This post develops a point made by Bryan Caplan (HT MT). I have two stock complaints about the dominance of the microfoundations approach in macro. Neither imply that the microfoundations approach is ‘fundamentally flawed’ or should be abandoned: I still learn useful things from building DSGE models. My first complaint is that too many economists follow what I call the microfoundations purist position: if it cannot be microfounded, it should not be in your model. Perhaps a better way of putting it is that they only model what they can microfound, not what they see. This corresponds to a standard method of rejecting an innovative macro paper: the innovation is ‘ad hoc’.
My second complaint is that the microfoundations used by macroeconomists is so out of date. Behavioural economics just does not get a look in. A good and very important example comes from the reluctance of firms to cut nominal wages. There is overwhelming empirical evidence for this phenomenon (see for example here (HT Timothy Taylor) or the work of Jennifer Smith at Warwick). The behavioural reasons for this are explored in detail in this book by Truman Bewley, which Bryan Caplan discusses here. Both money illusion and the importance of workforce morale are now well accepted ideas in behavioural economics.
Yet debates among macroeconomists about whether and why wages are sticky go on. As this excellent example (I’ve been wanting to link to it for some time, just because of its quality) shows, they are not just debates between Keynesians and anti-Keynesians, so I do not think you can put this all down to some kind of ideological divide. I suspect nearly all economists are naturally reluctant to embrace cases where agents appear to miss opportunities for Pareto improvement - I give another example related to wage setting here. However in most other areas of the discipline overwhelming evidence is now able to trump these suspicions. But not, it seems, in macro.
While we can debate why this is at the level of general methodology, the importance of this particular example to current policy is huge. Many have argued that the failure of inflation to fall further in the recession is evidence that the output gap is not that large. As Paul Krugman in particular has repeatedly suggested, the reluctance of workers or firms to cut nominal wages may mean that inflation could be much more sticky at very low levels, so the current behaviour of inflation is not inconsistent with a large output gap. Work by the IMF supports this idea. Yet this is hardly a new discovery, so why is macro having to rediscover these basic empirical truths?
There may be an even more concrete example of the price paid for failing to allow for this non-linearity in wage behaviour. For all it inadequacies, the Eurozone Fiscal Compact does at least include a measure of the cyclically adjusted budget deficit among its many indicators that are meant to guide/proscribe fiscal policy. However, as Jeremie Cohen-Setton discusses here, the Commission now think they have been underestimating the output gap. As he suggests, the reason is pretty obvious: they have overestimated how much the natural rate of unemployment has risen in this recession. Here is the example he gives for Spain.
Actual unemployment and European Commission estimates of the NAWRU for Spain, from European Commission, 2013 spring forecast exercise. Source Jeremie Cohen-Setton
How could the Commission have been so foolish as to believe the natural rate had risen from 10% to 27% in a few years? Might it be because they looked at nominal wages in Spain, and inferred from the fact that nominal wages were not falling that therefore actual unemployment must be close to its natural rate? If empirical macromodels as a matter of course allowed for the absence of nominal wage cuts, would they have made such an obvious (to anyone who is not a macroeconomist) mistake?
I think this example illustrates why it can be dangerous to rely on DSGE models to guide policy. Yet the influence of DSGE models in policy making institutions is strong and growing. The Bank of England’s core forecasting model (pdf) is a fairly basic DSGE construct, and as far as I can see its wage equation is a standard New Keynesian specification, with no non-linearity when wage inflation approaches zero. Now I know the Bank have many other models they look at, and they will undoubtedly have looked at the implications of a reluctance to cut nominal wages. (I discuss the Bank’s ‘new’ model in more detail here.). However default positions are important, as the examples I discussed earlier show. Focusing on models where consistency with fairly simplistic microfoundations is all important, and consistency with empirical evidence is less of a concern, can distort the way macroeconomists think.