Extinction Date Estimation from Sighting Records // Estimates the historic date of extinction of a species from a time-ordered record of sighting events. Given a table of sighting counts per year, computes extinction date estimators from the sighting- record literature: optimal linear estimation under a record- value model (Roberts Solow, 2003), nonparametric and sighting- effort-weighted persistence tests (Solow, 1993; Solow, 2005), a sighting-rate persistence test comparable across records with different observation periods (McInerny, Roberts, Davy Cribb, 2006), a classical confidence interval on the end of a temporal range (Strauss Sadler, 1989), a truncation-point extrapolation (Robson Whitlock, 1964), and a combinatorial persistence test based on inclusion-exclusion over sighting-gap occupancy (Burgman, Grimson Ferson, 1995). Every estimator is built on a single validated input object and returns a common result class with, where defined, a point estimate, a confidence interval, or a full persistence-probability curve.