A Structural Perspective on the Experimentalist School

What has always bothered me about the "experimentalist" school is the false sense of certainty it conveys. My view, like Leamer's, is that there is no way to escape the role of assumptions in statistical work, so our conclusions will always be contingent. Hence, we should be circumspect about our degree of knowledge. I present some lessons for economics from the field of marketing, a field where broad consensus has been reached on many key issues over the past twenty years. In marketing, 1) the structural paradigm is dominant, 2) the data are a lot better than in some fields of economics, and 3) there is great emphasis on external validation. Of course, good data always helps. I emphasize that the ability to do controlled experiments does not obviate the need for theory, and finally I address different approaches to model validation.