Home > Uncategorized > ‘New Keynesian’ DSGE models

‘New Keynesian’ DSGE models

from Lars Syll

SR002_FRONTIn 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.

  1. January 29, 2016 at 2:46 am

    Apparently economists have no respect either for science or the things they supposedly study. Such models as you describe simply are unworkable in an interactive and emergent reality that is the world around us. Axiomatic and linear models as those described here and favored by economists are not only useless but actually impede our observations and understanding. A great deal more maturity on the part of economists is called for.

  2. January 29, 2016 at 8:43 am

    Really, Lars, I do not understand why you continue to discuss about these secondary hypothesis (separablity, etc.). Doing so, you “play the game”, give credibility to the model and make people forget it main hypothesis : its “solution” is given by the maximisation of a function, whatever it is (Euler’s conditon) A pure non sense.

    • January 29, 2016 at 9:32 am

      The reason I choose not only to give an ‘external’ critique is that — as Gunnar Myrdal argued already back in the 1930s– an ‘immanent critique’ often is more powerful (showing that even given the theory’s own presuppositions it is defective). And I guess I have not completely given up on trying to communicate with the people I criticise …

  3. January 29, 2016 at 9:13 pm

    Economists have forgotten the meaning of argument. Economics became a substitute religion that only knows how to pontificate, said Ulrike Herrmann, economics editor of Tageszeitung daily newspaper,



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