Simpson's Paradox
A treatment does better for men, and better for women, and worse for people. None of the arithmetic is wrong.
1903 (Yule), 1951 (Simpson), 1972 (named)20 min read
British statistics
George Udny Yule
1871 – 1951
One of the founders of modern statistics, a student of Karl Pearson and later a lecturer at Cambridge. His 1903 paper on the association of attributes described the reversal effect now called Simpson's paradox two generations before Simpson, which is why some writers call it the Yule–Simpson effect.