Once the facts have been established as best they can, then comes the decision to act. And in economic policy, as with other policy, all actions have side effects and unintended consequences. There are situations in which even the best analysis does not provide enough certainty to render making a decision easy; it is often tempting not to make a decision at all.
In Australia’s case the ratio of prices to income on a national basis has been apparently at a higher mean level – about 4 to 4½ – for about a decade now. The second support for the claim that dwelling prices are overvalued is the observation that they seem high in comparison with other countries.