marketing also supports the claim that marketing benefits patients . An Uncertain Diagnosis

tives have incentives to “oversell” their products. But they also benefit by providing truthful information about their drugs’ benefits. In analyzing the effects of sales and promotion efforts, it is important to consider both the positive and negative aspects of drug marketing. There is a substantial literature in medical journals examining the marketing and promotional efforts of pharmaceutical firms. This literature is generally critical of those efforts, focusing on the negative aspects of promotion. Although the literature is expressed in empirical and scientific terms and makes use of data, it suffers from some weaknesses. If the same methods and level of rigor were used in analyzing another problem in medicine—say, the effectiveness of a particular remedy—scientific journals would reject the research and the Food and Drug Administration would not approve the remedy. All studies of the effects of pharmaceutical marketing have essentially the same format: Some group of physicians is the population under study. The physicians interact in some way with pharmaceutical salespeople. Some physician behavior with respect to pharmaceuticals is examined, and it is found to change following the interaction. The researchers then allege that the change demonstrates harmful behavior by the pharmaceutical company and the researchers call for some sort of reform, such as a strengthened code of ethics. There are three difficulties with this mode of analysis. First, the physician population subject to study is not randomly selected—it seems at least plausible that physicians who attend pharmaceutical sales pitches may want to change their current prescribing behavior, so research indicating a change is not all that surprising and should not be considered worrisome. Second, the literature has examined the effects of promotion mostly in circumstances in which promotion can lead only to harmful outcomes, but it is at least plausible that promotion could have beneficial outcomes by making physicians aware of new treatments. The third problem is more fundamental: The sur-