Changes in income inequality from a global perspective: an overview

Rising income inequality has recently moved into the centre of political and economic debates in line with increasing claims that a global rise in income inequality might have been a root cause of the subprime crisis. This paper provides an extensive overview of world scale developments in relative (i.e. proportional) income inequality to determine if the claims that the latter was high prior to the crisis are substantiated. The results of this study indicate that (i) non-population adjusted inequality between countries (inter-country inequality) increased between 1820 and the late 1990s but then decreased thereafter, while there was a steady decrease after the 1950s when population weights are taken into account; (ii) income inequality between ‘global citizens’ (global inequality) increased significantly between 1820 and 1950, while there was no clear trend thereafter; (iii) contemporary relative income inequality within countries (intra-country inequality) registered a clear upward trend on a global level since the 1980s.