Factor decomposition of income inequality change : Japan's regional income disparity from 1955 to 1998

We propose a method for the decomposition of inequality changes based on panel data regression. The method is an efficient way to quantify the contributions of variables to changes of the Theil T index while satisfying the property of uniform addition. We illustrate the method using prefectural data from Japan for the period 1955 to 1998. Japan experienced a diminishing of regional income disparity during the years of high economic growth from 1955 to 1973. After estimating production functions using panel data for prefectures in Japan, we apply the new decomposition approach to identify each production factor’s contributions to the changes of per capita income inequality among prefectures. The decomposition results show that total factor productivity (residual) growth, population change (migration), and public capital stock growth contributed to the diminishing of per capita income disparity.

Economic Reforms and Income Inequality in Urban China

This paper reports the results of an analysis of changes in income inequality, and in its determinants, in urban China since the economic reforms that began in 1978. The intention is to identify new characteristics of economic inequality. It first shows that income differentials acrossand in provinces widened and that their economic rankings were becoming fixed during the period from 1988 to 1995. Second, age was the major factor in inequality in 1988, while education became the important factor in 1995. Third, education significantly contributed to increasing inequality during the period. Fourth, the higher education-level groups had less within-group inequality. These changes reflect the penetration of the market mechanism into China after the reforms. However, this will be problematic without equality of opportunity.