A micromort as a unit of comparing and communicating risk to patients 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 a half a percent, to which patients might say things like, “I could just die 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 anesthetic carries about a 1 in 100,000 chance you won’t wake up. How much is that? Well, that’s about the same risk as an expert sky dive. Okay, but that still may be kind of hard to wrap your head around. It’s hard to think in terms of small numbers. Imagine discussing a 0.0017 mile x 0.00227 mile rug. How big even is that? We need more digestible units. Enter the micromort as a unit of comparing and communicating risk to patients….