Professor C.R. Rao. Photo: Ministry of Parliamentary Affairs, GODL-India
More than at any time in the past, Indian science has enjoyed a remarkable few days in the limelight. Chandrayaan-3’s landing on the moon was hailed all over the world. Ironically, the success of the Chandrayaan, a homegrown initiative, happened in the same week as the death of the renowned statistician, C.R. Rao, at the age of 102. It is tempting to contrast one event as a beginning and the other as an end. But it might be perhaps more appropriate to celebrate the remarkable life and achievements of C.R. Rao. To look back at his life is to reiterate the validity of the scientific method as perhaps the most pragmatic way to chart our collective future, as a nation and as a planet. And in a time when the rigour of science has had to make way for half-baked theories and bizarre claims, Rao’s life and work are a beacon of inspiration.
Calyampudi Radhakrishna Rao was born on September 10, 1920 in Huvvina Hadagalli, which is now in Karnataka. His father, C. Doraswamy Naidu, was an inspector of police. His mother was A. Laxmikanthamma, whom Rao credits in an autobiographical fragment as someone who goaded him on to reach for the stars. Rao, it appears, was a precocious child. At the age of five, he memorised multiplication tables up to 16 by 16 (useful for monetary calculations then, when a rupee was 16 annas).
After initially studying in different schools in various parts of modern-day Andhra Pradesh, Rao did the later part of his schooling in Vishakapatnam – where the family had settled after his father’s retirement. He first took a BA (Hons) degree in mathematics from Andhra University as a top-ranked student and also obtained an MSc in mathematics. Around that time, a job interview took him to Kolkata, where he learned of the Indian Statistical Institute (ISI) whose courses he found attractive as they held some vague promise of a job when one finished them. As a student of mathematics, statistics was bound to have been reasonably familiar to Rao. But did he, at that point, have a special affinity for the subject? That he titled one autobiographical account ‘Statistics as a Last Resort’ should tell us where he stood.
Regardless, the programme at ISI seems to have triggered something in him. He took to research almost immediately, began publishing papers and obtained his MA in 1943 with marks so high that they still remain a record. A research scholar position at ISI and a part-time teaching job at Calcutta University soon followed.
In 1945, Rao wrote a seminal paper in the Bulletin of the Calcutta Mathematical Society. The results that he detailed in this paper are considered his seminal achievements. In April this year, when he was chosen for the International Prize in Statistics, the announcement specifically mentioned these three results: the Cramér-Rao lower bound, the Rao-Blackwell Theorem, and insights that pioneered a field known as ‘information geometry’.
In statistics, researchers are required to make estimates and inferences from the data collected. Two of Rao’s 1945 results, the Cramér-Rao lower bound and the Rao-Blackwell Theorem, are connected to the quality of such inferences. The Cramér-Rao lower bound allows a statistician to assess how accurate an estimate is. The Rao-Blackwell Theorem helps improve that estimate or as detailed by the International Prize in Statistics Foundation, the theorem ‘provides a means for transforming an estimate into a better — in fact, an optimal — estimate’. Independently, Swedish mathematician Harold Cramér and American statistician David Blackwell also established these results (hence their two-part name). Combined, the results help scientists extract information from data more efficiently and they paved the way for the modern field of statistics and provided the statistical tools heavily used in science today.
The Rao-Blackwell process has been applied to stereology, particle filtering, and computational econometrics, among others, while the Cramér-Rao lower bound is of great importance in fields such as signal processing, spectroscopy, radar systems, multiple image radiography, risk analysis, and quantum physics. Information geometry has in recent times aided the understanding and optimisation of Higgs boson measurements at the Large Hadron Collider besides finding applications in research on radars and antennas and contributing to advancements in artificial intelligence, data science, signal processing, shape classification, and image segregation.
Between 1946 and 1948, Rao did a stint at the Department of Anthropology, Cambridge University, where he was tasked with analysing the measurements being made on human skeletons. He also obtained a PhD from Cambridge during this time. By 1948, he was back at ISI and was soon appointed professor.
Over the next few decades, Rao worked in various positions at ISI – as the head of the Research and Training School (RTS), director of RTS, director of ISI, Jawaharlal Nehru Professor and National Professor. He developed a variety of courses to train statisticians to work in different areas. Students and trainees, deputed by research, government and industrial organisations to study at ISI, were given on-the-job experience in design of experiments, biostatistics, industrial quality control and other areas. Rao established research units to work on projects in subjects such as economics, sociology, psychology, genetics, anthropology, geology and others. Rao also initiated programmes leading to the BStat and MStat degrees besides establishing the PhD programme in theoretical statistics and probability.
Under P.C. Mahalanobis, Rao assisted in establishing the State Statistical Bureaus. The Indian National Statistical System, with the Central Statistical Organisation and State Statistical Bureaus, is considered to be one of the best in the world, thanks to Mahalanobis and Rao. He also served as a member of several government committees for the development of national statistical systems, statistical education and research in India.
By the time of his retirement at age 60, Rao had become something of a giant in the field. He then moved to the US – primarily because professorships with minimal teaching responsibilities were offered to him, which would allow him to continue his research. He worked first at the University of Pittsburgh and later at Pennsylvania State University. After retiring from Penn State at 81 (he continued as Emeritus Professor), he held a position as a Research Professor at the University at Buffalo. The US stint saw him produce 274 papers, while all his years in India had produced 201. Clearly, research was his calling and he flourished in an atmosphere that encouraged pure research sans administrative responsibilities.
Like ISRO’s Chandrayaan, Rao was a product of Indian institutions. The Andhra University and the ISI nurtured him in his youth and in time, he returned the favour. He was also involved with the creation of a number of other institutions and programmes which were instrumental in contributing to various facets of Indian administration. His life story is therefore much more than a story of an inspirational figure in science. His life underlines the importance of building, nurturing and conserving institutions – of all sorts – owing to the depth of their contribution to the nation in times past and the many possibilities of their continued presence in the future. His hugely productive stint in the US is a pointer to how many Indian institutions need to be pivoted. It is the lack of understanding of the role of institutions and the need for investing in them consciously that is under threat in India today.
Karthik Venkatesh is a publishing professional who writes on literature, language, history and politics. He is deeply interested in Indian science and scientists.