News that chartered financial analysts are losing faith in market efficiency sounds shocking. A poll of British investment professionals conducted by the CFA Society of the UK this month revealed just over two-thirds believed investors in aggregate failed to behave rationally.

But before we assume the volatility and irrationality of markets over the past two years have undermined "the wisdom of crowds", it is worth taking another look at James Surowiecki's excellent 2004 book of the same name, which endorses mass sagacity over individual expertise in everything from open-source computing to traffic management.