The macro wars
September 17th, 2009
Paul Krugman’s piece on “Why did economists get it so wrong” has attracted a vitriolic response from John Cochrane, reproduced here. Krugman’s piece was strongly worded, but the reply ups the ante, and I expect further escalation. Economics conferences in the next few years are going to be interesting events.
Given that, as Krugman himself notes, disagreements between economists were notably mild until the crisis erupted, what is going on here?
I’m visiting Berkely at present and just had a chat with Brad DeLong. These are some of the thoughts I had about the great macroeconomics wars as a result.
One important element that can’t be ignored is the effect political partisanship, which is much more bitter in the US now than in most other places. It’s not so much Republicans vs Democrats as Republicans vs anti-Republicans. Krugman has been a leading figure in rejecting the idea that the Republican party represents a serious viewpoint that should be accorded respect, even in disagreement. Not surprisingly, the members of the intellectual class still associated with the Republican Party (relatively few, these days, but still dominant in Chicago) intensely dislike Krugman’s writing for the NYT.
But more important, I think, is the hole in the intellectual landscape opened up by the crisis. As regards macroeconomics, the pre-crisis near-consensus described by Krugman included a lot of “freshwater” macroeconomists whose intellectual roots go back to the New Classical/Real Business Cycle literature of the late 1970. This literature initially suggested that there was no possible role for monetary or fiscal policy unless people had mistaken expectations and drew the implication that a sufficiently credible and determined government could eliminate inflation without any serious cost in terms of output and employment, a theory tested to destruction by the Thatcher government.
Given the empirical difficulties encountered by strong forms of these views, most of the freshwater economists were prepared to make some concessions. As regards monetary policy, they were willing to accept some use of interest rates to target inflation, while arguing against “fine tuning” designed to stabilise the economy – during the Great Moderation it was easy enough to conclude that macro instability was a problem of the past, a claim made explicitly by Robert Lucas.
Similarly, it was easy enough to accept the implication that, in certain extreme circumstances like those of the Great Depression, the standard tools of monetary policy might prove ineffective necessitating direct use of fiscal policy to expand the money supply. In the absence of any perceived risk of a Depression, it was easy enough to make this concession while arguing against any use of active fiscal policy.
In the wake of the crisis, this position was untenable. If you supported fiscal policy at all, it was clear that a massive stimulus was needed. In fact, the arguments of Barro and others that Keynesians had overestimated the multiplier effects of fiscal stimulus implied that the required stimulus was even larger than Keynesian estimates would suggest.
Moreover, there is, as Brad DeLong and others have pointed out, no coherent position under which fiscal policy is totally ineffective while monetary policy is at least partly effective. And the only plausible conditions under which policy is totally ineffective is if the macroeconomy is always in (or close to) equilibrium. So, it’s essentially impossible to believe in recessions and unconditionally oppose fiscal policy.
So we see Cochrane forced all the way back to Say’s Law, the claim that it is logically impossible for (planned) supply to exceed (planned) demand, since willingness to supply, say, labour implies willingness to demand goods. Cochrane accuses Krugman of wanting to scrap the macroeconomics of the last forty years but then makes it clear enough that he wants to dump Keynes and everything that has been written since.
Arguments about Say’s Law are unlikely to be resolved by logical disputation. The only way to address them is to look at the historical record of the economy over the last couple of centuries. If you see stability, interrupted only by the occasional ill effects of government policies, you’ll accept Say’s Law. If you see regular crises, except for a few exceptional periods when macroeconomic stabilization policies have appeared to work, you’ll reject it.
fn1. Except for those who can always find some government program or another to blame, even for a case as clear cut as the 1890s Depression in Australia.
fn2. This charge is broadly correct, but I think the correct answer is the one anticipated by Cochrane. Economics did indeed take a wrong turn in the 1970s, responding to the breakdown of (one version of) Keynesianism. We need to find a new and better response, and much of the work of the past 40 years will have to be be discarded or reinterpreted as a result.