Regression Toward the Mean

Discovered by Francis Galton in the 1880s while studying the heights of parents and children. He found that exceptionally tall parents tend to have children closer to average height — and vice versa. Galton called this “regression towards mediocrity.” The insight extends far beyond heredity: a record-breaking sports season is typically followed by a more ordinary one, not because of decline, but because extreme outcomes include a large dose of luck.