## Karl Pearson

Karl Pearson was a major player in the early development of statistics as a serious scientific discipline in its own right. He founded the Department of Applied Statistics (now the Department of Statistical Science) at University College London in 1911; it was the first university statistics department in the world. The present departments ofStatistical Science and Computer Science, as well as the Genetics and Biometry group in Biology and the physical side of Anthropology are all part of his legacy to UCL.

This page contains a brief biography, as well as some indications of his contributions to the subject.

### Biographical details

Karl Pearson was born in London on the 27th March 1857. He was educated privately at University College School, after which he went to King's College Cambridge to study mathematics. He then spent part of 1879 and 1880 studying medieval and 16th century German literature at the universities of Berlin and Heidelberg - in fact, he became sufficently knowledgeable in this field that he was offered a post in the German department at Cambridge University.

His next career move was to Lincoln's Inn, where he read law until 1881 (although he never practised). After this, he returned to mathematics, deputising for the mathematics professor at King's College London in 1881 and for the professor at University College London in 1883. In 1884, he was appointed to the Goldshmid Chair of Applied Mathematics and Mechanics at University College London. 1891 saw him also appointed to the professorship of Geometry at Gresham College; here he met W.F.R. Weldon, a zoologist who had some interesting problems requiring quantitative solutions. The collaboration, in biometry and evolutionary theory, was a fruitful one and lasted until Weldon died in 1906. Weldon introduced Pearson to Francis Galton, who was interested in aspects of evolution such as heredity and eugenics, and this was another very rewarding partnership, more for the developments in statistics it led to than for the eugenics, some of which is rather problematic for a modern reader with knowledge of subsequent developments.

Galton died in 1911 and left the residue of his estate to the University of London for a Chair in Eugenics. Pearson was the first holder of this chair, in accordance with Galton's wishes. He formed the Department of Applied Statistics, into which he incorporated the Biometric and Galton laboratories. He remained with the department until his retirement in 1933, and continued to work until his death in 1936.

Pearson married Maria Sharpe in 1890, and between them they had 2 daughters and a son. The son, Egon Sharpe Pearson, succeeded him as head of the Applied Statistics Department at University College.

Aside from his professional life, Pearson was active as a prominent free thinker and socialist. He gave lectures on such issues as "the woman's question" (this was the era of the suffragette movement in the UK) and upon Karl Marx. His commitment to socialism and its ideals led him to refuse an OBE (Order of the British Empire) when it was offered in 1920, and also a Knighthood in 1935.

### Awards from professional bodies

Pearson achieved widespread recognition across a range of disciplines and his membership of, and awards from, various professional bodies reflects this:

- 1896: elected Fellow of the Royal Society
- 1898: awarded the Darwin Medal
- 1911: awarded the honorary degree of LLD from St Andrews University
- 1911: awarded a DSc from University of London
- 1920: offered (and refused) the OBE
- 1932: awarded the Rudolf Virchow medal by the Berliner Anthropologische Gesellschaft
- 1935: offered (and refused) a knighthood

He was also elected an Honorary Fellow of King's College Cambridge, the Royal Society of Edinburgh, University College London and the Royal Society of Medicine, and a Member of the Actuaries' Club.

### Contributions to statistics

Pearson's work was all-embracing in the wide application and development of mathematical statistics, and encompassed the fields of biology, epidemiology, anthropometry, medicine and social history. In 1901, with Weldon and Galton, he founded the journal Biometrika whose object was the development of statistcal theory. He edited this journal till his death. He also founded the journal Annals of Eugenics (now Annals of Human Genetics) in 1925.

Pearson's thinking underpins many of the `classical' statistical methods which are in common use today. Some of his main contributions are:

##### Linear regression and correlation

Pearson was instrumental in the development of this theory. One of his classic data sets involves the regression of sons' height upon that of their fathers'. Pearson built a 3-dimensional model of this data set (which remains in the care of the Statistical Science Department) to illustrate the ideas. The Pearson correlation coefficient is named after him.

##### Classification of distributions

Pearson's work on classifying probability distributions forms the basis for a lot of modern statistical theory; in particular, the exponential family of distributions underly the theory of Generalized Linear Models.

### Other useful sites

The interested reader may find the following links of use:

- The MacTutor History of Mathematics archive at St. Andrews University includes biographies of mathematicians and statisticians (including Pearson), as well as general information on the history of mathematics.
- John Aldrich's Karl Pearson: a Reader's Guide contains many useful links to further sources of information.

### Further reading

Most of the biographical information above is taken from A list of the papers and correspondence of Karl Pearson (1857-1936) held in the Manuscripts Room, University College London Library, compiled by M.Merrington, B.Blundell, S.Burrough, J.Golden and J.Hogarth and published by the Publications Office, University College London, 1983.

Further references which may be of use are:

- Eisenhart, Churchill (1974): Dictionary of Scientific Biography, pp.447-73. New York, 1974.
- Filon, L.N.G. and Yule, G.U. (1936): Obituary Notices of the Royal Society of London, Vol. ii, No.5, pp.73-110.
- Pearson, E.S. (1938): Karl Pearson: an appreciation of some aspects of his life and work. Cambridge University Press.

John Aldrich's Reader's Guide provides a much more extensive bibliography.