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  • Originally published 09/20/2013



  • Originally published 01/24/2015


    Liberty and Power

    My previous posts on the data problems in Piketty’s Capital in the Twenty First Century have focused almost entirely on errors contained within his data charts and files. But what happens when one tries to reconstruct those files?To find out, I conducted a simple experiment using Piketty’s Figure 10.5 – the widely cited depiction of wealth inequality in the United States over the past century. I previously deconstructed and critiqued this chart at length, concluding that it is essentially a Frankenstein graph – a clunky assemblage of cherry-picked data points from multiple divergent sources and arranged in an order that seems to confirm Piketty’s historical narrative about a dramatic upturn in inequality since the early 1980s. The purpose was to reconstruct Piketty’s chart using his own source data and techniques, only I would cherry-pick different “representative” numbers than Piketty did from within those sources as needed.The rules:1. I had to use the same data sources that Piketty used in constructing the original. These consist of the estate tax study by Kopczuk & Saez (2004) and SCF studies by Wolff (1994, 2010) and Kennickell (2009, 2011).

  • Originally published 01/06/2015

    Piketty goes cherry-picking for US Wealth Inequality

    Liberty and Power

    One of the main critiques I’ve made of Thomas Piketty’s data, starting on this blog last May and appearing in my newly released paper with Robert Murphy on the subject, concerns his Figure 10.5, purporting to show the trend of wealth inequality in the United States. As I pointed out at the time, this chart suffers from severe distortions starting in the 1970s that come about from Piketty’s unconventional decennial averaging techniques. The result is a downward distortion that gives the appearance of a clear bottom point in 1970, followed by a steady increase in inequality through the present day. Piketty attains this composite trend by essentially cherrypicking from different data sources until he produces the story he wants to depict, even as the trend he claims is far more ambiguous in the raw numbers.Though his citation practices are often opaque, I reconstructed and labeled the source match-up for Figure 10.5 in the following graph so you can see the cherrypicking at play:

  • Originally published 12/29/2014

    An Empirical Critique of Thomas Piketty’s “Capital in the 21st Century”

    Liberty and Power

    I first became aware of Thomas Piketty’s book Capital in the 21st Century last spring, though not from the onset of “Pikettymania” amidst its skyrocketing to the top of the best seller list. Rather, a couple of faculty colleagues brought it to my attention for its data. Knowing of my own research interests in historical tax data from the turn of the century United States, they suggested it as a new and relevant contribution with a fair amount of empirical overlap with what I was doing. I began reading the book as it gained attention for other reasons – mostly its prescriptive recommendation for an intentionally punitive global wealth tax, with rates not unlike the 75% top income tax bracket that had recently been enacted in Piketty’s native France.