Economists are prone to fads, and the latest is machine learning

WHAT is the collective noun for a group of economists? Options include a gloom, a regression or even an assumption. In January, when PhD students jostle for jobs at the annual meeting of the American Economic Association, a "market" might seem the mot juste. Or perhaps, judging by the tendency of those writing economic papers to follow the latest fashion, a "herd" would be best. This year the hot technique is machine learning, using big data; Imran Rasul, an economics professor at University College, London, is expecting to read a pile of papers using this voguish technique.