Tole zgodbo moram deliti z vami. John Cochrane iz University of Chicago jo je res dobro napisal. Gre v bistvu za to, kako se je ekonomska teorija 35 let trudila, da bi ubila zelo preprosto intuicijo keynesianizma, ki sicer deluje, nima pa (mikro)ekonomske podlage (v hiper racionalnih posameznikih in hiper racionalnih trgih). Intuicija keynesianizma je preprosta: ker pač v času krize zaradi povečane negotovosti nihče noče trošiti, mora pač začasno več trošiti država in zagnati gospodarsko rast, nakar se spet umakne in odpravi povečan javni dolg, ki je zaradi tega nastal.
Problem je seveda v tem, da mainstream (neoklasična) ekonomska teorija te preproste intuicije ne odobrava, ker pač ne temelji na (mikro)ekonomski podlagi hiper racionalnih posameznikov in hiper racionalnih trgov. Zato je nova struja otrokov pošasti keynesianizma izvedla trik: uporabila je mikrofundacijo (predpostavke) neoklasike, da bi pokazala isto kot stari Keynes (da povečanje javnega trošenja v času krize stimulira gospodarsko rast), da bi te svoje ideje sploh lahko objavila v najvišje rangiranih akademskih revijah (ki jih kontrolirajo neoklasiki). *
Many Keynesian commentators have been arguing for much more stimulus. They like to write the nice story, how we put money in people’s pockets, and then they go and spend, and that puts more money in other people’s pockets, and so on.
But, alas, the old-Keynesian model of that story is wrong. It’s just not economics. A 40 year quest for “microfoundations” came up with nothing. How many Nobel prizes have they given for demolishing the old-Keynesian model? At least Friedman, Lucas, Prescott, Kydland, Sargent and Sims. Since about 1980, if you send a paper with this model to any half respectable journal, they will reject it instantly.
But people love the story. Policy makers love the story. Most of Washington loves the story. Most of Washington policy analysis uses Keynesian models or Keynesian thinking. This is really curious. Our whole policy establishment uses a model that cannot be published in a peer-reviewed journal. Imagine if the climate scientists were telling us to spend a trillion dollars on carbon dioxide mitigation — but they had not been able to publish any of their models in peer-reviewed journals for 35 years.
What to do? Part of the fashion is to say that all of academic economics is nuts and just abandoned the eternal verities of Keynes 35 years ago, even if nobody ever really did get the foundations right. But they know that such anti-intellectualism is not totally convincing, so it’s also fashionable to use new-Keynesian models as holy water. Something like “well, I didn’t read all the equations, but Woodford’s book sprinkles all the right Lucas-Sargent-Prescott holy water on it and makes this all respectable again.” Cognitive dissonance allows one to make these contradictory arguments simultaneously.
Except new-Keynesian economics does no such thing, as I think this example makes clear. If you want to use new-Keynesian models to defend stimulus, do it forthrightly: “The government should spend money, even if on totally wasted projects, because that will cause inflation, inflation will lower real interest rates, lower real interest rates will induce people to consume today rather than tomorrow, we believe tomorrow’s consumption will revert to trend anyway, so this step will increase demand. We disclaim any income-based “multiplier,” sorry, our new models have no such effect, and we’ll stand up in public and tell any politician who uses this argument that it’s wrong.”
That, at least, would be honest. If not particularly effective!
You may disagree with all of this, but that reinforces another important lesson. In macroeconomics, the step of crafting a story from the equations, figuring out what our little quantitative parables mean for policy, and understanding and explaining the mechanisms, is really hard, even when the equations are very simple. And it’s important. Nobody trusts black boxes. The Chicago-Minnesota equilibrium school never really got people to understand what was in the black box and trust the answers. The DSGE new Keynesian black box has some very unexpected stories in it, and is very very far from providing justification for old-Keynesian intuition.
Vir: John Cochrane
* Disclaimer: Da ne bo pomote, ne spadam ne v šolo neoklasike, ne keynesianizma in ne neo-keynesianizma, niti nobenega drugega -izma. Zanima me zgolj zdrava kmečka pamet in intuicija ter pragmatičen pristop k reševanju problemov ne glede na ideologijo.