Did 'rock-star' French economist Thomas Piketty get his numbers wrong? His theories about rising inequality and the increasing importance of capital have been the talk of the economic and political worlds this year. And part of their appeal has been the massive amount of data Piketty has brought together to back them. But the Financial Times claims to have found significant problems with Piketty's data on wealth, and says this undermines his claims about rising inequality. Tim Harford examines the FT's claims and Thomas Piketty's response. Plus: is as much land given over to golf courses as housing in England; is racism on the rise in Britain; and should we be concerned that several young men who have died recently were players of the video game Call of Duty?