This paper argues that formal empirical work which, to use Sargent's (1987, p. 7) phrase, tries to "take models seriously econometrically" has had almost no influence on serious thinking about substantive as opposed to methodological questions. Instead, the only empirical research that has influenced thinking about substantive questions has been based on methodological principles directly opposed to those that have become fashionable in recent years. Successful empirical research has been characterized by attempts to gauge the strength of associations rather than to estimate structural parameters, verbal characterizations of how causal relations might operate rather than explicit mathematical models, and the skillful use of carefully chosen natural experiments rather than sophisticated statistical technique to achieve identification.
These views may seem extreme. But I invite the reader to try and identify a single instance in which a "deep structural parameter" has been estimated in a way that has affected the profession's beliefs about the nature of preferences or production technologies or to identify a meaningful hypothesis about economic behavior that has fallen into disrepute because of a formal statistical test.
--Larry Summers, "The Scientific Illusion in Empirical Macroeconomics," Scandinavian Journal of Economics (1991), laying the smack down