A paler shade of light?
Are claims made for energy-efficient lightbulbs exaggerated? And a rare interview with one of the greatest mathematicians.

Blowing cold, then hot
New research on the coming decade's climate is contradictory. Why is it more difficult to predict the climate in 2020 than in 2050?

Junk maths
Spurious formulae are used by PR firms to get their clients' products mentioned in the media. Is it harmless fun or maths vandalism?

Understanding rape statistics
The conviction rate for rape in England and Wales - at 6.5 per cent - is notoriously low. But how much does this statistic really tell you?

Fluconomics 2
How reliable are the data being collected on swine flu? Tim Harford speaks to the Chief Medical Officer, Sir Liam Donaldson to find out.