## Oscar Kempthorne (1919–2000)

*by Klaus Hinkelmann*

Born into a farm family on January 31, 1919, in St. Tudy, Cornwall, Oscar Kempthorne made up his mind very early that he wanted to get away from the backbreaking work on the farm. And he realized that this could only be accomplished through more education, or as he put it: “There was only one way to do it—brain power” (Des Moines Register, 11/25/90). As a consequence, he studied very hard on his own, but, fortunately, also some of the teachers in his rural school recognized his talents and supported him in his quest. He especially loved mathematics, and in secondary school his knowledge surpassed that of his teachers. So, he taught himself mathematics and, thus, prepared himself for a university education.
In 1937 his hard work paid off as he won scholarships to Cambridge University. In his first two years there he took a great number of mathematics courses, but “got turned off from pure mathematics because it did not seem to be going anywhere” (Folks, 1995). Also a brief foray into mathematical physics did not catch his imagination. Then, finally, he had a first course in statistics from John Wishart, which seemed to interest him. Inspired by some of R. A. Fisher’s writings, the idea that mathematics should be useful and could be useful in agricultural research impressed him tremendously. He subsequently took a two-term statistics course from J. O. Irwin, which would complete his formal training in statistics. In 1940 he received a B.A. degree with Honours from Cambridge University and the M.S. degree in 1943.

After working briefly for the British Ministry of Supply, he joined Rothamsted Experiment Station in 1941. Here he met R. A. Fisher and Frank Yates. These two men had contributed greatly to the prominence of Rothamsted through their groundbreaking work in experimental design, a field to which Kempthorne later also would make important contributions. During his time at Rothamsted, Kempthorne had actually very little contact with Fisher. As Kempthorne put it himself “He was there, but I was a boy; I didn’t know enough to ask him a question or to speak to him about anything” (Folks, 1995). Yet, he regarded Fisher as having the greatest influence in his professional life and he thought that Fisher was, by far, the greatest statistician that humanity has produced (Folks, 1995). It is, therefore, not surprising that Kempthorne became attracted to the areas of statistics that had been shaped in big measure by Fisher: experimental design, genetic statistics, and statistical inference.

Kempthorne left Rothamsted when he was asked to participate, as a member of a technical statistical group, to observe and evaluate the Greek elections in 1946. This work brought him in contact with Ray Jessen, a survey sampling expert from Iowa State College and the leader of the group. This was at the time that a Statistics Department was being established at Iowa State College. Following the Greek mission, he was offered a position as Associate Professor at Iowa State in 1947. This was the beginning of an association that would last 42 years until his retirement in 1989. He was promoted to Full Professor in 1951 and was named Distinguished Professor in Sciences and Humanities in 1964.

The Statistical Laboratory at Iowa State had achieved great prominence through the work of George W. Snedecor and the staff he had assembled between 1933 and 1947 (for a detailed account see David, 1984). The establishment of the Statistics Department would add greatly to the statistical activities at Iowa State, and Kempthorne would come to play an important role in expanding and promoting these activities through his teaching, research, writing, and consulting.

His first great success came with the publication of his book Design and Analysis of Experiments published by Wiley in 1952. It was the first comprehensive treatment of experimental design at a “theoretical” level intended for graduate studies and research in this field. It built upon the foundations laid by Fisher and Yates, but Kempthorne was able to carry the development much further and thus paint a much broader and unified picture of this field. Fisher’s notion of randomization was cast in a more mathematical-probabilistic framework, which led to important consequences with regard to the development of linear models and modes of inference resulting from the analysis of variance. Based on randomization theory, he pointed out the asymmetry of blocking and treatment factors in the linear model in that one can test hypotheses about treatment factors, but not about blocking factors (these ideas were exposited more fully in the 1994 book Design and Analysis of Experiments. Vol. 1. Introduction to Experimental Design by Hinkelmann and Kempthorne). A comment by Folks (1984) puts this idea in the right perspective: “As a beginning doctoral student at Iowa State University, I made the comment to him [Kempthorne] that a two-factor experiment and a randomized block design resulted in the same model. I learned very quickly that my education was not complete—that there was a fundamental difference between these two situations resulting from the randomization”. In addition to his pioneering work on randomization, Kempthorne provided a unified treatment of the general sn factorial experiment with s being a prime or prime power. With a new parametrization for the observations from such an experiment, he laid a more mathematical framework for and brought new insights to the important concepts of systems of confounding and fractional factorials.

Amazingly, only five years later Kempthorne published, again with Wiley, another groundbreaking book entitled An Introduction to Genetic Statistics. In the preface he writes: “My basic debt with regard to the whole book is to Sir Ronald A. Fisher. There is hardly a page, even less a chapter, which does not contain the results of Fisher and extensions of Fisher’s results” (Kempthorne, 1957). It also makes use of important contributions due to Sewall Wright, J. B. S. Haldane, and G. Malécot, but it is the extensions and applications of the results of these and other writers that make this book such an important addition to the genetics and statistics literature. Many of these extensions and new results represent Kempthorne’s own research, which was heavily stimulated by the environment in which he found himself at Iowa State and the interaction he had with plant and animal breeders, among them Jay L. Lush, one of the premier animal breeders at the time. Although, as he points out: “The present book is not a book on breeding theory and procedures”, it nevertheless provides the theoretical framework and underpinnings for such procedures with its detailed development and discussion of fundamental concepts in the context of both population genetics and quantitative inheritance. Among these concepts are selection theory, the theory of inbreeding, the notion of covariances between relatives for various types of genetic populations and mating types within populations, as well as the role of analysis of variance as it applies to quantitative inheritance and the estimation of genetic parameters, such as genetic variance components and combining abilities. It is no wonder that, with such a broad exposition, this book became a standard text and provided the tools for many developments in quantitative genetics research today.

A third area to which Kempthorne contributed heavily, in particular in the latter part of his professional life, is that of the foundations and philosophy of statistical science. It is interesting to note that as a student he “did not really understand what philosophy was about or that there were such people as philosophers” to which he adds ” and I am not much better off now about that” (Folks, 1995). That, of course, is a typical Kempthorne understatement. He became an avid reader of the works of many of the important philosophers, like Kant, Schopenhauer, Nietzsche (as somebody who abhors philosophy I remember with some embarrassment my occasional failures to properly explain to him the meaning of some of the German words used by these philosophers) or philosophers of science, like Carnap, Peirce, Popper. He thought and wrote a great deal about how their ideas applied to the field of statistics and its foundations. Much of his own philosophy can be found in the book Probability, Statistics, and Data Analysis (Kempthorne and Folks, 1971), published by Iowa State University Press. He drew a sharp distinction between theoretical and applied statistics and felt that data analysis was at the heart of statistics. He instilled this view in his students and in the overall direction of the Statistics Department at Iowa State when he says: “What accounts for the success of the Stat Lab [at Iowa State]? I believe that it is because it was not driven by the mathematics, but by actual problems in biology, genetics, demography, economics, philosophy and so on. To be sure, the real problems give rise to abstract problems in statistical inference, which have a fascination of their own. However, for statistics to remain viable, statistical problems should have their genesis in real, data-related problems” (Folks, 1995).

For all his broad and varied contributions Oscar Kempthorne was recognized by his peers and by the scientific community with numerous awards and honors, such as Fellow of the American Statistical Association, Fellow and President of the Institute of Mathematical Statistics, Fellow of the American Association for the Advancement of Science, Elected Member of the International Statistical Institute, Sc.D. degree from Cambridge University, Honorary Fellow of the Royal Statistical Society, and an Honorary Doctorate from the University of Ioannina (Greece).

Kempthorne was a consummate teacher. He literally bombarded his students with handouts to supplement his lectures and expected them to work through every word and formula. He loved and was loved by (most of) his students and feared by them at the same time, because he demanded a lot. In a “Letter to Friends” on the occasion of his 65th birthday he wrote: “Give me arrogant but competent young people”. During his 42 years at Iowa State University he directed the work of 43 PhD students, and he always took great pride in their later accomplishments.

In the same “Letter to Friends” he wrote: “I view myself as a person who is kindly, but sometimes harsh. My wife [Valda Marie, who was his strongest supporter] tells me so, and correctly. She says: ‘Go off and pursue your holy grail, and forget about the humans you should pay attention to.’ I find myself with friends, all over the world. How did this happen to a Cornish farm boy? Was it genes, environment or altruism? I do not know.” Surely, those of us who had the privilege of knowing Oscar Kempthorne, have an answer, and, it is hoped those who only read about him and read his work, will share in our admiration for him.

ReferencesDavid, H. A. (1984). The Iowa State Statistical Laboratory: Antecedents and early years.

Statistics—An Appraisal(H. A. David and H. T. David, eds.) 3–18. Iowa State Univ. Press, Ames.Folks, J. L. (1984). Use of Randomization in Experimental Research.

Experimental Design, Statistical Models, and Genetic Statistics—Essays in Honor of Oscar Kempthorne(K. Hinkelmann, ed.) 17–32. Dekker, New York.Folks, J. L. (1995). A Conversation with Oscar Kempthorne.

Statist. Science 10 321–336

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