Paul Romer and microfoundations

For economists

In an AER P&P paper, Paul Romer talks about many things: a distinction between scientific consensus and political discourse, a divide in growth theory between those that use models based on perfect competition and those using imperfect competition, but mainly the distinction between appropriate mathematical theory and what he calls ‘mathiness’. To better see how these things connect up, and how they could have wider applicability, I suggest reading his blog post first. There he writes:

“the problems I identify in growth theory may be of broader interest. If economists can understand what the problem is in this sub-field, we may be in a better position to evaluate the scientific health of other parts of economics. The field to which scrutiny might first extend is economic fluctuations.”

So how might such a comparison go? The attachment to using perfect rather than imperfect competition could map into an aversion to either price stickiness or the importance/autonomy of aggregate demand, both of which could be labelled as ‘anti-Keynesian’. Keynesian theory is denigrated in some cases not because of empirical evidence but because of the policy implications that may follow from that theory. The microfoundations methodology, as practiced by some, allows those that want to deny the importance of Keynesian effects to continue to study business cycles, because this methodology can place such a low weight on the importance of evidence when it comes to the elements of model building. (Ask not whether price stickiness has empirical support, but whether it has solid microfoundations.)

Paul Romer’s post also links to the idea in this paper by Paul Pfleiderer about theoretical models becoming “chameleons”. To quote: “A model becomes a chameleon when it is built on assumptions with dubious connections to the real world but nevertheless has conclusions that are uncritically (or not critically enough) applied to understanding our economy.” I think we could add that these conclusions are usually associated with defending a particular political view or sectional interest.

It is important to stress that this is not an attack on the microfoundations methodology, just as Paul Romer’s article is not an attack on mathematical modelling. Most DSGE modellers, who are not subject to any political aversion to using price rigidity, happily use this methodology to advance the discipline. But if that methodology is taken too seriously (by what I call here microfoundations purists), so that modellers only look at what they can microfound rather than what they actually see in the real world, it can allow approaches that should have been discarded to live on, perhaps because they support a particular policy position.

A discipline where a huge number of alternative models persist could be described as ‘flourishing’, but risks disintegrating into alternative schools of thought, where some schools have an immunisation strategy that protects them from particular kinds of empirical evidence. As Paul perceptively points out, this makes economics more like political discourse than a scientific discipline. Some people welcome that, or regard it is inevitable - I hope most economists do not. This means we first need to collectively recognise the problem, rather than keeping our heads down to avoid upsetting others. I hope Paul Romer’s article can be part of that process. 

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Ditulis oleh AndreSurbakti pada tanggal Sabtu, 16 Mei 2015