A 2008 study of 24 leading economies by the Organization of Economic Cooperation and Development (OECD) concludes that, "Taxation is most progressively distributed in the United States, probably reflecting the greater role played there by refundable tax credits, such as the Earned Income Tax Credit and the Child Tax Credit. . . . Taxes tend to be least progressive in the Nordic countries (notably, Sweden), France and Switzerland."

The OECD study—titled "Growing Unequal?"—also found that the ratio of taxes paid to income received by the top 10% was by far the highest in the U.S., at 1.35, compared to 1.1 for France, 1.07 for Germany, 1.01 for Japan and 1.0 for Sweden (i.e., the top decile's share of Swedish taxes is the same as their share of income).

A second fatal flaw is that the large share of income reported by the upper 1% is largely a consequence of lower tax rates. In a 2010 paper on top incomes co-authored with Anthony Atkinson of Nuffield College, Messrs. Piketty and Saez note that "higher top marginal tax rates can reduce top reported earnings." They say "all studies" agree that higher "top marginal tax rates do seem to negatively affect top income shares."

I am hesitant, but willing, to accept this narrative. I wonder what someone versed in these matters would have to say about the study referenced.