First, encouragingly for us nerds, it did help to have some training—of a particular kind. Just an hour of training in basic statistics improved the performance of forecasters by helping them turn their expertise about the world into a sensible probabilistic forecast, such as “The chance that a woman will be elected president of the United States within the next ten years is 25 percent.” The tip that seemed to help most was to encourage them to focus on something called “base rates.”13
