A further issue is that the literature on the efficacy of macroprudential tools in limiting the buildup of cyclical systemic risks is still at an early stage.
"By 2005 New Zealand's normal short-term interest rates were looking high by OECD standards (though not, despite some media confusion, the highest). The difference in yields was attractive to some investors, and that is one of the factors that contributed to the persistently strong New Zealand dollar. (Another key reason, we should not forget, was the strong terms of trade.)