Q. I’m not influenced by all these gifts anyway, so what’s the problem?
A. Doctors, like everyone else, are influenced by promotion. Though there have been no randomized trials, there have been plenty of observational studies, and all of them have reached a similar conclusion (see Wazana): Doctors' prescribing behavior as well as other behaviors (for example, requests to the hospital formulary) are influenced by promotions and interactions with reps. Doctors who practice on the basis of promotion, meet with reps, and use information provided by them are more likely to prescribe more expensive, inappropriate medication. Though the possibility of publication bias exists, no study has shown that practicing on the basis of promotion leads to more cost-effective prescribing. And while no study has looked at the influence of gifts, or small gifts, per se, it is reasonable to extrapolate the vast social science literature on gifts (see below) to physicians. Though many physicians may believe otherwise, there is no reason to think that they are immune.