Throughout the 20th Century the developed world saw mortality rates fall but one group who may no longer be benefitting are middle-aged white Americans. This is according to research from the eminent economists Anne Case and Angus Deaton. But the work has been criticised for statistical problems and for not focusing enough on black Americans. Tim Harford attempts to explain what is really going on.

We examine the disturbing rise of fake celebrity social media accounts targeting children. This comes in the wake of a case currently going through the courts in Australia, where a man who allegedly impersonated Justin Bieber online has more than 900 charges of child sex offences against him. We talk to parents of children who have been targeted, and to law enforcement professionals concerned by this growing trend.

The average English-speaker knows about 25,000 words which can be combined into an infinite number of sentences. Many people believe that, whatever language you speak, the words you know have a profound influence on the way you think, though this is a controversial theory among linguists, as Lane Greene explains.

(Photo: Harmonica playing steel workers perched on a girder on the 22nd storey of the Murray Hill building, New York. Credit: General Photographic Agency/Getty Images)