Depended on the recent datasets, the author argued that the income inequality between the nations is reducing because of the industrialization of the late developing countries. The explanations of the concepts and measurements are clear and cut in this book. Based on the Penn World Table and World Bank PPP, the between-nation Gini, MLD, and Theil indexes were reducing from 1960 to 1998 overtime.
The empirical issue here are the methods of weighted: PPP and population. If the data is weighted by PPP and population, the income inequality is declining. This is because the greatest nations such as China and India performed better than the other small poor nations. Thus, weighted data by population changed the results. Notice that part of the author's evidences took from Maddison's historical estimation of global GDPs. Finally, the author also suggested that the national income inequality is slightly enlarging during 1980-90s....Continua