Intercountry Income Inequality: New Analytic Directions

这是一项关于世界收入不平等的研究。 首先，最富裕国家的平均收入是最贫穷国家的30倍，国家间收入-而不是国家内部的不平等-是世界总收入不平等的主要组成部分。该研究项目的前期工作主要集中在为传统的不平等度量（变异系数、基尼系数、泰尔指数和方差）开发一个通用公式，然后将该公式应用于国家间不平等的趋势，以确定基本事实。讨论的问题包括：不平等的程度有多大，是在增加还是在减少，这一趋势是由于各国不同的经济增长还是人口增长，哪些国家对国家间不平等和国家间不平等的变化贡献最大，以及结果是否比传统的不平等措施更有力。该项目的这一新阶段将在新的分析方向上扩展这一研究路线，包括社会福利部分。根据对收入转移的相对福利影响的不同假设，比较国家间不平等的趋势，将确定关于国家间不平等趋势的结论在多大程度上取决于对收入分配的低端和高端给予的相对权重。 这项研究将把社会学研究的科学严谨性提高到一个新的水平，这个社会学研究的重要问题是收入在各国之间的分配是越来越平等还是越来越不平等。

This is a study of world income inequality. It begins from the observations that average incomes in the richest nations are thirty times those in the poorest nations, and that intercountry income -- not inequality within nations -- is the major component of total world income inequality. Previous work in this research program focused on developing a common formula for the conventional inequality measures (the coefficient of variation, the Gini, the Theil index, and the variance of the logarithms) and then applying that formula to trends in intercountry inequality to determine the essential facts. Among the questions addressed were: how large is the inequality, whether it is increasing or decreasing, whether the trend is due to nations' differential economic growth or their differential population growth, what countries contribute most to intercountry inequality and to change in intercountry inequality, and whether results are robust over the conventional inequality measures. This new phase of the project will extend that line of research in new analytic directions, to include a social welfare component. Comparing trends in intercountry inequality based on different assumptions about the relative welfare impact of income transfers will determine the extent to which conclusions about trends in intercountry inequality depend on the relative weight given to the lower and upper ends of the income distribution. This research will bring a new level of scientific rigor to sociological study of the important question of whether income is becoming more equally or less equally distributed across nations.