Oscar Kempthorne
Encyclopedia
Oscar Kempthorne was a statistician
and geneticist
known for his research on randomization-analysis and the design of experiments
, which had wide influence on research in agriculture, genetics, and other areas of science. Born in St Tudy
, Cornwall
and educated in England, Kempthorne moved to the United States, where he was for many decades a professor at Iowa State University.
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
. Kempthorne was skeptical of "statistical model
s" (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
of Donald Rubin
; in turn, Rubin's randomization-based analysis and his work with Rosenbaum on propensity score
s influenced Kempthorne's analysis of covariance.
-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 and John Nelder
; neo-Fisherian statistics emphasizes likelihood function
s of parameters.
Second, Kempthorne was skeptical of Bayesian statistics
, which use not only likelihoods but also probability distributions on parameters.
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 Hinklemann (2004), Kempthorne wrote,
Statistician
A statistician is someone who works with theoretical or applied statistics. The profession exists in both the private and public sectors. The core of that work is to measure, interpret, and describe the world and human activity patterns within it...
and geneticist
Geneticist
A geneticist is a biologist who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a researcher or lecturer. Some geneticists perform experiments and analyze data to interpret the inheritance of skills. A geneticist is also a Consultant or...
known for his research on randomization-analysis and the design of experiments
Design of experiments
In general usage, design of experiments or experimental design is the design of any information-gathering exercises where variation is present, whether under the full control of the experimenter or not. However, in statistics, these terms are usually used for controlled experiments...
, which had wide influence on research in agriculture, genetics, and other areas of science. Born in St Tudy
St Tudy
St Tudy is a civil parish and village in north Cornwall, United Kingdom. The village is situated in the River Camel valley approximately five miles northeast of Wadebridge.-Parish church:...
, Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
and educated in England, Kempthorne moved to the United States, where he was for many decades a professor 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 A. Fisher, particularly Fisher's youthful writings on randomized experiments.Kempthorne is the founder of the "Iowa school" of experimental design and analysis of variance
Analysis of variance
In statistics, analysis of variance is a collection of statistical models, and their associated procedures, in which the observed variance in a particular variable is partitioned into components attributable to different sources of variation...
. Kempthorne and many of his former doctoral students have often emphasized the use of the randomization distribution under the null hypothesis
Null hypothesis
The practice of science involves formulating and testing hypotheses, assertions that are capable of being proven false using a test of observed data. The null hypothesis typically corresponds to a general or default position...
. Kempthorne was skeptical of "statistical model
Statistical model
A statistical model is a formalization of relationships between variables in the form of mathematical equations. A statistical model describes how one or more random variables are related to one or more random variables. The model is statistical as the variables are not deterministically but...
s" (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
Rubin Causal Model
The Rubin Causal Model is an approach to the statistical analysis of cause and effect based on the framework of potential outcomes. RCM is named after Donald Rubin, Professor of Statistics at Harvard University...
of Donald Rubin
Donald Rubin
Donald Bruce Rubin is the John L. Loeb Professor of Statistics at Harvard University. He was hired by Harvard in 1984, and served as chair of the department from 1985-1994....
; in turn, Rubin's randomization-based analysis and his work with Rosenbaum on propensity score
Propensity score
In the design of experiments, a propensity score is the probability of a unit being assigned to a particular condition in a study given a set of known covariates...
s influenced Kempthorne's analysis of covariance.
Model-based analysis
Oscar Kempthorne was skeptical towards (and often critical of) modelStatistical model
A statistical model is a formalization of relationships between variables in the form of mathematical equations. A statistical model describes how one or more random variables are related to one or more random variables. The model is statistical as the variables are not deterministically but...
-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 and John Nelder
John Nelder
John Ashworth Nelder FRS was a British statistician known for his contributions to experimental design, analysis of variance, computational statistics, and statistical theory.-Contributions:...
; neo-Fisherian statistics emphasizes likelihood function
Likelihood function
In statistics, a likelihood function is a function of the parameters of a statistical model, defined as follows: the likelihood of a set of parameter values given some observed outcomes is equal to the probability of those observed outcomes given those parameter values...
s of parameters.
Second, Kempthorne was skeptical of Bayesian statistics
Bayesian statistics
Bayesian statistics is that subset of the entire field of statistics in which the evidence about the true state of the world is expressed in terms of degrees of belief or, more specifically, Bayesian probabilities...
, which use not only likelihoods but also probability distributions on parameters.
Nonetheless, while subjective probability
Bayesian probability
Bayesian probability is one of the different interpretations of the concept of probability and belongs to the category of evidential probabilities. The Bayesian interpretation of probability can be seen as an extension of logic that enables reasoning with propositions, whose truth or falsity is...
and Bayesian inference
Bayesian inference
In statistics, Bayesian inference is a method of statistical inference. It is often used in science and engineering to determine model parameters, make predictions about unknown variables, and to perform model selection...
were viewed skeptically by Kempthorne, Bayesian experimental design
Bayesian experimental design
Bayesian experimental design provides a general probability-theoretical framework from which other theories on experimental design can be derived. It is based on Bayesian inference to interpret the observations/data acquired during the experiment...
was defended. In the preface to his second volume with Hinklemann (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)
Writings about Oscar Kempthorne
See also
- Analysis of varianceAnalysis of varianceIn statistics, analysis of variance is a collection of statistical models, and their associated procedures, in which the observed variance in a particular variable is partitioned into components attributable to different sources of variation...
- Bayesian experimental designBayesian experimental designBayesian experimental design provides a general probability-theoretical framework from which other theories on experimental design can be derived. It is based on Bayesian inference to interpret the observations/data acquired during the experiment...
- BiostatisticsBiostatisticsBiostatistics is the application of statistics to a wide range of topics in biology...
("Biometry" or "Biometrics") - Design of experimentsDesign of experimentsIn general usage, design of experiments or experimental design is the design of any information-gathering exercises where variation is present, whether under the full control of the experimenter or not. However, in statistics, these terms are usually used for controlled experiments...
- GeneticsGeneticsGenetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
- Optimal designOptimal designOptimal designs are a class of experimental designs that are optimal with respect to some statistical criterion.In the design of experiments for estimating statistical models, optimal designs allow parameters to be estimated without bias and with minimum-variance...
- Philosophy of sciencePhilosophy of scienceThe philosophy of science is concerned with the assumptions, foundations, methods and implications of science. It is also concerned with the use and merit of science and sometimes overlaps metaphysics and epistemology by exploring whether scientific results are actually a study of truth...
- Philosophy of statisticsPhilosophy of statisticsThe philosophy of statistics involves the meaning, justification, utility, use and abuse of statistics and its methodology, and ethical and epistemological issues involved in the consideration of choice and interpretation of data and methods of Statistics....
- Random assignmentRandom assignmentRandom assignment or random placement is an experimental technique for assigning subjects to different treatments . The thinking behind random assignment is that by randomizing treatment assignment, then the group attributes for the different treatments will be roughly equivalent and therefore any...
- RandomizationRandomizationRandomization is the process of making something random; this means:* Generating a random permutation of a sequence .* Selecting a random sample of a population ....
- Randomized block designRandomized block designIn the statistical theory of the design of experiments, blocking is the arranging of experimental units in groups that are similar to one another. Typically, a blocking factor is a source of variability that is not of primary interest to the experimenter...
- Randomized clinical trial