The large literature on the impact of advertising on consumers and firm behavior in marketing and economics has tried to distinguish between the informative and the persuasive roles of advertising. The extant literature typically uses advertising expenditure and implicitly assumes that...

In collaboration with three companies selling a diverse set of products, we conducted randomized field experiments in which experimentally tailored email ads were sent to millions of individuals. We found consistently that personalizing the emails by adding consumer-specific information (e.g.,...