'John and Maynard’s Excellent Adventure'

Paul Krugman defends IS-LM analysis (I'd make one qualification. Models are built to answer specific questions, we do not have one grand unifying model to use for all questions. IS-LM models were built to answer exactly the kinds of questions we encountered during the Great Recession, and the IS-LM model provided good answers (especially if one remembers where the model encounters difficulties). DSGE models were built to address other issues, and it's not surprising they didn't do very well when they were pushed to address questions they weren't designed to answer. The best model to use depends upon the question one is asking):

John and Maynard’s Excellent Adventure: When I tell people that macroeconomic analysis has been triumphantly successful in recent years, I tend to get strange looks. After all, wasn’t everyone predicting lots of inflation? Didn’t policymakers get it all wrong? Haven’t the academic economists been squabbling nonstop?

Well, as a card-carrying economist I disavow any responsibility for Rick Santelli and Larry Kudlow; I similarly declare that Paul Ryan and Olli Rehn aren’t my fault. As for the economists’ disputes, well, let me get to that in a bit.

I stand by my claim, however. The basic macroeconomic framework that we all should have turned to, the framework that is still there in most textbooks, performed spectacularly well: it made strong predictions that people who didn’t know that framework found completely implausible, and those predictions were vindicated. And the framework in question – basically John Hicks’s interpretation of John Maynard Keynes – was very much the natural way to think about the issues facing advanced countries after 2008. ...

I call this a huge success story – one of the best examples in the history of economics of getting things right in an unprecedented environment.

The sad thing, of course, is that this incredibly successful analysis didn’t have much favorable impact on actual policy. Mainly that’s because the Very Serious People are too serious to play around with little models; they prefer to rely on their sense of what markets demand, which they continue to consider infallible despite having been wrong about everything. But it also didn’t help that so many economists also rejected what should have been obvious.

Why? Many never learned simple macro models – if it doesn’t involve microfoundations and rational expectations, preferably with difficult math, it must be nonsense. (Curiously, economists in that camp have also proved extremely prone to basic errors of logic, probably because they have never learned to work through simple stories.) Others, for what looks like political reasons, seemed determined to come up with some reason, any reason, to be against expansionary monetary and fiscal policy.

But that’s their problem. From where I sit, the past six years have been hugely reassuring from an intellectual point of view. The basic model works; we really do know what we’re talking about.

[The original is quite a bit longer.]