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A blind spot in economics? Accepting unsupported claims about reality

Fri, 18 Nov 2011 04:58:00 GMT

A very big H/T to Physics of Finance blog for bringing this paper to my attention, and for providing some commentary.

I would like to point everyone to a fascinating recent analysis of economists' opinions about the scientific method (that seems the best term for it, at least). Ole Rogeberg, a reader of this blog, alerted me to some work by himself and Hans Melberg in which they surveyed economists to see how much they looked to actual empirical tests of a theory's predictions in judging the value of a theory. The answer, it turns out, is -- not much. Internal consistency seems to be more important than empirical test.

This even for a theory -- the theory of "rational addiction", which seeks to explain heroin addiction and other life destroying addictions as the consequence of fully rational choices on the part of individuals as they maximize their expected utility over their lifetimes -- which on the face of it seems highly unlikely, making the burden of empirical evidence (one would think) even higher. Some history. Gary Becker (Nobel Prize) of the University of Chicago is famous for his efforts to push the neo-classical framework into every last corner of human life. He (and many followers) have applied the trusted old recipe of utility maximization to understand (they claim) everything from crime to patterns of having children to addiction. You may see a slobbering shivering drunk or junkie in an alleyway in winter and think -- like most people -- there goes someone trapped in some very destructive behavioural feedback controlled by the interaction of addictive physical substances, emotions and so on. Not Becker. It's all quite rational, he argues.

The paper now appears in our ever-growing research library and you can download it from here,

Ole Rogeberg, Hans Olav Melberg


Do economists accept absurd and unsupported claims about reality, and if so, why? We define four types of claims commonly made in economics that require different types of evidence, and show examples of each from the rational addiction literature. Claims about real world causal mechanisms and welfare effects seem poorly supported. A survey mailed to all researchers with peer-reviewed work on rational addiction theory provides some evidence that criteria for evaluating claims of pure theory and statistical prediction are better understood than those needed for claims of causality or welfare analysis. We suggest that unsupported claims about real world causality or welfare may be accepted in parts of economics provided they derive from a formally correct model consistent with certain types of (often aggregate) data. The rational addiction literature illustrates that this can lead to absurd and unjustified claims being made and accepted in even highly-ranked journals.

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