The risks associated with medicines and medical procedures are rarely conveyed clearly. I remember learning about intra-uterine devices in high school health class and the fact that uterine puncture was a risk with them, which sounds awful and terrifying. However, there are two vital pieces of information omitted in that statement: first, how high is the risk? 1 in 1,000 is very different from 1 in 1,000,000. Second, what are the consequences? “Antibiotics and possible hospitalization” is very different from “hysterectomy and possible death.”

You can turn this lack of clarity to your advantage if you are an evil marketer, pitching either in favor of or against the product. Here’s an exercise:

Suppose a medication for condition X has the side effect of raising a person’s risk for disease Y. On average, the risk increases from a 1% chance to a 3% chance. Represent this data in a way that
a) makes it seem like a terrible side effect,
b) makes it look like a completely dismissible side effect, and
c) gives full disclosure on the risk.