In an interview given some years ago, Dr. Calyampudi Radhakrishna Rao had quoted, tongue-in-cheek, one of his mentors, famous statistician and geneticist Ronald A. Fisher, “A ballet dancer gets her ovation on the spot, while she is still warm from her efforts. A wit gets his laugh across the table, but a scientist must expect to wait about five years for his laugh. Recognition in science, to the man who has something to give, is, I guess, more just and more certain than in most occupations but it does take time. And when it comes, it will probably come from abroad.”
Dr. Rao went on to say, “The first award I received came from abroad. It was the Fellowship of The Royal Society [FRS].” That was a long time ago in 1967. He has been honoured with Padma Vibhushan in 2001 and was awarded the Indian Science Prize in 2010. On June 12, 2002, he was presented the National Medal of Science by U.S. President George W. Bush “for his pioneering contributions to the foundation of statistical theory and multivariate statistical methodology, and their applications, enriching the physical, biological, mathematical, economic and engineering sciences”.
On September 10, we celebrate the birth centenary of this living legend. This is an occasion to celebrate not only for the honour bestowed on the most-respected statistician in the world today, but also because statistics has become an indispensable applied tool in all walks of life through Dr. Rao’s contributions and efforts.
Dr. Rao has defined statistics as “the science of learning from data.” We are now passing through an age of data revolution. The demand for statisticians in global employment is one of the highest and the demand is predicted to increase in the coming years. “I was fortunate to have made some fundamental contributions to the field of statistics and to see the impact of my work in furthering research. In my lifetime, I have seen statistics grow into a strong independent field of study … its importance has spread across numerous areas such as business, economics, health and medicine, banking, management, physical, natural, and social sciences.”
Dr. Rao is the eighth in a family of 10 children. His father, C.D. Naidu, who worked in the police department, attached great importance to the scholastic achievement of his children. His mother, A Laxmikantamma, was a stern disciplinarian. Dr. Rao dedicated his book Statistics and Truth to her “for instilling in me the quest for knowledge” and “who, in my younger days, woke me up every-day at four in the morning and lit the oil lamp for me to study in the quiet hours of the morning when the mind is fresh.”
Dr. Rao developed an interest in mathematics from an early age. As a six-year-old boy, he knew by heart the multiplication tables up to 20 by 20. He won the Chandrasekara Iyer Scholarship, named after C.V. Raman’s father, in physics in Intermediate. However, he decided to pursue a career in mathematics, joined Andhra University and obtained the equivalent of a Master’s degree even before he was 20. Pressure from his family forced him to prepare for the entrance test for the Indian Civil Service (ICS).
While he had a to wait for about 18 months for the test, he decided to take a job and came to Calcutta to face an interview. A chance meeting with a young man, Mr. Subramanian, in a south Indian hotel on this trip was to change his life. Mr. Subramanian was undergoing training in statistics at the Indian Statistical Institute (ISI). He took him to ISI, which was then located in the physics department of the Presidency College. Dr. Rao joined ISI in 1941 in a training programme. His father had just passed away and there was financial stress in the family. However, his elder brother and mother encouraged him to pursue the training at the ISI.
“I did not learn much from the courses” during the training programme, Dr. Rao said. However, he came into contact with three well-known statisticians, Raj Chandra Bose, Samarendra Nath Roy and Keshvan Raghvan Nair, who were all working in the ISI, but did not participate in teaching. Within three months of joining the ISI, Dr. Rao wrote his first scientific paper with Nair. In July 1941, while he was still a student in the one-year training programme in the ISI, the Master’s programme in statistics was started in Calcutta University, with Prasanta Chandra Mahalanobis as head of the statistics department. This was the first degree course in statistics in India. Dr. Rao enrolled himself as a student and graduated in 1943 with a first rank, obtaining 87.5 per cent marks, still a record at Calcutta University. While a Master’s student, he published several papers with Raj Chandra Bose. His M.A. dissertation contained original contributions to several areas of statistics.
After he obtained M.A., Prasanta Chandra Mahalanobis offered Dr. Rao a job in the ISI as a technical apprentice in November 1943. In 1946, Mahalanobis sent Dr. Rao to Cambridge to carry out statistical analyses of some data on skeletal material collected by J.C. Trevor. “The period from January 1944 to July 1946, before going to Cambridge, was, perhaps, the most eventful of my research career,” Dr. Rao has recalled. While he was teaching a course on statistics at the Calcutta University in 1944, he derived a seminal result with which his name is associated – the Cramer-Rao bound.
In 1945, he proved a result that is now known as the Rao-Blackwell theorem. Often, we need to obtain knowledge of an unknown feature of a population; for example, the average monthly income of Bengali. It is not usually not possible to study every member of the population; it is not possible to collect income data from every Bengali living anywhere in the world. Data can be collected only from a small number of Bengalis suitably selected. From these data, one can then obtain an approximate, not the exact, knowledge – an estimate. There are several ways of obtaining estimates from data, but the method proposed by Dr. Rao, and two years later by David Blackwell, results in highly reliable estimates.
In Cambridge, Dr. Rao registered for a PhD under Ronald A. Fisher, a founder of modern statistical science. Fisher told Dr. Rao to find his own problem to solve and write a PhD thesis, and asked him to seek his advice only when he “encountered difficulties”. Fisher worked in the genetics, not in the statistics, department. He asked Dr. Rao to spend some time in the genetics laboratory. Fisher was trying to find which genes were on which chromosomes in the mouse. Dr. Rao did it and proposed a novel method to find how physically close two genes are. The method bears his name – Rao’s Score Test – and is now used in all branches of science, both natural and social.
After submitting his PhD thesis, Dr. Rao returned to India from England in 1948 and became a professor at ISI at the age of 28. In 1964, he assumed directorship of the ISI. After his retirement from ISI, he moved to the U.S. In 1982, he established the Center of Multivariate Analysis at the University of Pittsburgh. He joined the Pennsylvania State University in 1988.
Dr. Rao’s contributions to mathematics and statistical theory and applications have become part of graduate and postgraduate courses in statistics, econometrics, electrical engineering, and many other disciplines at universities throughout the world. His scholarship has heavily influenced the theory and application of statistics in such diverse fields as anthropology, geology, biology, psychology, social sciences, and national planning. His work in multivariate analysis, for example, is used to improve economic planning, weather prediction, medical diagnosis, tracking the movements of spy planes, and monitoring the course of spacecraft.
Dr. Rao has authored or co-authored 14 books and more than 300 research papers. His book Linear Statistical Inference and its Applications , published in 1965, has been translated into six languages and has remained as one of the most cited books in science.
When I joined the ISI as a student of the B.Stat. course in 1970, his presence could be felt in every corner of the institute. As students, we were in awe. Such a famous person, but so unassuming, so soft-spoken and so polite. He had an uncanny and a subtle sense of humour. In his lectures, even on theoretical statistics, he always began by motivating the topic with a practical example. He has always emphasized that statistical research, even on statistical theory, should largely arise form real-life problems. He has spent his entire career promoting statistics and their usefulness in society. “If there is a problem to be solved, seek statistical advice instead of appointing a committee of experts. Statistics can throw more light than the collective wisdom of the articulate few,” he has said.
Dr. Rao has categorized creativity into two different kinds. “At its highest level, it is the birth of a new idea or a theory which is qualitatively different from and not conforming to or deducible from any existing paradigm, and which explains a wider set of natural phenomena than any existing theory. There is creativity of another kind at a different level, of a discovery made within the framework of an existing paradigm but of immense significance in a particular discipline.”
Dr. Rao has excelled in creativity of both kinds, which is why he is the most respected statistician in the world today.
(Partha P. Majumder is National Science Chair and President, Indian Academy of Sciences)
Published - September 09, 2020 02:52 pm IST
