Risk Literacy

A brief step-by-step online tutorial can teach people how to accurately calculate and compare the event rates of two risks (e.g., case-fatality rates for the flu versus COVID-19) by illustrating how to divide the number of key events (e.g., number of deaths among people infected with disease X) by the total number of events (e.g., total number of people infected with disease X).

A fact box is a tabular summary of the best available evidence about the benefits and harms of a medical procedure, medical treatment, or health behavior.

Unlike conditional probabilities, natural frequencies are not normalized with respect to the base rates. They therefore make it easier for people to apply Bayes’s rule to determine, for instance, how likely it is that a person who tests positive for breast cancer does, in fact, have the disease (i.e., the posterior probability of the disease given a positive test result).

Knowing how to construct natural frequency trees out of probability information helps people successfully make Bayesian inferences (e.g., to understand what a positive test result really means).