# C. Radhakrishna Rao, a living legend

Thanks to the contributions and efforts of Dr Rao, statistics have become an indispensable applied tool in all fields

In an interview given a few years ago, Dr Calyampudi Radhakrishna Rao had ironically quoted one of his mentors, the famous statistician and geneticist Ronald A. Fisher, “A ballet dancer receives a standing ovation, while ‘she is always hot from her efforts. A spirit makes laughter across the table, but a scientist should expect to wait around five years to laugh. Recognition in science, to the man who has something to give, is, I suppose, fairer and more certain than in most professions, but it takes time. And when it does, it will probably come from abroad. ”

Dr Rao went on to say, “The first award I received came from overseas. It was the Royal Society scholarship [FRS]. That was a long time ago in 1967. He was honored with Padma Vibhushan in 2001 and received the Indian Science Prize in 2010. On June 12, 2002, he was awarded the National Science Medal by the US 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 centenary of the birth of this living legend. This is an opportunity to celebrate not only for the honor bestowed on the most respected statistician in the world today, but also because statistics have become an indispensable applied tool in all fields thanks to the contributions and efforts of Dr. Rao.

Dr Rao defined statistics as “the science of learning from data”. We are now living through an era of data revolution. The demand for statisticians in global employment is one of the highest and the demand is expected to increase in the coming years. “I have been fortunate to have made fundamental contributions to the field of statistics and to see the impact of my work on the advancement of research. Over the course of my life I have seen statistics become a strong independent field of study … its importance has spread to many 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, CD Naidu, who worked in the police department, attached great importance to his children’s academic success. Her mother, A Laxmikantamma, was a severe disciplinarian. Dr Rao dedicated his book *Statistics and truth* to her “for instilling in me the quest for knowledge” and “who, in my youth, woke me up every day at four in the morning and lit the oil lamp so that I could study in the quiet hours of the morning when the l he mind is fresh.

Dr. Rao developed an interest in mathematics from an early age. By the age of six, he knew multiplication tables up to 20 by 20 by heart. He won the Chandrasekara Iyer Fellowship, named after CV Raman’s father, in physics through intermediate. However, he decided to pursue a career in mathematics, joined the University of Andhra and obtained the equivalent of a master’s degree before he was even 20 years old. Pressure from his family forced him to prepare for the Indian Civil Service Entrance Test (ICS).

While he had to wait around 18 months for the test, he decided to take a job and came to Calcutta to face an interview. A chance encounter with a young man, Mr. Subramanian, at a hotel in South India on this trip would change his life. Mr. Subramanian was training in statistics at the Indian Institute of Statistics (ISI). He took him to ISI, which was then in the physics department of Presidency College. Dr Rao joined ISI in 1941 as part of a training program. Her father had just passed away and there was financial stress in the family. However, his older brother and mother encouraged him to continue training at ISI.

“I didn’t learn much from classes” during the training program, said Dr Rao. However, he came into contact with three well-known statisticians, Raj Chandra Bose, Samarendra Nath Roy and Keshvan Raghvan Nair, all of whom worked at ISI, but were not involved in teaching. Less than three months after joining ISI, Dr Rao wrote his first scientific paper with Nair. In July 1941, while still a student in the one-year training program at ISI, the Masters in Statistics program was started at the University of Calcutta, with Prasanta Chandra Mahalanobis as the head of the department. statistics. This was the first statistics course in India. Dr Rao enrolled as a student and graduated in 1943 with a first rank, scoring 87.5 percent of marks, still a record at the University of Calcutta. While a master’s student, he published several articles with Raj Chandra Bose. His master’s thesis contained original contributions to several areas of statistics.

After graduating from her masters degree, Prasanta Chandra Mahalanobis offered Dr Rao a job at ISI as a technical apprentice in November 1943. In 1946 Mahalanobis sent Dr Rao to Cambridge to perform statistical analyzes of some data on skeletal material collected by JC Trevor. “The period from January 1944 to July 1946, before going to Cambridge, was perhaps the most eventful of my research career,” recalls Dr Rao. While teaching a statistics course at the University of Calcutta in 1944, he achieved a founding result with which his name is associated – the Cramer-Rao liaison.

In 1945 he proved a result which is now known as the Rao-Blackwell theorem. Often we have to acquire knowledge of an unknown characteristic of a population; for example, the average monthly income of Bengali. It is generally not possible to study all members of the population; it is not possible to collect data on the income of all Bengalis living all over the world. Data can only be collected from a small number of suitably selected Bengalis. From these data, one can then obtain an approximate knowledge, and not an exact estimate. There are several ways to obtain estimates from data, but the method proposed by Dr. Rao, and two years later by David Blackwell, results in very reliable estimates.

In Cambridge, Dr Rao enrolled for a doctorate with Ronald A. Fisher, a founder of modern statistical science. Fisher asked Dr. Rao to come up with his own problem to solve and write a doctoral thesis, and asked him to only seek his advice when he “ran into difficulty.” Fisher worked in the genetics department, not the statistics department. He asked Dr. Rao to spend time in the genetics lab. Fisher was trying to find out which genes were on which chromosomes in mice. Dr Rao did this and came up with a new method to determine how close two genes are physically. The method is named after him – the Rao score test – and is now used in all branches of science, both natural and social.

After submitting his doctoral thesis, Dr Rao returned from England to India in 1948 and became a professor at ISI at the age of 28. In 1964, he assumed the leadership of the ISI. After his retirement from ISI, he moved to the United States. In 1982, he established the Center for Multivariate Analysis at the University of Pittsburgh. He joined Pennsylvania State University in 1988.

Dr. Rao’s contributions to mathematics and statistical theory and applications are now part of graduate and postgraduate courses in statistics, econometrics, electrical engineering and many other disciplines at universities around the world. His fellowship has strongly influenced the theory and application of statistics in fields as diverse as anthropology, geology, biology, psychology, social science, and national planning. His work in multivariate analysis, for example, is used to improve economic planning, weather forecasting, medical diagnostics, tracking spy plane movements, and monitoring the course of spacecraft.

Dr Rao is the author or co-author of 14 books and over 300 research articles. His book *Linear statistical inference and its applications*, published in 1965, has been translated into six languages and has remained one of the most cited scientific books.

When I joined ISI as a B.Stat student. Of course in 1970, his presence was felt in every corner of the institute. As students, we were amazed. Such a famous person, but so modest, so sweet and so polite. He had a weird and subtle sense of humor. In his lectures, even on theoretical statistics, he always started by motivating the subject with a practical example. He has always stressed that statistical research, even on statistical theory, should largely result from 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 an expert committee. Statistics can shed more light than the collective wisdom of a few articulate people, ”he said.

Dr Rao has classified creativity into two different types. “At its highest level, it is the birth of a new idea or theory which is qualitatively different and not in accordance with or deductible from any existing paradigm, and which explains a larger set of natural phenomena than any theory. existing. There is another kind of creativity on a different level, a discovery made within an existing paradigm but of immense significance in a particular discipline.

Dr Rao excelled in the creativity of both types, which is why he is today the most respected statistician in the world.

*(Partha P. Majumder is National President of Science and President of Indian Academy of Sciences)*