LARS P. SYLL

Keynes vs. Samuelson on models

To his credit Keynes was not, in contrast to Samuelson, a formalist who was committed to mathematical economics. Keynes wanted models, but for him, building them required ‘ a vigilant observation of the actual working of our system.’ Indeed, ‘to convert a model into a quantitative formula is to destroy its usefulness as an instrument of thought.’ That conclusion can be strongly endorsed!
 

Economics — still in the land of Mordor

When it comes to my economics training, I’m a late bloomer. My primary training is in evolutionary theory, which I have used as a navigational guide to study many human-related topics, such as religion. But I didn’t tackle economics until 2008 …

At the time I had no way to answer this question. Economic jargon mystified me—an embarrassing confession, since I am fully at home with mathematical and computer simulation models. Economists were very smart, very powerful, and they spoke a language that I didn’t understand. They won Nobel Prizes.

Nevertheless, I had faith that evolution could say something important about the regulatory systems that economists preside over, even if I did not yet know the details …

Fortunately, I had a Fellowship of the Ring to rely upon … Some of my closest colleagues are highly respected economists, Herbert Gintis, Samuel Bowles, and Ernst Fehr …

I already knew from their work that the main body of modern economics, called neoclassical economics, was being challenged by a new school of thought called experimental and behavioural economics …

I was disappointed. My colleagues such as Herb, Sam, and Ernst confirmed my own impression: They appreciated the relevance of evolution but were a tiny minority among behavioral and experimental economists, who in turn were a tiny minority among neoclassical economists …

The more I learned about economics, the more I discovered a landscape that is surpassingly strange. Like the land of Mordor, it is dominated by a single theoretical edifice that arose like a volcano early in the 20th century and still dominates the landscape. The edifice is based upon a conception of human nature that is profoundly false, defying the dictates of common sense, before we even get to the more refined dictates of psychology and evolutionary theory. Yet, efforts to move the theory in the direction of common sense are stubbornly resisted.

David Sloan Wilson

[h/t Tom Hickey]

What is Post Keynesian economics?

‘New Keynesian’ DSGE models

In the model [Gali, Smets and Wouters, Unemployment in an Estimated New Keyesian Model (2011)] there is perfect consumption insurance among the members of the household. Because of separability in utility, this implies that consumption is equalized across all workers, whether they are employed or not … Workers who find that they do not have to work are unemployed or out of the labor force, and they have cause to rejoice as a result. Unemployed workers enjoy higher utility than the employed because they receive the same level of consumption, but without having to work.

There is much evidence that in practice unemployment is not the happy experience it is for workers in the model.  For example, Chetty and Looney (2006) and Gruber (1997) find that US households suffer roughly a 10 percent drop in consumption when they lose their job. According to Couch and Placzek (2010), workers displaced through mass layoffs suffer substantial and extended reductions in earnings. Moreover, Oreopoulos, Page and Stevens (2008) present evidence that the children of displaced workers also suffer reduced earnings. Additional evidence that unemployed workers suffer a reduction in utility include the results of direct interviews, as well as findings that unemployed workers experience poor health outcomes. Clark and Oswald (1994), Oswald (1997) and Schimmack, Schupp and Wagner (2008) describe evidence that suggests unemployment has a negative impact on a worker’s self-assessment of well being. Sullivan and von Wachter (2009) report that the mortality rates of high-seniority workers jump 50-100% more than would have been expected otherwise in the year after displacement. Cox and Koo (2006) report a significant positive correlation between male suicide and unemployment in Japan and the United States. For additional evidence that unemployment is associated with poor health outcomes, see Fergusson, Horwood and Lynskey (1997) and Karsten and Moser (2009) …

Suppose the CPS [Current Population Survey] employee encountered one of the people designated as “unemployed” … and asked if she were “available for work”. What would her answer be? She knows with certainty that she will not be employed in the current period. Privately, she is delighted about this because the non-employed enjoy higher utility than the employed … Not only is she happy about not having to work, but the labor union also does not want her to work. From the perspective of the union, her non-employment is a fundamental component of the union’s strategy for promoting the welfare of its membership.

Lawrence J. Christiano

To me these kind of “New Keynesian” DSGE models, where unemployment is portrayed as a bliss, are a sign of a momentous failure to model real-world unemployment. It’s not only adding insult to injury — it’s also sad gibberish that shamelessly tries to whitewash neoliberal economic policies that put people out of work.

All empirical sciences use simplifying or unrealistic assumptions in their modeling activities. That is not the issue – as long as the assumptions made are not unrealistic in the wrong way or for the wrong reasons.

Theories are difficult to directly confront with reality. Economists therefore build models of their theories. Those models are representations that are directly examined and manipulated to indirectly say something about the target systems.

But models do not only face theory. They also have to look to the world. Being able to model a “credible” DSGE world — how credible that world is, when depicting unemployment as a “happy experience” and predicting the wage markup to increase with unemployment, I leave to the reader to decide — a world that somehow could be considered real or similar to the real world, is not the same as investigating the real world. Even though all theories are false, since they simplify, they may still possibly serve our pursuit of truth. But then they cannot be unrealistic or false in any way. The falsehood or unrealisticness has to be qualified.

The final court of appeal for macroeconomic models is the real world — and as long as no convincing justification is put forward for how the inferential bridging from models to reality de facto is made, macroeconomic model building is little more than “hand waving” that gives us rather little warrant for making inductive inferences from models to real world target systems. If substantive questions about the real world are being posed, it is the formalistic-mathematical representations utilized to analyze them that have to match reality, not the other way around.

On the non-neutrality of money

Paul Krugman has repeatedly over the years argued that we should continue to use neoclassical hobby horses like IS-LM and Aggregate Supply-Aggregate Demand models. Here’s one example:

So why do AS-AD? … We do want, somewhere along the way, to get across the notion of the self-correcting economy, the notion that in the long run, we may all be dead, but that we also have a tendency to return to full employment via price flexibility. Or to put it differently, you do want somehow to make clear the notion (which even fairly Keynesian guys like me share) that money is neutral in the long run.

I doubt that Keynes would have been impressed by having his theory being characterized with catchwords like “tendency to return to full employment” and “money is neutral in the long run.”

One of Keynes’s central tenets — in clear contradistinction to the beliefs of neoclassical economists — is that there is no strong automatic tendency for economies to move toward full employment levels in monetary economies.

Money doesn’t matter in neoclassical macroeconomic models. That’s true. But in the real world in which we happen to live, money does certainly matter. Money is not neutral and money matters in both the short run and the long run:

The theory which I desiderate would deal … with an economy in which money plays a part of its own and affects motives and decisions, and is, in short, one of the operative factors in the situation, so that the course of events cannot be predicted in either the long period or in the short, without a knowledge of the behaviour of money between the first state and the last. And it is this which we ought to mean when we speak of a monetary economy.

J. M. Keynes A monetary theory of production (1933)