Score Ten Predictions

Write down ten things you think will happen this month and assign each a probability between 10% and 90%. Examples: "My package arrives by Friday (80%)," "The team wins their game (60%)," "I finish the book I started (30%)."

At month's end, score yourself. Look at all predictions where you wrote 70%. If seven of ten came true, you are calibrated at that level. If all ten came true, you were underconfident. If four came true, you were overconfident.

Run this for three months and a pattern emerges: most people are systematically overconfident at the extremes. Seeing your own bias on paper is the fastest way to correct it.