A micromort, a unit for comparing and communicating risk to patients, is equivalent to a one-in-a-million chance of dying. Hundreds of millions of operations are performed every year, and the risk of death is typically around half a percent, to which patients might say things like, “I could die just as easily crossing the road,” making it clear they really don’t understand the difference in magnitude of risk. One way to communicate risk is by analogy. For example, just going under anesthesia carries about a 1-in-100,000 chance you won’t wake up. How much is that? Well, that’s about the same ri...