Lunchtime Must-Read: Jérémie Cohen-Setton: The Piketty Data Controversy

Jérémie Cohen-Setton: The Financial Times Attack on Thomas Piketty: “Matt O’Brien writes that [Chris] Giles identifies…

…simple transcription errors… 1908 instead of 1920…. They’re embarrassing, but they don’t change the big picture…. [Chris] Giles thinks Piketty should average European data by population, not by country…. And Giles isn’t sure why Piketty has put together some of his wealth data—which is sparse, and needs to be adjusted, if not constructed—the way that he has. But these aren’t errors. They’re questions….Ryan Avent writes that while some of the data and adjustments in the spreadsheets lack adequate documentation, Giles does not have the evidence to justify the implication that figures are drawn ‘from thin air’. Data fabrication is a serious charge to make, and I am surprised Mr Giles would allege it without clearer proof. Simon Wren-Lewis writes that the only issue of substance involves trends in the UK wealth income ratio, but of course an article headlined ‘Data sources on UK wealth income ratio differ’ would not have had the same punch. Justin Wolfers writes that while it’s quite natural for a journalist to emphasize the differences between his findings and those of a famous author, the most striking fact is how closely The F.T.’s analysis agrees with Mr. Piketty’s. Their preferred time series for the evolution of wealth inequality are remarkably similar…