If you don't know where you are going, you can't tell if you have arrived: defining goals for drug safety announcements.

One of the responses available to drug regulators facing a potential drug safety issue is to release a "Dear Doctor" letter describing the problem. Although numerous such safety alerts are issued every year, we know almost nothing about their effectiveness in improving patient outcomes. The article by Reber et al. in this issue is important because it is one of the few studies to examine the effect of such safety alerts on physician behavior.