 It would seem that this interpretation would render Friedman’s views inconsistent, because in testing whether firms attempt to maximize profits, one is checking whether predictions of theory concerning the behavior of firms are true or false. An “assumption” such as “firms maximize profits” is itself a prediction. But there is a further wrinkle. Friedman is not concerned with every prediction of economic theories. In Friedman’s view, “theory is to be judged by its predictive power exclusively for the class of phenomena which it is intended to explain” (1953, p. 8 [italics added]). Economists are interested in only some of the implications of economic theories. Other predictions, such as those concerning the results of surveys of managers, are irrelevant to policy. What matters is whether economic theories are successful at predicting the phenomena that economists are interested in. In other words, Friedman believes that economic theories should be appraised in terms of their predictions concerning prices and quantities exchanged on markets. In his view, what matters is “narrow predictive success” (Hausman 2008a), not overall predictive adequacy.