Prosecutor's fallacy

Biological Parallel

DNA matching between crime scene and suspect (1 in 100,000 probability by chance) seems damning—the prosecutor's fallacy. But in cities of 8 million, 80 individuals match by chance alone. Cheetahs exhibit extreme genetic similarity (95%+ shared alleles from population bottleneck 10,000 years ago), yet individual identification still requires multiple genetic markers. The fallacy: presenting P(evidence|innocence is rare) while ignoring P(innocence|evidence) which depends critically on prior probability and population size. Forensic scientists overcame this through database searches and multiple markers; legal systems lag. Businesses commit identical errors: rare market timing (1 in 1,000 quarters) seems like skill until you consider 10,000 fund managers guarantee ten spurious winners by pure chance.