gini Family of Social Evaluation Functions

We propose a class of social evaluation functions and of inequality indices which merge the useful features of the family of Atkinson (1970) and of S-Gini (Donaldson and Weymark (1980, 1983), Yitzhaki (1983) and Kakwani (1980)) indices. These social evaluation functions can be interpreted as average utility corrected for relative deprivation in individual welfare. They can also be understood as averages of altruistic welfare in the population, and have a simple and useful graphical interpretation.Social evaluation functions, Inequality indices, Relative deprivation, Altruism