The focus on the share of top incomes gives a misleading characterization of the key determinants of societal inequality

See The Rise and Fall of General Laws of Capitalism by Daron Acemoglu (MIT economics dept)and James A. Robinson (Harvard government dept). In response to Piketty. Hare are the abstract and conclusion:

"Thomas Pikettyís recent book, Capital in the Twenty First Century, follows in the tradition of the great classical economists, Malthus, Ricardo and Marx, in formulating ìgeneral lawsîto diagnose and predict the dynamics of inequality. We argue that all of these general laws are unhelpful as a guide to understand the past or predict the future, because they ignore the central role of political and economic institutions in shaping the evolution of technology and the distribution of resources in a society. Using the economic and political histories of South Africa and Sweden, we illustrate not only that the focus on the share of top incomes gives a misleading characterization of the key determinants of societal inequality, but also that inequality dynamics are closely linked to institutional factors and their endogenous evolution, much more than the forces emphasized in Pikettyís book, such as the gap between the interest rate and the growth rate."

"Pikettyís ambitious work, fashioning itself after Marxís Capital, has focused a great deal of new attention on inequality. Piketty pro§ers a bold, sweeping theory of inequality applicable to all capitalist economies. Though we believe that the focus on inequality and the ensuing debates are very healthy and constructive, we have argued that Piketty goes wrong for exactly the same reasons that Marx, and before him Malthus and Ricardo, went astray: his approach and general laws ignore both institutions and the áexible and multifaceted nature of technology shaped by institutions. We have further suggested that the history of inequality over 20th century in economies such as South Africa and Sweden shows why the focus on top 1% inequality is unsatisfactory and why any plausible theory of inequality has to include political and economic institutions at the center stage. We have also provided a brief outline of a framework that squarely puts the spotlight on institutions, their nature and evolution in the study of inequality."