La economía fácil de Krugman para un mundo complejo...

Hay gente que quiere complicar la discusión sobre el mercado petrolero, dice Paul Krugman en una entrada de su blog. La suya es una explicación sencilla que prueba una de las hipótesis sobre el alza de los precios, la de la existencia de una burbuja. La burbuja es una situación de desequilibrio con precios altos, de modo tal que hay una sobreoferta. Krugman argumenta "una de dos": o te consumes el excedente, o lo guardas. Los datos no indican acumulación de inventarios por ningún lado, dice Krugman, por lo que hay que rechazar la hipótesis de la burbuja petrolera... Reproducimos aquí la breve entrada:
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More on oil and speculation

One of the things I find puzzling about the whole oil market discussion is how complicated people seem to make it. They get all wrapped up in stuff about forward markets, hedge funds, etc., and lose sight of the fundamental fact that there are only two things you can do with the world’s oil production: consume it, or store it.

Here’s my picture:

It’s not complicated

If the price is above the level at which the demand from end-users is equal to production, there’s an excess supply — and that supply has to be going into inventories. End of story. If oil isn’t building up in inventories, there can’t be a bubble in the spot price.

Now it’s true that oil supply responds very little to price, and that empirical estimates of the short-run price elasticity of demand, like this one, suggest that it’s low — say -.06. But even so, the math of a sustained, large bubble quickly becomes daunting. Say the demand elasticity is -.06, and that you believe that the current price is 40% above the level at which end-use demand equals supply. Then you have to believe that 2 million barrels a day is disappearing into secret hoards somewhere — secret, because it’s not showing up in the OECD inventory data. That’s a lot of oil. And bear in mind that people have been claiming that there’s an oil bubble for years.

So my challenge to people who say there’s an oil bubble is this: let’s get physical. Tell me where you think the excess supply of crude is going.

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Buen modo de intervenir en la discusión (sencillo, y con un argumento analítico simple y que sirve como buen vehículo para llevar el mensaje). Si la hipótesis de Krugman tiene relevancia (la de la no-existencia de la burbuja petrolera) entonces el reto que lanza es díficil y, en efecto, tendría que ser atendido por los que sugieren que sí hay burbuja. Sin embargo, Krugman parece basar su argumento suponiendo que el precio "spot" del crudo depende únicamente de los fundamentales clásicos del mercado (es decir, precios y cantidades corrientes), sin abrir la posibilidad de que dicho precio pueda estar influído también por los futuros del mercado. Los comentaristas de la entrada de Krugman parecen argumentar este punto.

En su columna en El Universal se ofrece el argumento. Esta vez en español, y lo reproducimos aquí:

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Mirada al mundo Paul Krugman 22 de mayo de 2008

La no burbuja petrolera

“¿Está a punto de estallar la burbuja petrolera?” Este fue el encabezado de un reportaje de octubre de 2004 en la revista National Review, que sostenía que los precios del petróleo, entonces en 50 dólares el barril, pronto se derrumbarían

Diez meses después, el petróleo se cotizaba en 70 dólares el barril. “Es una enorme burbuja”, declaró Steve Forbes, el editor, que advirtió que el próximo hundimiento de los precios petroleros haría que el estallido de la burbuja tecnológica “parezca un día de campo”.

A lo largo de los cinco años que lleva el repunte petrolero, que ha llevado el precio de 25 a 125 dólares el barril la semana pasada, han surgido muchas voces que declaran que se trata de una burbuja sin respaldo en los fundamentos de la oferta y la demanda.

Ante esta posición existen dos preguntas: ¿son los especuladores los principales responsables de los precios del petróleo? Y si no es así, ¿por qué tantos comentaristas han insistido, año tras año, en que existe una burbuja petrolera?

Es cierto que los especuladores en ocasiones empujan los precios de las materias primas muy por encima del nivel justificado por los fundamentos. Pero cuando eso sucede, existen indicios que simplemente no se ven en el mercado petrolero actual.

Imagine qué pasaría si el mercado petrolero registrara, con la oferta y la demanda en equilibrio, un precio de 25 dólares el barril y entonces un grupo de especuladores lo manipulara para llevar el precio a los 100 dólares.

Incluso si fuera una intervención puramente financiera de los especuladores, tendría serias consecuencias en el mundo material. Ante el alza de los precios, los conductores usarían menos el auto, los propietarios de casas le bajarían a su termostato, y los dueños de pozos casi agotados volverían a explotarlos.

Como resultado, el balance inicial entre oferta y demanda se desmoronaría y sería sustituido por una situación en la que la oferta rebasaría a la demanda. A su vez, este exceso de oferta empujaría los precios a la baja nuevamente, a menos que alguien estuviera dispuesto a comprar el exceso y sacarlo del mercado.

Por lo tanto, la única forma en que la especulación puede tener un efecto persistente sobre los precios petroleros es si provoca una acumulación física, esto es, un aumento en los inventarios privados de oro negro. Esto de hecho sucedió a finales de los 70, cuando los efectos de la interrupción del abastecimiento iraní fueron amplificados por la acumulación de reservas causada por el pánico.

Pero eso no ha sucedido esta vez: durante todo el periodo de la supuesta burbuja, los inventarios han permanecido más o menos en sus niveles normales. Esto nos dice que el alza de los precios petroleros no es resultado de una especulación desenfrenada, sino de la situación de los factores fundamentales, en especial la creciente dificultad para encontrar petróleo y el rápido crecimiento de economías emergentes como China. El aumento de los precios petroleros de los últimos años tenía que presentarse para evitar que el crecimiento de la demanda superara el aumento de la oferta.

Decir que los altos precios del petróleo no son una burbuja no implica que éstos nunca van a descender; no me sorprendería que un retroceso en la demanda, impulsado por los efectos retrasados de los altos precios, enviara los precios de regreso a un nivel inferior a los 100 dólares por un rato. Pero sí significa que los especuladores no son los únicos protagonistas de esta historia. ¿Por qué, entonces, seguimos escuchando declaraciones de que sí lo son?

Parte de la respuesta podría ser el incontrovertible hecho de que muchas personas están invirtiendo ahora en contratos a futuro de petróleo, lo cual alimenta la sospecha de que son especuladores los que deciden el rumbo de la situación, aun cuando no hay evidencia convincente de que los precios se han salido de control.

Pero también hay un componente político.

Tradicionalmente, las denuncias contra los especuladores proceden del lado izquierdo del espectro político.

En el caso de los precios del petróleo, empero, los más vociferantes promotores de la opinión de que todo es culpa de los especuladores han sido conservadores, gente de la que normalmente no se esperaría que lanzara advertencias sobre las funestas actividades de los bancos de inversión y fondos de cobertura.

La explicación de esta aparente paradoja es que los buenos deseos han destronado a la ideología de mercado.

Después de todo, una lectura realista de lo sucedido en los últimos años sugiere que nos dirigimos a una época de petróleo cada vez más costoso y escaso.

Las consecuencias de esa escasez probablemente no serán apocalípticas: Francia consume solamente la mitad de petróleo per cápita que Estados Unidos y sin embargo la última vez que estuve ahí París no era un yermo desolado.

Pero lo más probable es que en el futuro la conservación de energía sea cada vez más importante y mucha gente incluso utilice el transporte público para ir al trabajo.

Esta visión no me parece particularmente aborrecible, pero para mucha gente, especialmente de la derecha, sí lo es y por lo tanto quiere creer que si solamente Goldman Sachs abandonara esa actitud tan negativa, rápidamente volveríamos a los viejos y buenos días del petróleo abundante.

Nuevamente, no me sorprendería que los precios del petróleo bajaran en el futuro cercano, aunque tomo seriamente la reciente advertencia de Goldman de que el precio podría alcanzar los 200 dólares.

Pero hagamos a un lado esa idea de la burbuja petrolera. (Traducción: Gregorio Narváez)

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Lo que sugiere Krugman es que los precios elevados en el mercado petrolero no se deben a la especulación sobre los futuros, sino a desplazamientos convencionales de las curvas de oferta y de demanda: la de oferta al noroeste debido a la presumida escasez en las reservas (Cantarell, por ejemplo), la de demanda al sureste por el empuje chino... Mientras que poco se puede decir sobre si estos desplazamientos provocan una reducción o un aumento en la cantidad de equilibrio (pues eso dependerá de la magnitud de los desplazamientos), no hay lugar a la ambigüedad en cuanto al precio: éste subirá.

A Core of Practical Macroeconomics

A Core of Practical Macroeconomics

JOHN B. TAYLOR

The American Economic Review, Vol. 87, No. 2, Papers and Proceedings of the Hundred and Fourth Annual Meeting of the American Economic Association, (May, 1997), pp. 233-235

Macroeconomics-the part of economics that focuses on economic growth and economic fluctuations-has always been an area of great controversy and debate. Over 150 years ago David Ricardo argued with Thomas Malthus over the importance of supply versus demand in growth and fluctuations, much as real-business-cycle economists have argued with monetarists and Keynesians in recent years. The Keynesian revolution of the 1930's and the rational-expectations revolution of the 1970's, both questioning macroeconomic ideas of the time, were two of the most contentious episodes in the history of economic thought. Some view recent macroeconomic debates as so intense that they see macroeconomics as nothing more than competing camps of economists with no common set of core principles.

I welcomed the opportunity to appear on this panel because, in my view, there is a set of key principles -a core -of macroeconomics about which there is wide agreement. This core is the outgrowth of the many recent debates about Keynesianism, monetarism, neoclassical growth theory, real-business-cycle theory, and rational expectations. The core is practical in the sense that it is having a beneficial effect on macroeconomic policy, especially monetary policy, and has resulted in improvements in policy in the last 15 years. In fact, new econometric models recently put in operation at the Fed largely reflect this core. This core is increasingly evident in undergraduate economics texts, and it also appears in graduate training, though in most Ph.D. programs there is much more emphasis on the newer and more controversial parts.

Although there are different ways to characterize this core, I would list five key principles. I would start with the most basic and least controversial principle, focusing on longterm economic growth and the supply side of the economy. Over the long term, labor productivity growth depends on the growth of capital per hour of work and on the growth of technology or, more precisely, on movements along as well as shifts of a production function, as Robert Solow pointed out many years ago. If one adds to this labor productivity growth an estimate of labor-force growth, one gets an estimate of the long-run growth rate of real GDP, or what is typically referred to as potential GDP growth. This principle, the essence of neoclassical growth theory, provides a way to estimate and discuss the sources of long-term economic growth within the organizing structure of the growth accounting formula. Key policy questions to address within this framework, of course, are why potencial GDP growth has declined and what can be done to raise it again.

Is this first principle practical? Yes. Public policy economists at the Fed and the Congressional Budget Office and private industry economists regularly use this approach to get estimates of potential GDP growth. Most now estimate this growth to be about 2-2.5 percent per year. Of course there are debates about how to apply this principle: Are there diminishing returns to information capital? How much would fundamental tax reform raise the capital-labor ratio? How much does a reducción in marginal tax rates increase labor supply? But these are more quantitative issues, concerning the size of elasticities, rather than matters of principle.

A second key macroeconomic principle is that there is no long-term trade-off between the rate of inflation and the rate of unemployment; a corollary is that a shift by the central bank to a higher rate of money growth will simply result in more inflation in the long run, with the unemployment rate remaining unchanged. Although controversial at one time, this does not appear to be controversial anymore; empirical and theoretical research provides strong support. In the 1960's inflación was low, and unemployment was between 5 percent and 6 percent; in the 1970's inflation was high, and unemployment was no lower; and in the 1990's inflation is low again, and unemployment has not increased. There are two qualifications to this principle: (i) inter-national evidence from different countries in-dicates that high rates of inflation appear to reduce the growth of potential GDP, and (ii) very low rates of inflation, in particular defla-tion, may be an impediment to the smooth op-eration of markets, both because of a lower bound on the nominal interest rate and because of the stickiness of prices and wages.

This second principle has already had a majorpractical impact on policy. It implies that central banks should pick a long-run target range for inflation and stick with it. Many central banks around the world are doing just that either explicitly as with New Zealand and the United Kingdom or implicitly as with the United States and Germany. A third principle is that there is a short-run trade-off between inflation and unemployment. In my view this trade-off is best described as one between the variability of inflation and the variability of unemployment. There is still debate about the reason for this trade-off. One rationale is the sticky-price/staggered-wage theory which I favor; but there is also the information-based theory put forth by Robert Lucas. There is also an Chongoing debate about the monetary transmission mechanism: does monetary policy work through a money channel, a credit channel, or through a financial price channel (interest rates and exchange rates)?

Despite these debatable underpinnings, the existence of a short-run trade-off has practical implications for policy: monetary policy should keep the growth of aggregate demand stable in order to prevent fluctuations in real output and inflation. In fact, the improvements of monetary policy during the last 15 years have led to much more stable macroeconomic conditions. The United States is now experiencing, back-to-back, the two longest peacetime expansions ( 1982-1990 and 1991-1997) in U.S. history, separated by one of the mildest recessions in U.S. history (1990- 1991 ). A greater stability of monetary policy, including explicit discussions and actions consistent with the goal of keeping inflation low, is largely responsible for this record-brea King macroeconomic stability. Every recession since the 1950's has been preceded by a run up of inflation; by keeping inflation from ricino in the first place, the chances of such recessions are diminished. A fourth macroeconomic principle is that peoples' expectations are highly responsive to policy, and thus, expectations matter for assessing the impact of monetary and fiscal policy. The most feasible empirical way to model this response or endogeneity of expectations is the rational-expectations approach, though modifications to take account of differing degrees of credibility are necessary. By introducing rational expectations into fully estimated econometric models and then simulating the models for different policies, the response of expectations to changes in policy can be reasonably approximated (see Taylor, 1993).

Is this fourth principle having an impact on practice? Yes. For example, macroeconomic models with rational expectations now in use at the Fed are able to estimate the effects on interest rates of a multiyear plan to reduce the future budget deficit (see Flint Brayton et al., 1997). These models can help guide monetary decisions about interest rates when a plan for budget deficit reduction (like that in 1990 or 1993 in the United States) is being considered. Additional evidence for the practical relevance of this principle is the great emphasis placed on credibility by central banks today. According to rational-expectations models, there are advantages to credibility in both monetary policy and fiscal policy. For example, a disinflation will have lower short-run costs if policy is credible. Similarly, a plan to reduce the budget deficit will have a smaller short-run contractionary effect if it is credible. A fifth principle is that when evaluating monetary and fiscal policy one should not think in terms of a one-time isolated change in the instruments of policy, but rather as a series of changes linked by a systematic process or a policy rule. This fifth principle follows from many of the other principles. It is very evidente in academic policy-evaluation research during the past 15 years, where virtually all formal policy evaluation has been done in terms ofpolicy rules. To be sure there is debate about the form of the policy rules: Should the interest rate or the money supply be the instruments in the rule? Should the instrument react to the exchange rate or solely to inflation and real output? How large should the reaction of pol-icy be to inflation? Is the rule a guideline or should it be legislated and used to add ac-countability to policy-making?

Recently there has been increased practicali nterest in policy rules. For example, in recent speeches, Federal Reserve Board Governors Laurence Meyer ( 1996) and Janet Yellen (1996) have described in detail how policy rules can be helpful in the formulation of monetary policy. Speaking about her practical experience on the Federal Reserve Board, Yellen states (p. 10) that "... rules provide a simple but useful benchmark to assess the setting of monetary policy in a very complex and uncertain economic environment." The Federal Reserve Board staff now regularly does stochastic simulation of alternative policy rules. And many private-sector business economists have noted the similarity between the actions of the Fed and many other central banks to the outcomes implied by certain policy rules.

In conclusion, let me emphasize that this characterization of a core of practical macroeconomics is not meant to imply that everything is settled in macroeconomics. On the contrary, there are still great debates going on over the size of elasticities, the role of credit in the monetary transmission mechanism, the empirical relevance of "endogenous" growth models, whether staggered price-setting models with rational expectations fit satisfactorily the dynamic correlations that characterize the process of inflation in the United States, and many other issues. One question that will continue to be debated for many years is how much formal optimization is appropriate in order to provide a solid underpinning to macroeconomics. Many of the macroeconomic models I referred to in this discussion are economy-wide generalequilibrium models which have sticky-price equations as part of their structure; but there is still much more work to be done to fully establish the optimization basis for many of these sticky price structures. The current effort to incorporate money and sticky prices into real-business-cycle models will hasten the day when models with a more fully articulated optimization structure are used in practice for policy-making. I believe that this work will add much to economists' understanding of the macroeconomic principles summarized in this discussion, but in the meantime, there is a solid core of macroeconomic principles which is useful in practical policy work and which has already improved macroeconomic policymaking in the United States and other countries.

REFERENCES

Brayton, Flint; Levin, Andrew; Tryon, Ralph andWilliams, John. "The Evolution of MacroModels at the Federal Reserve Board." Carnegie Rochester Series on Public Policy, 1997 (forthcoming).

Meyer, Laurence H. "Monetary Policy Objectives and Strategy." Remarks before the National Association of Business Economists 38th Annual Meeting, Board of Governors of the Federal Reserve System, Washington, DC, 8 September 1996.

Taylor, John B. Macroeconomic policy in a world economy. New York: Norton, 1993.

Yellen, Janet. "Monetary Policy: Goals and Strategy." Remarks before the National Association of Business Economists, Board of Governors of the Federal Reserve System, Washington, DC, 13 March 1996.