The IMF has released a fairly remarkable piece of self-criticism (pdf) over policy in Greece. On a first read, the report seems to suggest two main failings on the IMF’s part: it failed to acknowledge early on that Greece simply could not repay its debt in full, and it vastly underestimated the economic damage austerity would inflict.
Both errors were, if I may say so, obvious at the time. The troika plan was clearly not realistic — and just about all of us on the Keynesian side were warning, loudly, that multipliers estimated from normal periods with offsetting monetary policy were grossly misleading for fiscal policy under current conditions. All one can say is that the IMF was better than the rest of the troika, with the ECB in particular actually buying in to the fantasy of expansionary austerity.