This entry contributed by Margherita Barile

British mathematician and biologist who invented revolutionary techniques for applying statistics to natural sciences. In particular, he discovered methods to optimize the evaluation of empirical results. Among his many important discoveries were the analysis of variance technique (ANOVA ) which demonstrates how a restricted number of experiments can be sufficient to devise general laws considering several variables at the same tim, extreme value theory which shows how to predict the most severe possible form of an accident or catastrophe based on past occurrences, and the P-value which serves as a rigorous numerical measure of the reliability of a data sample as a source of scientific predictions.

Fisher's prolific findings profited from his work at an agricultural research center, and even from a physical inability that he bore throughout his life: his near-blindness that kept him away from the military during the First World War and forced him to focus his inquiry on abstract speculation. His intuition anticipated various later achievements of science, from the classification of blood groups to the statistical analysis of texts for the purpose of philological investigation.

The general principles of Fisher's theory are exposed in his book Statistical Methods for Research Workers, whereas his work The Genetical Theory of Natural Selection presents a mathematical treatment of evolution. In the latter, he proved that even small differences could produce significant changes in the history of species. He devoted himself to genetical studies in the last part of his brilliant academic career, which had started in 1929 with his election to the Royal Society. He held the Balfour Chair of Genetics at Cambridge from 1943 to 1957, the year of his retirement.