Economic modelling is like The Wizard of Oz. Behind a impressive facade of power and omnipotence lies an underwhelming array of bizarre assumptions, confused theory, inadequate data, and a desire to please the customer.

Economic modelling, it seems, is loved by everyone. Lobbyists and industry groups love it as it allows them to dress up their self-interest as national interest. Politicians love modelling as it saves them having to explain how their policies will actually work and why we should support them.

And the media love modelling. Who can go past a headline like “Modelling shows carbon tax to cost 24,000 jobs in mining”? Indeed, the media’s love of modelling is the major reason that industry groups and politicians are so keen on it.