'Cherry picking' Piketty faulted by newspaper for dubious wealth-gap data in best-seller 'Capital'

Thomas Piketty, author of a best-selling book on the widening gap between rich and poor, relied on faulty data that skewed his conclusions, the Financial Times reported.

The mistakes undercut Piketty's argument that wealth inequalities are heading back up to levels last seen before the first world war, wrote Chris Giles, the FT's economics editor.

Data underpinning Piketty's Capital in the Twenty-First Century includes transcription errors, unexplained statistical modifications and "cherry picking" of sources, Giles wrote.

"Some issues concern sourcing and definitional problems," he said. "Some numbers appear simply to be constructed out of thin air."

After correcting for these apparent errors, two of the book's "central findings - that wealth inequality has begun to rise over the past 30 years and that the US obviously has a more unequal distribution of wealth than Europe - no longer seem to hold", according to Giles.

Piketty defended his work in a separate posting on the newspaper's website, saying that he had used a very diverse set of statistics that required him to adjust the data.