UFO Occurrence Base-Rate Simulator

Every "unexplained sighting report" gets weighed against two possible causes: a genuinely anomalous event, or an ordinary, misidentified one — aircraft, satellites, drones, lens flare, weather balloons. This simulator makes the base-rate fallacy visible: it simulates a large population of events, splits it into a tiny slice of genuine anomalies and a huge slice of mundane look-alikes, and lets each slice generate "reports" at its own rate. Because mundane events vastly outnumber genuine ones, even a very reliable reporting process ends up dominated by false positives from the mundane population — so the correct, Bayes'-theorem-derived posterior probability of a genuine anomaly stays far lower than the naive intuition based on reliability alone. Adjust the true base rate, the report reliability, and the false-positive rate to see exactly how each one moves the true answer.