Simon Wren-Lewis continues the conversation on the state of academic macroeconomics:
Is academic macroeconomics flourishing?, by Simon Wren-Lewis: How do you judge the health of an academic discipline? Is macroeconomics rotten or flourishing? ...[A]cademic macroeconomics appears all over the place, with strong disputes between alternative schools.
Is this because the evidence in macroeconomics is so unclear that it becomes very difficult to judge different theories? I think the inexact nature of economics is a necessary condition for the lack of an academic consensus in macro, but it is not sufficient. (Mark Thoma has a recent post on this.) Consider monetary policy. I would argue that we have made great progress in both the analysis and practice of monetary policy over the last forty years. One important reason for that progress is the existence of a group that is often neglected - macroeconomists working in central banks.
Unlike their academic counterparts, the primary goal of these economists is not to innovate, but to examine the evidence and see what ideas work. The framework that most of these economists find most helpful is the New NeoClassical Synthesis, or equivalently New Keynesian theory. As a result, it has become the dominant paradigm in analyzing monetary policy.
That does not mean that every macroeconomist looking at monetary policy has to be a New Keynesian, or that central banks ignore other approaches. It is important that this policy consensus should be continually questioned, and part of a healthy academic discipline is that the received wisdom is challenged. However, it has to be acknowledged that policymakers who look at the evidence day in and day out believe that New Keynesian theory is the most useful framework currently around. I have no problem with academics saying ‘I know this is the consensus, but I think it is wrong’. However to say ‘the jury is still out' on whether prices are sticky is wrong. The relevant jury came to a verdict long ago.
It is obvious that when it comes to using fiscal policy in short term macroeconomic stabilization there can be no equivalent claim to progress or consensus. The policy debates we have today do not seem to have advanced much since when Keynes was alive. From one perspective this contrast is deeply puzzling. The science of fiscal policy is not inherently more complicated. ...
What has been missing with fiscal policy has been the equivalent of central bank economists whose job depends on taking an objective view of the evidence and doing the best they can with the ideas that academic macroeconomics provides. This group does not exist because the need to use fiscal policy for short term macroeconomic stabilization is occasional either in terms of time (when the Zero Lower Bound applies) or space (countries within the Eurozone). As a result, when fiscal policy was required to perform a stabilization role, policymakers had to rely on the academic community for advice, and here macroeconomics clearly failed. Pretty well any outside observer would describe its performance as rotten.
The contrast between monetary and fiscal policy tells us that this failure is not an inevitable result of the paucity of evidence in macroeconomics. I think it has a lot more to do with the influence of ideology, and the importance of what I have called the anti-Keynesian school that is a legacy of the New Classical revolution. The reasons why these influences are particularly strong when it comes to fiscal policy are fairly straightforward.
Two issues remain unclear for me. The first is how extensive this ideological bias is. Is the over dominance of the microfoundations approach related to the fact that different takes on the evidence have an unfortunate Keynesian bias? Second, is the degree of ideological bias in macro generic, or is it in part contingent on the particular historical circumstances of the New Classical revolution? These questions are important in thinking how this bias can be overcome.
When people ask if evidence matters in economics, I often point to the debate over the New Classical model's prediction that only unexpected changes in monetary policy matter for economic activity. These models, with their prediction that expected changes in monetary policy are neutral, cleverly allowed New Classical economists to explain the correlations between money, output, and prices in the data without admitting that systematic policy mattered. Thus, these models supported the ideological convictions of many on the right -- government intervention can make things worse, but not better. (Unexpected policy shocks push the economy away from the optimal outcome, so the key was to minimize unexpected policy shocks. This led to things like the push for transparency so that people would anticipate, as much as possible, actual policy moves.)
At first, the evidence seemed to support these models (e.g. Barro's empirical work), but as the evidence accumulated it eventually became clear that this prediction was wrong. Mishkin provided key evidence against these models through his academic work (see, for example, his book A Rational Expectations Approach to Macroeconometrics: Testing Policy Ineffectiveness and Efficient-Markets Models), so I am not as convinced as Simon Wren-Lewis that the difference between monetary and fiscal policy is due solely to the existence of technocratic, mostly non-ideological central bank economists letting the evidence take them where it may. That certainly mattered, but is seems there was more to it than this.
The evidence that Mishkin and others provided was a key reason these models were rejected (it was also difficult to simultaneously explain the magnitude and duration of business cycles with unexpected monetary shocks as the sole driving force), but when it comes to fiscal policy, as noted above, evidence has not trumped ideology to the same degree. One of the reasons for this, I think, is that it's difficult to find clear fiscal policy experiments in the data to evaluate. And when we do (e.g. wars), it's difficult to know if the results will hold at other times. But I can't really disagree with the hypothesis that if an institution like the Fed existed for fiscal policy, there would be a much bigger demand for this information, and that demand would have produced a much larger supply of evidence.
But I am not so sure the difference is "central bank economists whose job depends on taking an objective view of the evidence" so much as it is that these institutions produce a demand for this type of research, and academics respond by supplying the information that central banks need. So the question for me is whether it's the lack of ideology of central bank economists (many of whom are academics), or the fact that their existence creates a large demand for this type of information. Maybe it's both.