均等指数和两极化指数建立与比较

在基尼系数衡量收入差距存在一定缺陷和我国收入两极化概念不清楚的情况下,本文重点对基尼系数与两极分化的涵义进行了剖析,指出了两个概念的本质与它们之间的联系、区别。对以后的收入差距测量有一定的指导意义。基尼系数反映了所有个体偏离总体的程度,两极化指数反映二大组之间差异情况。在前人测量收入差距方法基础上构造两极分化指数I。结合中国和部分其它国家的数据,测量了三个指数并进行了比较分析,结果表明:三个指数高度相关,在一般情况下均等指数、基尼系数和两极分化指数都能大致反映收入差距情况。对组间、组内差距处理方法不同是基尼系数(均等指数)与两极分化指数最根本的区别。构造的两极分化指数具有直观、易于理解、意义明确、计算简单等诸多优点。因此在测量收入差距时,倡导优先使用均等指数。在测量只有二等分组构成总体的收入差距时,优先选择两极分化指数。实际研究中,可以根据研究的问题,合理地选择基尼系数,均等指数,两极分化指数从事相关研究。

Creation and Comparison of Income Equal Index and Bi-polarization

Under the condition defects of measuring income gap by Gini coefficient and unclearness of income polarization concept; this paper focuses on the meanings of Gini coefficient polarization,and points out the nature,the link and the difference between Gini coefficient and polarization.It has certain significane to measure the income gap.Gini coefficient reflects the degree of individual’s deviation from the total.The polarization index reflects the differences of two large equal groups.Based on the former income gap measurement method,the paper built new polarization index I and measured urban income gap,rural income gap in China and in come gaps of some foreign countries. The results shows that,the three indexes, equal indes,Gini coefficient and polarization index, are highly correlated.In general,the three indexes can largely reflect the actual situation of the income gap.The basic difference between Gini coefficient(equal index) and polarization is the treatment among groups and within groups.The index I which was built by author is better than Gini coefficient.It is intuitive,easy to understand,and explicit.When we measure the income gap,the author recommends to use the equal index.When measuring the two equal groups income gap,polarization index should beused.