Ronald Aylmer Fisher | Biography

Sir Ronald Aylmer Fisher formalized and extended the field of statistics and revolutionized the concept of experimental design. He worked for 14 years as a research statistician and later held professorships in genetics, another field to which he made significant contributions. Fisher wrote about 300 papers and seven books during his prodigious career.

The youngest of seven children, Ronald Fisher was born on February 17, 1890, in a northern suburb of London. His father, George Fisher, was a partner in a fine arts auction firm. Because of poor eyesight, the young Fisher was not allowed to read or write under artificial light. Consequently, he rarely took notes at lectures he attended, and he preferred to solve problems mentally rather than on paper. He developed a facility for visualizing complex geometrical relationships in his mind. This ability later proved fruitful, as his geometrical interpretation of statistics led him to previously unattainable results.

In 1909, Fisher earned a scholarship to attend Gonville and Caius College in Cambridge, where he specialized in mathematics and theoretical physics while also studying genetics. He graduated in 1912. For the next six years, Fisher searched for the right type of occupation, even working briefly as a farm laborer in Canada. Primarily, however, he worked as a statistician for the Mercantile and General Investment Company in London (1913 to 1915) and as a public school teacher (1915 to 1919). He was unhappy and, apparently, ineffective as a teacher--throughout his career, he was recognized as a brilliant thinker who had difficulty explaining his ideas to others. In 1917, he married Ruth Eileen Guinness; they had eight children and eventually separated.

Even though his jobs did not support research, Fisher published several papers during this period. One of his earliest accomplishments in statistics was determining the distribution of the correlation coefficient in normal samples, a problem he solved by formulating it in terms of n-dimensional Euclidean space with n representing the sample size. He wrote two papers on eugenics (the science of improving the human race through selective mating); his concern that the less talented lower classes produced offspring at a faster rate than the more capable upper classes influenced his personal choice to have a large family.

Because of his growing reputation as a mathematician, in 1919 Fisher was offered a job analyzing a 66-year accumulation of statistical data at the Rothamsted Experimental Station, an agricultural research laboratory about 25 miles north of London. For the next 14 years, Fisher took advantage of the huge data resources at Rothamsted to derive new analysis techniques as well as agricultural results. He formulated the analysis of variance, which is now a fundamental tool of statistical analysis; it isolates the effects of several variables in an experiment, showing what contribution each made to the results. Consequently, he advocated factorial experimentation (in which several factors can vary simultaneously) rather than attempting to vary only one factor at a time. This not only speeds results by gathering information on the effects of several variables at one time, but it also allows investigation of interactions of variables that differ from any of the variables acting alone.

In another innovation of experimental design, Fisher advocated random arrangement of samples receiving different treatments. Traditional agricultural experiments arranged samples according to elaborate placement schemes on checkerboard plots in an attempt to avoid bias from extraneous factors such as variations in soil and exposure to weather. Fisher demonstrated that by assigning these positions randomly, rather than according to a systematic pattern, facilitated statistical analysis of the results. His 1925 textbook, Statistical Methods for Research Workers, is considered a landmark work in the field. Unfortunately, it is so difficult to read that Fisher's friend and colleague M. G. Kendall wrote in Studies in the History of Statistics and Probability, "Somebody once said that no student should attempt to read it unless he had read it before."

During the course of his career, Fisher's theoretical work also included improvements to the Helmert-Pearson 2 distribution (including the addition of degrees of freedom) and the Student's t distribution, and development of what would eventually be called the F-distribution in his honor. He introduced the concept of the "null hypothesis" and developed procedures for decision-making based on the percentage difference between experimental results and the null hypothesis. He derived the distributions of numerous statistical functions including partial and multiple correlation coefficients and the regression coefficient, and he clarified the concept of the maximum likelihood estimate.

Fisher became a Fellow of the Royal Society in 1929, the same year he published a paper on sampling moments that would provide the foundation for future development of that topic. During the 1930s, he wrote several substantial papers on the logic of inductive inference.

Fisher left Rothamsted in 1933 to occupy the Galton Chair of Eugenics at University College in London, only to return during World War II when his department was evacuated to the Experimental Station. In 1935, he established a blood-typing department in the Galton Laboratory, which developed important information on Rh factor inheritance. That same year, he published Design of Experiments, another landmark text in statistical science. The following year, he published his first paper on discriminant analysis, which is now used in such areas as weather forecasting, medical research, and educational testing. During summer lectureships at Iowa State College's agricultural research center at Ames in 1931 and 1936, Fisher established contacts that helped popularize his techniques among American educators and psychologists as well as agriculturalists.

In 1943, Fisher joined the University of Cambridge as Balfour Professor of Genetics. He was knighted in 1952, and served as president of the Royal Society from 1952 until 1954. Both the Royal Society and the Royal Statistical Society awarded him several prestigious medals during his tenure at the University of Cambridge. In 1950, Fisher published Contributions to Mathematical Statistics, an annotated collection of 43 of his most significant papers, many of which had originally appeared in rather obscure journals. He formally retired in 1957, but continued working until a successor was found in 1959.

When Fisher left Cambridge in 1959, he moved to Adelaide, Australia, to join several of his former students and work as a statistical researcher for the Commonwealth Scientific and Industrial Research Organization. He died on July 29, 1962, as a result of an embolism following an intestinal disorder.