New Keynesian NK adjustment to our basic RBCs

SWL " The New Keynesian (NK) model, although it may have just added one equation to the RBC model, did something which corrected its central failure: the failure to acknowledge the pre-revolution wisdom about what causes business cycles and what you had to do to combat them. In that sense its break from its RBC heritage was profound. " 


Sticky output prices means the production system will face 
Episodic 
Bouts of involuntary unemployment 

Pretty 
Elegant restoration of potential " gains "
From state macro management


"You cannot understand macro today without going back to the New Classical revolution of the 1970s/80s. I often say that the war between traditional macro (Keynesian or Monetarist) and New Classical macro was won and lost on the battlefield of rational expectations. This was not just because rational expectations was such an innovative and refreshing idea, but also because the main weapon in the traditionalists armoury was so vulnerable to it. Take Friedman’s version of the Phillips curve, and replace adaptive expectations by rational expectations, and the traditional mainstream Keynesian story just fell apart. It really was no contest. (See Roger Farmer here, for example.)

I believe that revolution, and the microfoundations programme that lay behind it, brought huge improvements to macro. But it also led to a near death experience for Keynesian economics. I think it is fairly clear that this was one of the objectives of the revolution, and the winners of wars get to rewrite the rules. So getting Keynesian ideas back into macro was a slow process of attrition. The New Classical view was not overthrown but amended. New Keynesian models were RBC models plus sticky prices (and occasionally sticky wages), where stickiness was now microfounded (sort of). Yet from the New Classical point of view, New Keynesian analysis was not a fundamental threat to the revolution. It built upon their analysis, and could be easily dismissed with an assertion about price flexibility. Specifically NK models retained the labour leisure choice, which was at the heart of RBC analysis. Monetary policymakers were doing the Keynesian thing anyway, so little was being conceded in terms of policy. [1]