From Alan Reynolds:
First of all, the Piketty and Saez estimates do not show top 1 percent income shares nearly as high as those of 1916 or 1928 once we use the same measure of total income for both prewar and postwar data.
Second, contrary to Summers, there is no data from Piketty, Saez or anyone else showing that the top 1 percent’s share of wealth “has risen sharply [if at all] over the last generation” – much less exhibited a “return to a pattern that prevailed before World War I.”
Dealing first with income, it is interesting that the first graph in Piketty’s book is about the top 10 percent – not the top 1 percent. Saez likewise writes that “the top decile income share in 2012 is equal to 50.4%, the highest ever since 1917 when the series start.” That is why President Obama said, “The top 10 percent no longer takes in one-third of our [sic] income – it now takes half.” A two-earner New York City family of six with a pretax income of only $110,000 would be in this top 10 percent, and they are certainly not taking “our” income. Regardless whether we examine the Top 10 percent or Top 1 percent, however, it is absolutely dishonest to compare the postwar estimates with prewar estimates.
The Piketty and Saez prewar estimates express top incomes as a share of Personal Income, after subtracting 20% to account for tax avoidance. Postwar estimates, by contrast, express top incomes as a share of only that fraction of income that happens to be reported on individual income tax returns – rather than being unreported, in tax-free savings or assets, or sheltered as retained corporate earnings.
Transfer payments are not counted as income in either series (as though federal cash and benefits were worthless); this distinction is inconsequential for the prewar figures but increasingly important lately. “Total income” as Piketty and Saez define it accounted for just 61.8 percent of personal income in 2012, down from 67 percent in 2000.
Read more at Piketty Problems: Top 1% Shares of Income and Wealth Are Nothing Like 1917- 28 | Cato @ Liberty.