Forecaster Calibration Simulator

Every time a forecaster says "I'm 90% confident," they're making a testable claim: across every occasion they say that, they should turn out right about 9 times in 10 — no more, no less. This simulator generates a long stream of probabilistic predictions from a single forecaster whose honesty you control with the overconfidence bias slider, resolves each one against its true probability, and plots the results as a scatter of individual calls alongside a binned calibration curve. Compare that curve to the diagonal "perfect calibration" reference line and watch the Brier score and expected calibration error (ECE) quantify exactly how much a forecaster's confidence outruns their accuracy — the same diagnostic tools used to evaluate real-world forecasting tournaments.