Is it worth it? That’s the question the new federal government should be asking about every marvellous new idea on the nation’s infrastructure wishlist – and backing up the answer with cost-benefit analysis.

Of course, cost-benefit analysis doesn’t capture everything that matters – that’s why experts are constantly refining the method. But while there is certainly room for refinement of how cost-benefit analysis is done, the unfortunate reality is not so much that it’s done imperfectly as that it’s often not done until after the decision to invest has been made – if it’s done at all.