The chief economist of the IMF, then a professor at MIT, Olivier Blanchard claimed in 2000 in his Harry Johnson lecture and his article with Justin Wolfers (Blanchard & Wolfers 2000), that to explain both the rise and cross country heterogeneity in European unemployment since the 1960s, the interaction between shocks and institutions is crucial.
We should, therefore, aim to make sure that the supply of money grows at a constant rate which is consistent with this. The actual rate will depend on the trend in the velocity of circulation, but the important thing is that when we find the right rate, we stick to it.