• Statistician and Geneticist Ronald Aylmer Fisher, 1890
  

Fisher was born in East Finchley in London, England, to George and Katie Fisher. His father was a successful fine arts dealer at one time. He had a happy childhood, being doted on by three older sisters, an older brother, and his mother, but she died when he was 14. His father lost his business in several ill considered transactions only 18 months later, according to the biography by Fisher's daughter, Joan. Joan Fisher's biography is the main source of information on her father's early life; it was published under her married name and with the statistical advice of her husband, George E. P. Box.

Although Ronald Fisher had quite poor eyesight, he was a precocious student, winning the Neeld Medal (a competitive essay in mathematics) at Harrow School at the age of 16. Because of his poor eyesight, he was tutored in mathematics without the aid of paper and pen, which developed his ability to visualize problems in geometrical terms, without contributing to his interest in writing proper derivations of mathematical solutions, especially proofs. He amazed his peers with his ability to conjecture mathematical solutions without justifying his conclusions by showing intermediate steps. He also developed a strong interest in biology, and especially evolutionary biology.

In 1909, he won a scholarship to the Gonville and Caius College, Cambridge. There he formed many friendships and became enthralled with the heady intellectual atmosphere. At Cambridge, Fisher learned of the newly rediscovered theory of Mendelian genetics. He saw biometry and its growing corpus of statistical methods as a potential way to reconcile the discontinuous nature of Mendelian inheritance with continuous variation and gradual evolution. However, his foremost concern was eugenics, which he saw as a pressing social as well as scientific issue that encompassed both genetics and statistics.

In 1911, Fisher was involved in the forming of the University of Cambridge Eugenics Society with John Maynard Keynes, R.C. Punnett, and Horace Darwin (the son of Charles Darwin). This group was active, and it held monthly meetings, often featuring addresses by leaders of mainstream eugenics organizations, such as the Eugenics Education Society of London, founded by Charles Darwin's half - cousin, Francis Galton in 1909.

Close to Fisher's graduation in 1912, his tutor told his student that — despite his enormous aptitude for scientific work and his mathematical potential — his disinclination to show calculations or to prove propositions rendered him unsuited for a career in applied mathematics, which required greater fortitude. His tutor gave him a "lukewarm" recommendation, stating that if Fisher "had stuck to the ropes he would have made a first - class mathematician, but he would not."

After his graduation, Fisher was eager to join the British Army in anticipation of the entry of Great Britain into World War I. However, he failed the medical examinations (repeatedly) because of his poor eyesight. Over the next six years, he worked as a statistician for the City of London. For part of his war work, he took up teaching physics and mathematics at a sequence of public schools, including the Bradfield College in Berkshire, as well as aboard the H.M. Training Ship Worcester. Major Leonard Darwin (another of son of Charles Darwin) and an unconventional and vivacious friend he called Gudruna were almost his only contacts with his Cambridge circle. They sustained him through this difficult period.

A bright spot in his life then was that Gudruna set him up with her sister Eileen Guinness. They were married in 1917 when she was only 17 years old. With her sister's help, he set up a subsistence farming operation on the Bradfield estate, where they had a large garden and raised animals, learning to make do on very little. They lived through the rest of the war without using their food coupons.

During this period, Fisher started writing book reviews for the Eugenic Review and gradually increased his interest in genetic and statistical work. He volunteered to undertake all such reviews for the journal, and was hired to a part time position by Major Darwin. He published several articles on biometry during this period, including the ground - breaking paper "The Correlation Between Relatives on the Supposition of Mendelian Inheritance", written in 1916 and published in 1918. This paper laid foundation for what came to be known as biometrical genetics, and it introduced the methodology of the analysis of variance, which was a considerable advance over the correlation methods used earlier. This paper showed that the inheritance of traits measurable by real values (i.e., continuous or dimensional traits) is consistent with Mendelian principles. This forms the basis of the genetics of complex trait inheritance and mitigated debates between biometricians and Mendelians, and the compatibility of particulate inheritance with natural selection. In this paper was also the first use of the term "variance" in statistics.

After the end of World War I, Fisher went looking for a new job in low hopes, calling himself "an egregious failure in two professions" as a commercial statistician and as a teacher. He was offered a position at the Galton Laboratory led by Karl Pearson, the founder of mathematical statistics in Great Britain. Because he saw the developing rivalry with Pearson as a professional obstacle, however, he accepted a temporary job instead as a statistician with a small agricultural station in the countryside in 1919.

In 1919, Fisher started work at Rothamsted Experimental Station in Harpenden, Hertfordshire, England. Here he started a major study of the extensive collections of data recorded over many years. This resulted in a series of reports under the general title Studies in Crop Variation. This began a period of great productivity. Over the next seven years, he pioneered the principles of the design of experiments and elaborated his studies of analysis of variance. He furthered his studies of the statistics of small samples. Perhaps even more important, he began his systematic approach of the analysis of real data as the springboard for the development of new statistical methods. He developed computational algorithms for analyzing data from his balanced experimental designs. In 1925, this work resulted in the publication of his first book, Statistical Methods for Research Workers. This book went through many editions and translations in later years, and it became the standard reference work for scientists in many disciplines.

In 1935, this book was followed by The Design of Experiments, which was also widely used. According to Conniffe,

Ronald A. Fisher was "interested in application and in the popularization of statistical methods and his early book Statistical Methods for Research Workers, published in 1925, went through many editions and motivated and influenced the practical use of statistics in many fields of study. His Design of Experiments (1935) [promoted] statistical technique and application. In that book he emphasized examples and how to design experiments systematically from a statistical point of view. The mathematical justification of the methods described was not stressed, and its proofs were often barely sketched out or omitted altogether ..., a fact which led H. B. Mann to fill in the gaps with a rigorous mathematical treatment in his well - known treatise, Mann (1949)."

In addition to analysis of variance, Fisher named and promoted the method of maximum likelihood estimation. Fisher also originated the concepts of sufficiency, ancillary statistics, Fisher's linear discriminator and Fisher information. His article On a distribution yielding the error functions of several well known statistics (1924) presented Pearson's chi - squared test and William Gosset's t in the same framework as the Gaussian distribution, and his own parameter in the analysis of variance Fisher's z-distribution (more commonly used decades later in the form of the F distribution). These contributions made him a major figure in 20th century statistics.

In defending the use of the z distribution when the data were not Gaussian, Fisher used a "randomization test" for data from randomized experiments. Randomization had previously been used by Charles Sanders Peirce.

According to biographers Frank Yates and Mather, "Fisher introduced the randomization test, comparing the value of t or z actually obtained with the distribution of the t or z values when all possible random arrangements were imposed on the experimental data." In the randomization test, the random arrangements considered were those arising from the design specified in the treatment protocol. When similar tests are used on data from nonrandomized studies, the tests are called permutation tests of significance. Fisher wrote that permutation tests were "in no sense put forward to supersede the common and expeditious tests based on the Gaussian theory of errors."

His work on the theory of population genetics also made him one of the three great figures of that field, together with Sewall Wright and J.B.S. Haldane, and as such was one of the founders of the neo - Darwinian modern evolutionary synthesis. In addition to founding modern quantitative genetics with his 1918 paper, he was the first to use diffusion equations to attempt to calculate the distribution of gene frequencies among populations. He pioneered the estimation of genetic linkage and gene frequencies by maximum likelihood methods, and wrote early papers on the wave of advance of advantageous genes and on clines of gene frequency. His 1950 paper on gene frequency clines is notable as the first application of a computer, the EDSAC, to biology.

Fisher had a long and successful collaboration with E.B. Ford in the field of ecological genetics. The outcome of this work was the general recognition that the force of natural selection was often much stronger than had been appreciated before, and that many ecogenetic situations (such as polymorphism) were not selectively neutral, but were maintained by the force of selection. Fisher was the original author of the idea of heterozygote advantage, which was later found to play a frequent role in genetic polymorphism. The discovery of indisputable cases of natural selection in nature was one of the main strands in the modern evolutionary synthesis.

Fisher introduced the concept of Fisher information in 1925. Interest in Fisher information was rekindled by B. Roy Frieden's book Physics from Fisher Information (1998), which attempts to derive the laws of physics from a Fisherian starting point.

Fisher was an ardent promoter of eugenics, which also stimulated and guided much of his work in the genetics of humans. His book The Genetical Theory of Natural Selection was started in 1928 and published in 1930. It contained a summary of what was already known in the literature. He developed ideas on sexual selection, mimicry and the evolution of dominance. He famously showed that the probability of a mutation increasing the fitness of an organism decreases proportionately with the magnitude of the mutation. He also proved that larger populations carry more variation so that they have a larger chance of survival. He set forth the foundations of what was to become known as population genetics.

About a third of the book concerned the applications of these ideas to humans, and presented the data available at that time. He presented a theory that attributed the decline and fall of civilizations to its arrival at a state where the fertility of the upper classes is forced down. Using the census data of 1911 for Britain, he showed that there was an inverse relationship between fertility and social class. This was partly due, he believed, to the rise in social status of families who were not capable of producing many children but who rose because of the financial advantage of having a small number of children. Therefore he proposed the abolition of the economic advantage of small families by instituting subsidies (he called them allowances) to families with larger numbers of children, with the allowances proportional to the earnings of the father. He himself had two sons and six daughters. According to Yates and Mather, "His large family, in particular, reared in conditions of great financial stringency, was a personal expression of his genetic and evolutionary convictions."

The book was reviewed, among others, by physicist Charles Galton Darwin, a grandson of Charles Darwin's, and following publication of his review, C.G. Darwin sent Fisher his copy of the book, with notes in the margin. The marginal notes became the food for a correspondence running at least three years. Fisher's book also had a major influence on the evolutionary biologist W.D. Hamilton and the development of his later theories on the genetic basis for the existence of kin selection.

Between 1929 and 1934 the Eugenics Society also campaigned hard for a law permitting sterilization on eugenic grounds. They believed that it should be entirely voluntary, and a right, not a punishment. They published a draft of a proposed bill, and it was submitted to Parliament. Although it was defeated by a 2:1 ratio, this was viewed as progress, and the campaign continued. Fisher played a major role in this movement, and served in several official committees to promote it.

In 1934, Fisher moved to increase the power of scientists within the Eugenics Society, but was ultimately thwarted by members with an environmentalist point of view, and he, along with many other scientists, resigned.

The interest in eugenics, and his experiences working on the Canadian farm, made Fisher interested in starting a farm of his own. In these plans he was encouraged by Gudruna, the wife of a college friend, and this led to his meeting Ruth Eileen Grattan Guinness, Gudruna's younger sister. Their father, Dr Henry Grattan Guinness, had died when they were young. Ruth Eileen was only sixteen years of age when she met Fisher. She knew that her mother would not approve of her marrying so young. As a result Fisher married Ruth Eileen at a secret wedding ceremony without her mother's knowledge, on 26 April 1917, only days after Ruth Eileen's 17th birthday. They had two sons and seven daughters, one of whom died in infancy. His daughter Joan married George E.P. Box and wrote a biography of her father that celebrated his scientific achievements and frankly exposed his personality flaws, while suffering from partisanship in championing Fisher's role in statistics, often just paraphrasing passages from Fisher or from George E.P. Box.

As an adult, Fisher was noted for his loyalty to his friends. Once he had formed a favorable opinion of any man, he was loyal to a fault. A similar sense of loyalty bound him to his culture. He was a patriot, a member of the Church of England, politically conservative, and a scientific rationalist. Much sought after as a brilliant conversationalist and dinner companion, he very early on developed a reputation for carelessness in his dress and, sometimes, his manners. In later years he was the archetype of the absent-minded professor.

He knew the scriptures well and H. Allen Orr describes him as "deeply devout Anglican who, between founding modern statistics and population genetics, penned articles for church magazines" in the Boston Review. But he was not dogmatic in his religious beliefs. In a 1955 broadcast on Science and Christianity, he said:

The custom of making abstract dogmatic assertions is not, certainly, derived from the teaching of Jesus, but has been a widespread weakness among religious teachers in subsequent centuries. I do not think that the word for the Christian virtue of faith should be prostituted to mean the credulous acceptance of all such piously intended assertions. Much self - deception in the young believer is needed to convince himself that he knows that of which in reality he knows himself to be ignorant. That surely is hypocrisy, against which we have been most conspicuously warned.

Some think that it was first Fisher who referred to the growth rate r (used in equations such as the logistic function) as the Malthusian parameter, as a criticism of the writings of Thomas Robert Malthus, who Fisher referred to "... a relic of creationist philosophy ..." in observing the fecundity of nature and deducing (as Darwin did) that this therefore drove natural selection.

However, it is much more likely that Fisher called r the Malthusian parameter because in 1798 Malthus had published An Essay on the Principal of Population, which contained a mathematical model of population growth that became commonly known as the Malthusian Growth Model and which contained said parameter in the following formula:

where P₀ = initial population, r = growth rate, t = time.

Fisher received the recognition of his peers in 1929 when he was inducted into the Royal Society. His fame grew and he began to travel more and lecture to wider circles. In 1931, he spent six weeks at the Statistical Laboratory at Iowa State College in Ames, Iowa. He gave three lectures per week on his work, and he met many of the active American statisticians, including George W. Snedecor. He returned to Iowa State again for another visit in 1936.

In 1933 he left Rothamsted to become a Professor of Eugenics at the University College London. In 1937, he visited the Indian Statistical Institute in Calcutta, which at the time consisted of one part time employee, P. C. Mahalanobis. He visited there often in later years, encouraging its development. He was the guest of honor at its 25th anniversary in 1957 when it had grown to 2000 employees.

In 1939, when World War II broke out for the British Empire, the University tried to dissolve the eugenics department, and it ordered all of the animals destroyed. Fisher fought back, but then he was dispatched back to Rothamsted with a much reduced staff and resources. He was unable to find any really suitable war work, and though he kept very busy with various small projects, he became discouraged of any real progress. His marriage disintegrated. His oldest son George, an aviator, was killed in combat.

In 1943, Fisher was offered the Balfour Chair of Genetics at the University of Cambridge, his alma mater. During the war, this department was almost destroyed, but the University promised him that he would be charged with rebuilding it after the war. Fisher accepted this offer, but the promises were largely unfilled, and the department grew very slowly. A notable exception was the recruitment in 1948 of the Italian researcher Cavalli - Sforza, who established a one - man unit of bacterial genetics. He continued his work on mouse chromosome mapping — breeding the mice in laboratories in his own house — and other projects. These culminated in the publication in 1949 of The Theory of Inbreeding. In 1947, Fisher co - founded the journal Heredity: An International Journal of Genetics with Cyril Darlington.

Fisher became a prominent opponent of Bayesian statistics, and was even the first to use the term "Bayesian". He was in particular critical of the idea of prior probability, a statistical inference applied to a set of data before new data is added (by observation).

Ronald Fisher was opposed to the UNESCO Statement of Race. He believed that evidence and everyday experience showed that human groups differ profoundly "in their innate capacity for intellectual and emotional development" and concluded that the "practical international problem is that of learning to share the resources of this planet amicably with persons of materially different nature", and that "this problem is being obscured by entirely well intentioned efforts to minimize the real differences that exist". The revised statement titled "The Race Concept: Results of an Inquiry" (1951) was accompanied by Fisher's dissenting commentary.

Fisher eventually received many awards for his work, and he was dubbed a Knight Bachelor by Queen Elizabeth II in 1952.

Fisher was opposed to the conclusions of Richard Doll and Austin B. Hill that smoking causes lung cancer. He compared the correlations in their papers to a correlation between the import of apples and the rise of divorce in order to show that correlation does not imply causation.

To quote Yates and Mather again, "It has been suggested that the fact that Fisher was employed as consultant by the tobacco firms in this controversy casts doubt on the value of his arguments. This is to misjudge the man. He was not above accepting financial reward for his labors, but the reason for his interest was undoubtedly his dislike and mistrust of puritanical tendencies of all kinds; and perhaps also the personal solace he had always found in tobacco."

After retiring from the University of Cambridge in 1957, Fisher emigrated, and he spent some time as a senior research fellow at the Australian CSIRO in Adelaide, South Australia. He died and was buried in Adelaide in 1962.

Fisher was awarded the Linnean Society of London's prestigious Darwin – Wallace Medal in 1958.

Fisher's important contributions to both genetics and statistics are emphasized by the remark of L.J. Savage, "I occasionally meet geneticists who ask me whether it is true that the great geneticist R.A. Fisher was also an important statistician." (Annals of Statistics, 1976).