First, there is still no general agreement on the objective of macroprudential policy - are we concerned about protecting the financial sector from swings in the real economy or protecting the real economy from cycles and swings in the financial sector?
Secondly, we have an idea of what some of the macroprudential instruments should look like, but these are not well developed, and as yet untested in many instances. Furthermore, because the efficacy of these instruments is dependent on the nature and structure of the financial system, their usefulness may differ from country to country and therefore are not necessarily generally applicable.