What is a good model in economics? The History of Economics Playground at the Institute for New Economic Thinking asked a dozen economists in the halls of the Mount Washington Hotel in Bretton Woods.

Good models are those that pass the test of time, says Philippe Aghion. Brad DeLong presents what has come to be called Friedman's "F-Twist": assumptions don't matter -- a good model is one that predicts well. Wrong, says Anatole Kaletsky, economists ought to model the whole range of human behavior, and doing so requires re-examining the very assumptions on which our models rest. And to George Akerlof, a good model applies to the specific question asked; it corresponds to the problem at hand.

Yves Smith over at Naked Capitalism has a few things to say about all this:

Mainstream economics fetishizes the use of models. Even if your insight could be stated clearly and concisely in a narrative, it is not economics unless a model is involved. For instance, two of our colleagues have gone through Mankiw’s introductory economics textbook and have ascertained that every use of a graph is not only unnecessary, but in most cases serves to impede rather than add to the presentation of the concept under discussion.

The preoccupation with models suggests that the economics discipline has unduly limited its problem-solving abilities by giving high priority to “models”.