Is it fair to say that the question must be if opening the door to QE the question must centre whether you have a programme large enough to achieve what is required but which isn’t too large to disrupt the economy and to stoke too high an inflation rate?
Let me put it extremely simply: for it to be efficient is has to be big. How big is big enough? This has to be an informed decision based on what we know are the transmission channels: is it more a direct impact on interest rates, is it more on the so-called portfolio rebalancing effect, that banks would buy other kinds of assets, etc?