On October 28th Fortescue reversed its long-standing public optimism and announced it would curtail expansion, a huge blow given the importance of scale in efficient mining of iron ore.

ECONOMIST: Fortunes in the mining business come and go faster than ever

Its officials argue that insurers in foreign markets should either be very strong or get out, because of the importance of economies of scale.

ECONOMIST: European insurance

To run simulations, Guillermo Owen of the Naval Postgraduate School in Monterey, California, uses intelligence data from the US Air Force to estimate on a 100-point scale the importance a wanted man attaches to his likes (fishing, say) and priorities (remaining hidden or, at greater risk of discovery, recruiting suicide-bombers).

ECONOMIST: Modelling behaviour