Which English mathematician introduced the concept of regression to the mean?

Francis Galton introduced the concept of regression to the mean. He encountered the phenomenon while studying heredity, including the sizes of sweet-pea seeds and the heights of parents and children. Extremely large or small measurements tended, on average, to be followed by measurements closer to the population average.

Galton first called the idea “reversion” before the modern term regression became established. His work showed that exceptional results often partly reflect temporary or random influences, so repeating a measurement does not usually produce an equally extreme result. Regression to the mean is therefore a statistical pattern, not a force that actively pulls observations toward average values.

Galton’s investigations helped establish modern correlation and regression analysis. Karl Pearson later developed the mathematical treatment of correlation, and Ronald Fisher made major advances in statistical inference. A common mistake is to interpret regression to the mean as proof that an intervention caused improvement; without a suitable comparison, natural statistical fluctuation can be mistaken for treatment success.