tirsdag 7. februar 2012

WEITZMANS VAKRE SINN

I masterfaget i miljø- og ressursøkonomi som jeg foreleser dette semesteret hadde to heldige studenter gleden av å presentere Martin L. Weitzmans artikkel Prices vs. Quantities (Review of Economic Studies, 1974) for sine medstudenter (og meg) sist uke.

Under streng instruks om å bruke maksimum 15 minutter fordelt på mindre enn 10 Powerpoint foiler med fokus på å gjenfortelle artikkelens grunnleggende samfunnsøkonomisk intuisjon verbalt og grafisk gjorde disse studentene en fantastisk jobb!

Jeg leste selv gjennom artikkelen dagen i forveien, og ble for n’te gang påminnet dens eleganse og tidløshet. Blantannet er artikkelen høyst relevant til debatten omkring hva som er den beste tilnærmingen til global klimapolitikk: CO2-skatt eller kvotesystem. Med fare for å komme i opphavsrettighetstrøbbel, her er en komplett reproduksjon av artikkelens første side:
The setting for the problem under consideration is a large economic organization or system which in some cases is best thought of as the entire economy. Within this large economic organization resources are allocated by some combination of commands and prices (the exact mixture is inessential) or even by some other unspecified mechanism. The following question arises. For one particular isolated economic variable that needs to be regulated, what is the best way to implement control for the benefit of the organization as a whole? Is it better to directly administer the activity under scrutiny or to fix transfer prices and rely on self-interested profit or utility maximization to achieve the same ends in decentralized fashion? This issue is taken as the prototype problem of central control which is studied in the present paper. There are a great many specific examples which fit nicely into such a framework. One of current interest is the question of whether it would be better to control certain forms of pollution by setting emission standards or by charging the appropriate pollution taxes.

When quantities are employed as planning instruments, the basic operating rules from the centre take the form of quotas, targets, or commands to produce a certain level of output. With prices as instruments, the rules specify either explicitly or implicitly that profits are to be maximized at the given parametric prices. Now a basic theme of resource allocation theory emphasizes the close connection between these two modes of control. No matter how one type of planning instrument is fixed, there is always a corresponding way to set the other which achieves the same result when implemented. From a strictly theoretical point of view there is really nothing to recommend one mode of control over the other. This notwithstanding, I think it is a fair generalization to say that the average economist in the Western marginalist tradition has at least a vague preference toward indirect control by prices, just as the typical non-economist leans toward the direct regulation of quantities. When quantities are employed as planning instruments, the basic operating rules from the centre take the form of quotas, targets, or commands to produce a certain level of output. With prices as instruments, the rules specify either explicitly or implicitly that profits are to be maximized at the given parametric prices. Now a basic theme of resource allocation theory emphasizes the close connection between these two modes of control. No matter how one type of planning instrument is fixed, there is always a corresponding way to set the other which achieves the same result when implemented. From a strictly theoretical point of view there is really nothing to recommend one mode of control over the other. This notwithstanding, I think it is a fair generalization to say that the average economist in the Western marginalist tradition has at least a vague preference toward indirect control by prices, just as the typical non-economist leans toward the direct regulation of quantities.

That a person not versed in economics should think primarily in terms of direct controls is probably due to the fact that he does not comprehend the full subtlety and strength of the invisible hand argument. The economist's attitude is somewhat more puzzling. Understanding that prices can be used as a powerful and flexible instrument for rationally allocating resources and that in fact a market economy automatically regulates itself in this manner is very different from being under the impression that such indirect controls are generally preferable for the kind of problem considered in this paper. Certainly a careful reading of economic theory yields little to support such a universal proposition.
Denne artikkelen er ikke bare et enkeltstående mesterverk i den samfunnsøkonomiske vitenskapen, den er også representativ for den generelle brilliansen man finner i Weitzmans miljøøkonomisike forskning gjennom en lang karriere. Weitzman kan også sies å ha et vakkert sinn som i nærmeste fremtid burde bli tildelt Nobelsprisen i Økonomi!

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