Trends in Intercountry Income Inequality

这是一项关于国家间收入不平等的研究。各国公民的平均收入相差很大，在世界范围内相差约100倍，这种国家间的不平等是世界收入不平等的主要组成部分，比国家内部的不平等要重要得多。这项研究有三个相关的目标。首先，它将根据两种国民收入衡量标准（一种基于汇率，另一种基于购买力平价）和三种不平等衡量标准（基尼系数、泰尔指数和方差平方系数）构建本世纪中叶以来国家间不平等的趋势。其次，它将把国家间不平等的趋势分解为收入比例变化的部分和各国在世界人口中所占份额变化的部分。第三，它将每隔五年在每个测量点估计每个国家对国家间总不平等的贡献。这项研究将使人们有可能确定随着时间的推移，对国家间不平等的贡献增加或减少的国家的特征。因此，该数据集将为定量科学文献提供基础，研究世界不平等的主要组成部分——国家之间的不平等——变化的根本原因。

This is a study of intercountry income inequality. Nations vary greatly in the average incomes of their citizens, by a factor of about 100 worldwide, and this intercountry inequality is the major component of world income inequality, significantly more important than inequality within nations. This study has three related objectives. First, it will construct trends in intercountry inequality since mid-century based on two measures of national income (one based on exchange rates, the other based on purchasing power parity) and on three measures of inequality (the Gini coefficient, Theil's index, and the squared coefficient of variation). Second, it will decompose trends in intercountry inequality into the part due to changing income ratios and the part due to nations' changing shares of the world population. Third, it will estimate each nation's contribution to total intercountry inequality at each measurement point at five-year intervals. %%% This research will make it possible to determine the characteristics of nations that have increased or decreased their contribution to intercountry inequality over time. Thus this dataset will provide the foundation for a quantitative scientific literature on the underlying causes of change in what is the major component of world inequality: inequality between nations.