John Cochrane, profesor ekonomije na Chicago University, sicer deklarirani neoklasik ter anti-keynesianec in anti-neokeynesianec in kar je še teh predalčkov, je napisal zanimiv povzetek neoklasične revolucije v makroekonomiji. V prvih dveh sklopih obravnava Lucas – Sargentovo kritiko keynesianske makroekonomije (glej “After Keynesian Macroeconomics“), v zadnjem sklopu pa razmišlja ali je neoklasična revolucija resnično zmagala. Njegova ugotovitev je lucidna: neoklasična revolucija je sicer zmagala v akademskem svetu (prevlada DSGE modelov) in centralne banke širom sveta imajo v kleti velike DSGE modele, vendar njihovih rezultatov nihče ne jemlje resno. Medtem ko se akademiki igrajo s svojimi igračkami, pa se tisti, ki delajo ekonomsko politiko, raje zanašajo na preproste izračune ter svoje izkušnje in občutke.

In ta ugotovitev ni daleč od resnice.

As I survey the landscape now, it is interesting how much of the macroeconomics Lucas and Sargent praised has vanished. Quantitative, scientific discipline? Explicit statistical descriptions of economic behavior? Reliance of government officials on technical economic expertise? The use of mathematical control theory to manage an economy? All that has vanished.

The sub-basements of central banks have big DSGE models, or combined models where you can turn Lucas and Sargent on and off. But I think it’s fair to say nobody takes the results very seriously. Policy — our stimulus, for example — is based on back of the envelope multipliers and the authority and expertise, if you’re charitable, or the unvarnished, verbal, opinions if you’re not, of administration officials.

There are some large-scale empirical DSGE models left in academia too. But the vast bulk of policy analysis does not use them, as they did, say, the models of 1972. At conferences and in papers, academic work uses small scale toy models and a lot of words. Models do not seem to be cumulative. Each paper adds a little twist ignoring all the previous little twists.

A complete split occurred. “Equilibrium” models, in which I include new-Keynesian DSGE models, took over academia. The policy world stuck with simple ISLM logic — not “models” in the quantitative scientific tradition Lucas and Sargent praised — despite Lucas and Sargent’s devastating criticism.   And, as I remarked in the earlier blog posts, the “purely verbal” or literary style of analysis is becoming more and more common now in academia as well as policy.

I’m not complaining about good vs. bad here. I write simpler and simpler models as I grow older, and spend more time thinking and writing about what those equations mean. It just is a fact about how we do things today and the “scientific,” quantitative status of macroeconomics.

Vir: John Cochrane, Lucas and Sargent Revisited