Oscar Kempthorne (January 31, 1919 – November 15, 2000) was a British statistician and

geneticist A geneticist is a biologist or physician who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a scientist or a lecturer. Geneticists may perform general research on genetic processes ...

known for his research on randomization-analysis and the

design of experiments The design of experiments (DOE, DOX, or experimental design) is the design of any task that aims to describe and explain the variation of information under conditions that are hypothesized to reflect the variation. The term is generally associ ...

, which had wide influence on research in agriculture, genetics, and other areas of science. Born in St Tudy,

Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...

and educated in England, Kempthorne moved to the United States, where he was for many decades a professor of statistics at Iowa State University.

Randomization analysis

Kempthorne developed a randomization-based approach to the statistical analysis of randomized experiments, which was expounded in pioneering textbooks and articles. Kempthorne's insistence on randomization followed the early writings of

Ronald Fisher Sir Ronald Aylmer Fisher (17 February 1890 – 29 July 1962) was a British polymath who was active as a mathematician, statistician, biologist, geneticist, and academic. For his work in statistics, he has been described as "a genius who ...

, especially on randomized experiments. Kempthorne is the founder of the "Iowa school" of experimental design and analysis of variance. Kempthorne and many of his former doctoral students have often emphasized the use of the randomization distribution under the

null hypothesis In scientific research, the null hypothesis (often denoted ''H''0) is the claim that no difference or relationship exists between two sets of data or variables being analyzed. The null hypothesis is that any experimentally observed difference is d ...

. Kempthorne was skeptical of " statistical models" (of populations), when such models are proposed by statisticians rather than created using objective randomization procedures. Kempthorne's randomization-analysis has influenced the

causal model In the philosophy of science, a causal model (or structural causal model) is a conceptual model that describes the causal mechanisms of a system. Causal models can improve study designs by providing clear rules for deciding which independent va ...

of Donald Rubin; in turn, Rubin's randomization-based analysis and his work with Rosenbaum on

propensity score matching In the statistical analysis of observational data, propensity score matching (PSM) is a statistical matching technique that attempts to estimate the effect of a treatment, policy, or other intervention by accounting for the covariates that predic ...

influenced Kempthorne's analysis of covariance.

Model-based analysis

Oscar Kempthorne was skeptical towards (and often critical of)

model A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure. Models c ...

-based inference, particularly two influential alternatives: Kempthorne was skeptical of, first, neo-Fisherian statistics, which is inspired by the later writings of Ronald A. Fisher and by the contemporary writings of

David R. Cox Sir David Roxbee Cox (15 July 1924 – 18 January 2022) was a British statistician and educator. His wide-ranging contributions to the field of statistics included introducing logistic regression, the proportional hazards model and the Cox pro ...

and John Nelder; neo-Fisherian statistics emphasizes

likelihood function The likelihood function (often simply called the likelihood) represents the probability of random variable realizations conditional on particular values of the statistical parameters. Thus, when evaluated on a given sample, the likelihood funct ...

s of parameters. Second, Kempthorne was skeptical of

Bayesian statistics Bayesian statistics is a theory in the field of statistics based on the Bayesian interpretation of probability where probability expresses a ''degree of belief'' in an event. The degree of belief may be based on prior knowledge about the event, ...

, which use not only likelihoods but also probability distributions on parameters.However, Kempthorne recognized that the planning of experiments used scientific knowledge and beliefs, and therefore Kempthorne was interested in optimal designs, especially Bayesian experimental design:

The optimal design is dependent upon the unknown theta, and there is no choice but to invoke prior information about theta in choosing the design. I would like to say there has never been the slightest argument about this. In the design of experiments, one has to use some informal prior knowledge. (Folks, 334)

Kempthorne's skepticism towards Bayesian inference focused on the prior's use in analyzing data from randomized experiments; for analyzing data from randomized experiments, Kempthorne advocated using the objective randomization-distribution, which was induced by the randomization specified in the experimental protoocol and implemented in the actual experimental plan. Nonetheless, while subjective probability and Bayesian inference were viewed skeptically by Kempthorne, Bayesian experimental design was defended. In the preface to his second volume with Hinkelmann (2004), Kempthorne wrote,

We strongly believe that design of experiment is a Bayesian experimentation process, ... one in which the experimenter approaches the experiment with some beliefs, to which he accommodates the design. (xxii)

Bibliography

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Writings about Oscar Kempthorne

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Notes

External links