Sir Ronald Aylmer Fisher (17 February 1890
– 29 July 1962) was a British statistician
and geneticist. For his work in statistics,
he has been described as "a genius who almost
single-handedly created the foundations for
modern statistical science" and "the single
most important figure in 20th century statistics".
In genetics, his work used mathematics to
combine Mendelian genetics and natural selection;
this contributed to the revival of Darwinism
in the early 20th-century revision of the
theory of evolution known as the modern synthesis.
For his contributions to biology, Fisher has
been called "the greatest of Darwin’s successors".From
1919 onward, he worked at the Rothamsted Experimental
Station for 14 years; there, he analysed its
immense data from crop experiments since the
1840s, and developed the analysis of variance
(ANOVA). He established his reputation there
in the following years as a biostatistician.
He is known as one of the three principal
founders of population genetics. He outlined
Fisher's principle, the Fisherian runaway
and sexy son hypothesis theories of sexual
selection. His contributions to statistics
include the maximum likelihood, fiducial inference,
the derivation of various sampling distributions,
founding principles of the design of experiments,
and much more.
Fisher held strong views on race. Throughout
his life, he was a prominent supporter of
eugenics, an interest which led to his work
on statistics and genetics. Notably, he was
a dissenting voice in UNESCO's statement The
Race Question, insisting on racial differences.
== Early life and education ==
Fisher was born in East Finchley in London,
England, into a middle-class household; his
father, George, was a successful partner in
Robinson & Fisher, auctioneers and fine art
dealers. He was one of twins, with the other
twin being still-born and grew up the youngest,
with three sisters and one brother. From 1896
until 1904 they lived at Inverforth House
in London, where English Heritage installed
a blue plaque in 2002, before moving to Streatham.
His mother, Kate, died from acute peritonitis
when he was 14, and his father lost his business
18 months later.Lifelong poor eyesight caused
his rejection by the British Army for World
War I, but also developed his ability to visualize
problems in geometrical terms, not in writing
mathematical solutions, or proofs. He entered
Harrow School age 14 and won the school's
Neeld Medal in mathematics. In 1909, he won
a scholarship to study Mathematics at Gonville
and Caius College, Cambridge. In 1912, he
gained a First in Astronomy.
In 1915 he published a paper The evolution
of sexual preference on sexual selection and
mate choice.
== Career ==
During 1913–1919, Fisher worked for six
years as a statistician in the City of London
and taught physics and maths at a sequence
of public schools, at the Thames Nautical
Training College, and at Bradfield College.
There he settled with his new bride, Eileen
Guinness, with whom he had two sons and six
daughters.In 1918 he published "The Correlation
Between Relatives on the Supposition of Mendelian
Inheritance", in which he introduced the term
variance and proposed its formal analysis.
He put forward a genetics conceptual model
showing that continuous variation amongst
phenotypic traits measured by biostatisticians
could be produced by the combined action of
many discrete genes and thus be the result
of Mendelian inheritance. This was the first
step towards establishing population genetics
and quantitative genetics, which demonstrated
that natural selection could change allele
frequencies in a population, resulting in
reconciling its discontinuous nature with
gradual evolution.
Joan Box, Fisher's biographer and daughter
says that Fisher had resolved this problem
already in 1911.
=== Rothamsted Experimental Station, 1919–1933
===
In 1919, he began working at the Rothamsted
Experimental Station for 14 years, where he
analysed its immense data from crop experiments
since the 1840s, and developed the analysis
of variance (ANOVA).
In 1919, he was offered a position at the
Galton Laboratory in University College London
led by Karl Pearson, but instead accepted
a temporary job at Rothamsted in Harpenden
to investigate the possibility of analysing
the vast amount of crop data accumulated since
1842 from the "Classical Field Experiments".
He analysed the data recorded over many years
and in 1921, published Studies in Crop Variation,
and his first application of the analysis
of variance ANOVA. In 1928, Joseph Oscar Irwin
began a three-year stint at Rothamsted and
became one of the first people to master Fisher's
innovations.
Between 1912 and 1922 Fisher recommended,
analyzed (with flawed attempts at proofs)
and vastly popularized Maximum likelihood.
Fisher's 1924 article On a distribution yielding
the error functions of several well known
statistics presented Pearson's chi-squared
test and William Gosset's Student's t-distribution
in the same framework as the Gaussian distribution
and is where he developed Fisher's z-distribution
a new statistical method, commonly used decades
later as the F distribution.
He pioneered the principles of the design
of experiments and the statistics of small
samples and the analysis of real data.
In 1925 he published Statistical Methods for
Research Workers, one of the 20th century's
most influential books on statistical methods.
Fisher's method is a technique for data fusion
or "meta-analysis" (analysis of analyses).
This book also popularized the p-value, and
plays a central role in his approach. Fisher
proposes the level p=0.05, or a 1 in 20 chance
of being exceeded by chance, as a limit for
statistical significance, and applies this
to a normal distribution (as a two-tailed
test), thus yielding the rule of two standard
deviations (on a normal distribution) for
statistical significance. The 1.96, the approximate
value of the 97.5 percentile point of the
normal distribution used in probability and
statistics, also originated in this book.
"The value for which P=.05, or 1 in 20, is
1.96 or nearly 2 ; it is convenient to take
this point as a limit in judging whether a
deviation is to be considered significant
or not."
In Table 1 of the work, he gave the more precise
value 1.959964.In 1928, Fisher was the first
to use diffusion equations to attempt to calculate
the distribution of allele frequencies and
the estimation of genetic linkage by maximum
likelihood methods among populations.In 1930,
The Genetical Theory of Natural Selection
was first published by Clarendon Press and
is dedicated to Leonard Darwin. A core work
of the neo-Darwinian modern evolutionary synthesis,
it helped define population genetics, which
Fisher founded alongside Sewall Wright and
J. B. S. Haldane, and revived Darwins neglected
idea of sexual selection.
One of Fisher's favorite aphorisms was "Natural
selection is a mechanism for generating an
exceedingly high degree of improbability."Fisher's
fame grew and he began to travel and lecture
widely. In 1931, he spent six weeks at the
Statistical Laboratory at Iowa State College
where he gave three lectures per week, and
met many American statisticians, including
George W. Snedecor. He returned there again
in 1936.
=== University College London, 1933–39 ===
In 1933, Fisher became the head of the Department
of Eugenics at University College London.
In 1935, he published The Design of Experiments,
which was "also fundamental, [and promoted]
statistical technique and application... The
mathematical justification of the methods
was not stressed and proofs were often barely
sketched or omitted altogether .... [This]
led H.B. Mann to fill the gaps with a rigorous
mathematical treatment".
In this book Fisher also outlined the Lady
tasting tea, now a famous design of a statistical
randomized experiment which uses Fisher's
exact test and is the original exposition
of Fisher's notion of a null hypothesis.The
same year he also published a paper on fiducial
inference and applied it to the Behrens–Fisher
problem, the solution to which, proposed first
by Walter Behrens and a few years later by
Fisher, is the Behrens–Fisher distribution.
In 1936 he introduced the Iris flower data
set as an example of discriminant analysis.In
his 1937 paper The wave of advance of advantageous
genes he proposed Fisher's equation in the
context of population dynamics to describe
the spatial spread of an advantageous allele
and explored its travelling wave solutions.
Out of this also came the Fisher–Kolmogorov
equation.
In 1937, he visited the Indian Statistical
Institute in Calcutta, and its one part-time
employee, P. C. Mahalanobis, often returning
to encourage its development. He was the guest
of honour at its 25th anniversary in 1957,
when it had 2000 employees.In 1938, Fisher
and Frank Yates described the Fisher–Yates
shuffle in their book Statistical tables for
biological, agricultural and medical research.
Their description of the algorithm used pencil
and paper; a table of random numbers provided
the randomness.
=== University of Cambridge, 1940–1956 ===
In 1943, along with A.S. Corbet and C.B. Williams
he published a paper on relative species abundance
where he developed the logseries to fit two
different abundance data sets In the same
year he took the Balfour Chair of Genetics
where the Italian researcher Luigi Luca Cavalli-Sforza
was recruited in 1948, establishing a one-man
unit of bacterial genetics.
In 1936, Fisher used a Pearson's chi-squared
test to analyze Mendel's data and concluded
that Mendel's results with the predicted ratios
were far too perfect, suggesting that adjustments
(intentional or unconscious) had been made
to the data to make the observations fit the
hypothesis. Later authors have claimed Fisher's
analysis was flawed, proposing various statistical
and botanical explanations for Mendel's numbers.
In 1947, Fisher cofounded the journal Heredity
with Cyril Darlington and in 1949 he published
The Theory of Inbreeding.
In 1950 he published "Gene Frequencies in
a Cline Determined by Selection and Diffusion"
on the wave of advance of advantageous genes
and on clines of gene frequency, being notable
as the first application of a computer, the
EDSAC, to biology. He developed computational
algorithms for analyzing data from his balanced
experimental designs, with various editions
and translations, becoming a standard reference
work for scientists in many disciplines. In
ecological genetics he and E. B. Ford showed
how the force of natural selection was much
stronger than had been assumed, with many
ecogenetic situations (such as polymorphism)
being maintained by the force of selection.
During this time he also worked on mouse chromosome
mapping; breeding the mice in laboratories
in his own house.Fisher publicly spoke out
against the 1950 study showing that smoking
tobacco causes lung cancer, arguing that correlation
does not imply causation. To quote his biographers
Yates and Mather, "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 labours, 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."He
gave the 1953 Croonian lecture on population
genetics.In the winter of 1954–1955 Fisher
met Debabrata Basu, the Indian statistician
who wrote in 1988, "With his reference set
argument, Sir Ronald was trying to find a
via media between the two poles of Statistics
– Berkeley and Bayes. My efforts to understand
this Fisher compromise led me to the likelihood
principle".
=== Adelaide, 1957–1962 ===
In 1957, a retired Fisher emigrated to Australia,
where he spent time as a senior research fellow
at the Australian Commonwealth Scientific
and Industrial Research Organisation (CSIRO)
in Adelaide. He died there in 1962, and his
remains were interred within St Peter's Cathedral,
Adelaide.
== Personal life and beliefs ==
He married Eileen Guinness, with whom he had
two sons and six daughters.
His marriage disintegrated during World War
II, and his oldest son George, an aviator,
was killed in combat. His daughter Joan, who
wrote a biography of her father, married the
noted statistician George E. P. Box.
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." Fisher was noted for being loyal,
and was seen as a patriot, a member of the
Church of England, politically conservative,
as well as a scientific rationalist. He developed
a reputation for carelessness in his dress
and was the archetype of the absent-minded
professor. H. Allen Orr describes him in the
Boston Review as a "deeply devout Anglican
who, between founding modern statistics and
population genetics, penned articles for church
magazines". In a 1955 broadcast on Science
and Christianity, he said:
=== Parapsychology ===
Fisher was involved with the Society for Psychical
Research.
=== Eugenics ===
In 1910 Fisher joined the Eugenics Society
(UK) at University of Cambridge, whose members
included John Maynard Keynes, R. C. Punnett,
and Horace Darwin. He saw eugenics as addressing
pressing social and scientific issues that
encompassed and drove his interest in both
genetics and statistics. During World War
I Fisher started writing book reviews for
the Eugenic Review and volunteered to undertake
all such reviews for the journal, being hired
for a part-time position.
The last third of The Genetical Theory of
Natural Selection focussed on eugenics, attributing
the fall of civilizations to the fertility
of their upper classes being diminished, and
used British 1911 census data to show an inverse
relationship between fertility and social
class, partly due, he claimed, to the lower
financial costs and hence increasing social
status of families with fewer children. He
proposed the abolition of extra allowances
to large families, with the allowances proportional
to the earnings of the father. He served in
several official committees to promote eugenics.
In 1934, he resigned from the Eugenics Society
over a dispute about increasing the power
of scientists within the movement.
=== Race ===
In 1950, Fisher opposed UNESCO's The Race
Question, believing 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.
== Legacy ==
Fisher's former doctoral students include
Walter Bodmer, D. J. Finney, Mary F. Lyon
and C. R. Rao Although a prominent opponent
of Bayesian statistics, Fisher was the first
to use the term "Bayesian", in 1950. The 1930
The Genetical Theory of Natural Selection
is commonly cited in biology books, and outlines
many important concepts, such as:
Parental investment, is any parental expenditure
(time, energy etc.) that benefits one offspring
at a cost to parents' ability to invest in
other components of fitness,
Fisherian runaway, explaining how the desire
for a phenotypic trait in one sex combined
with the trait in the other sex (for example
a peacock's tail) creates a runaway development
of the trait.
Fisher's principle, which explains why the
sex ratio is mostly 1:1 in nature.
Reproductive value which implies that sexually
reproductive value measures the contribution
of an individual of a given age to the future
growth of the population.
Fisher's fundamental theorem of natural selection,
which states that "the rate of increase in
fitness of any organism at any time is equal
to its genetic variance in fitness at that
time."
Fisher's geometric model, an evolutionary
model of the effect sizes on fitness of spontaneous
mutations proposed by Fisher to explain the
distribution of effects of mutations that
could contribute to adaptive evolution.
Sexy son hypothesis, which hypothesizes that
females may choose arbitrarily attractive
male mates simply because they are attractive,
thus increasing the attractiveness of their
sons who attract more mates of their own.
This is in contrast to theories of female
mate choice based on the assumption that females
choose attractive males because the attractive
traits are markers of male fitness.
Mimicry, a similarity of one species to another
that protects one or both
Dominance, a relationship between alleles
of one gene, in which the effect on phenotype
of one allele masks the contribution of a
second allele at the same locus.
Heterozygote advantage which was later found
to play a frequent role in genetic polymorphism.
Demonstrating that the probability of a mutation
increasing the fitness of an organism decreases
proportionately with the magnitude of the
mutation and that larger populations carry
more variation so that they have a greater
chance of survival.Fisher is also known for:
Linear discriminant analysis is a generalization
of Fisher's linear discriminant
Fisher information, see also scoring algorithm
also known as Fisher's scoring, and Minimum
Fisher information, a variational principle
which, when applied with the proper constraints
needed to reproduce empirically known expectation
values, determines the best probability distribution
that characterizes the system.
F-distribution, arises frequently as the null
distribution of a test statistic, most notably
in the analysis of variance
Fisher–Tippett–Gnedenko theorem Fisher's
contribution to this was made in 1927
Fisher–Tippett distribution
Von Mises–Fisher distribution
Inverse probability, a term Fisher used in
1922, referring to "the fundamental paradox
of inverse probability" as the source of the
confusion between statistical terms which
refer to the true value to be estimated, with
the actual value arrived at by estimation,
which is subject to error.
Fisher's permutation test
Fisher's inequality
Sufficient statistic, when a statistic is
sufficient with respect to a statistical model
and its associated unknown parameter if "no
other statistic that can be calculated from
the same sample provides any additional information
as to the value of the parameter".
Fisher's noncentral hypergeometric distribution,
a generalization of the hypergeometric distribution,
where sampling probabilities are modified
by weight factors.
Student's t-distribution, widely used in statistics.
== Recognition ==
Fisher was elected to the Royal Society in
1929. He was made a Knight Bachelor by Queen
Elizabeth II in 1952 and awarded the Linnean
Society of London Darwin–Wallace Medal in
1958.
He won Copley Medal and the Royal Medal. He
was an Invited Speaker of the ICM in 1924
in Toronto and in 1928 in Bologna.In 1950,
Maurice Wilkes and David Wheeler used the
Electronic Delay Storage Automatic Calculator
to solve a differential equation relating
to gene frequencies in a paper by Ronald Fisher.
This represents the first use of a computer
for a problem in the field of biology. The
Kent distribution (also known as the Fisher–Bingham
distribution) was named after him and Christopher
Bingham in 1982 while Fisher kernel was named
after Fisher in 1998.The R. A. Fisher Lectureship
is a North American annual lecture prize,
established in 1963. On 28 April 1998 a minor
planet, 21451 Fisher, was named after him.
Anders Hald called Fisher "a genius who almost
single-handedly created the foundations for
modern statistical science", while Richard
Dawkins named him "the greatest biologist
since Darwin": Not only was he the most original
and constructive of the architects of the
neo-Darwinian synthesis, Fisher also was the
father of modern statistics and experimental
design. He therefore could be said to have
provided researchers in biology and medicine
with their most important research tools,
as well as with the modern version of biology's
central theorem.
Geoffrey Miller said of him:To biologists,
he was an architect of the "modern synthesis"
that used mathematical models to integrate
Mendelian genetics with Darwin's selection
theories. To psychologists, Fisher was the
inventor of various statistical tests that
are still supposed to be used whenever possible
in psychology journals. To farmers, Fisher
was the founder of experimental agricultural
research, saving millions from starvation
through rational crop breeding programs.
== Bibliography
