How many economists does it take to set an interest rate? 320 staff toil away in the Bank of England's monetary analysis area. New Zealand's reserve bank manages with an entire staff of under 200. On the other hand, the Bank of England's total headcount of 2,200 is dwarfed by the Bundesbank's 16,000. Clearly, these institutions perform different tasks in different economies. However, with such a huge divergence, it is clearly worth asking: how efficient are central banks?

As the massed ranks