Is Advertising Informative? Evidence from Contraindicated Drug Prescriptions∗

Crestor, an important but controversial cholesterol-lowering drug, is contraindicated for use by senior and Asian patients. In this paper, we exploit this fact and a unique doctor-level prescription and advertising exposure data for statin drugs to examine the hypothesis of informative advertising. Our tests are based on the intuition that, if advertising is informative, it should lead to fewer contraindicated matches: Doctors should prescribe the drug less frequently to patients with characteristics for which the drug is contraindicated. We find strong evidence for the informative-advertising hypothesis: The match quality signaled by doctor-level advertising for contraindicated patients is significantly inferior to that signaled for the other patients. Our results are robust to the potential endogeneity in doctor-level advertising.