History & Culture

Multi-faceted Prasanta Chandra Mahalanobis, the subject of today’s Google Doodle

Professor P. C. Mahalanobis.   | Photo Credit: The Hindu Archives

Google, on Friday, honoured Indian scientist, mathematician and statistician Prasanta Chandra Mahalanobis with a colourful doodle on the 125th anniversary of his birth. The doodle reflected what the scientist is best known for - the ‘Mahalanobis Distance’ — a measure of comparison between two different data sets.

However, the Mahalanobis Distance — his D2-statistic — is just the tip of the iceberg. Widely regarded as the father of statistics in India, Mahalanobis founded the Indian Statistical Institute (ISI), was handpicked by former Prime Minister Jawaharlal Nehru to shape the Planning Commission and basically pioneered methodologies for large-scale surveys. His years of work is regarded as the golden period of statistics in India by his students and peers.

Early life with physics

P.C. Mahalanobis, as he is often to referred to as, was born in Calcutta on June 29, 1893. He was educated at the Brahmo Boys School, founded by Raja Ram Mohan Roy and went on to receive a B.Sc in Physics from Presidency College, Kolkata. He followed this by going to the University of Cambridge where he studied both Physics and Mathematics.

On his return to India, Mahalanobis took up a teaching position in the physics department at Presidency College, and eventually became the Principal of the college till his retirement in 1948.

Of anthropology and statistics

Mahalanobis’ interest in anthropology started when he was at Cambridge, where he was introduced to the concepts of anthropometry (the study of measurements and proportions of the human body) and anthropological data through Biometrika, a peer-reviewed scientific journal. From there, it was just a hop, skip and jump into the world of statistics and the application of the science in anthropology.

“The papers in Biometrika dealing with biological and anthropological data had an immediate influence on Mahalanobis,” writes Somesh Dasgupta, in an edition of Sankhya: the Indian Journal of Statistics that was begun by Mahalanobis himself. “Besides being actively interested in statistical problems relating to agriculture, meteorology, and education, Mahalanobis was also deeply involved in questions relating to racial mixture, racial origins and the assessment of group differences,” Mr. Dasgupta writes.

Prof. P. C. Mahalanobis, President of the National Institute of Sciences of India, admitting PM Jawaharlal Nehru as a Fellow of the Institute, at its general meeting held in Delhi on Tuesday, January 20, 1959.

Prof. P. C. Mahalanobis, President of the National Institute of Sciences of India, admitting PM Jawaharlal Nehru as a Fellow of the Institute, at its general meeting held in Delhi on Tuesday, January 20, 1959.   | Photo Credit: The Hindu Archives

In the 1920s, Mahalanobis was asked to analyse the anthropometric measurements of Anglo-Indians in Calcutta. “This was the first time that data relating to a true biologically mixed population were studied by statistical methods,” Mr. Dasgupta writes.

According to the ISI, nearly all the major statistical work done in India till the 1930s was done single-handedly by Mahalanobis. “Some of the findings of these early studies were of great impact on the control of floods, agricultural development et al, and led to the recognition of statistics as a key discipline,” says the website.

The Indian Statistical Institute

The Indian Statistical Institute (ISI) was founded in December 1931 in Kolkata, with annual expenditure of less than Rs. 250. The ISI was the result of a workshop that was already located in his room at the Presidency College. The ISI had students that included mathematicians like C. R. Rao, G. Kallianpar, S. K. Mitra, K. R. Parthasarathy and S.R.S. Varadan among others.

“Mahalanobis’s influence was so pervasive that the students of Physics began to take interest in Statistics, the most notable of them having been Subhendu Sekhar Bose,” according to a primer on Mahalanobis by the ISI.

The ISI, under Mahalanobis, would go on to do some of the most spectacular large-scale survey and data analyses including assessing the impact of the 1942-43 Bengal famine, tabulating the 1941 census, surveys on rural indebtedness, tea-drinking habits, road development, velocity of circulation of rupee coins, family budgets, traffic flow, crop yield estimation etc.

The road to planning

In fact, it was the ISI’s work on crop yield estimation that attracted the attention of then Prime Minister Jawaharlal Nehru who would then go on to ask Mahalanobis to whip the Planning Commission into shape after Independence.

“He never studied traditional economic theory, and he believed that his lack of formal education in economics enabled him to work on the economic problems of the country with a sense of realism,” wrote his student and mathematician C.R. Rao in a 1993 edition of Current Science, celebrating Mahalanobis’ centennial birth anniversary.

Mahalanobis played a key role in formulating the Second Five-Year Plan, which is synonymous with the ‘Mahalanobis model’, also known as the Feldman-Mahalanobis Model. The basic idea of the model said that in order to increase domestic consumption, there needed to be an investment in the production of capital goods.

Many hats and multiple honours

Mahalanobis held and juggled multiple positions in his latter years. He was the honourary statistical advisor to the Indian Government from 1949 - a post he held until his death in June 28, 1972, a day before his seventy-ninth birthday. He was the head of the statistics department in Calcutta University from 1941 to 1945 and the statistical advisor to the government of Bengal from 1945-1948.

He was also a member of the United Nations Sub-Commission on Sampling since it was formed in 1949 and served as its Chairman from 1947 to 1951. He was made Honorary President of the International Statistical Institute in 1957, and was elected a Fellow of the American Statistical Association in 1961. He was also the president of the Indian Science Congress in 1949-50.

The mathematician was conferred several honours worldwide. He received an Order of the British Empire in 1942 and a Padma Vibhushan in 1968. He also received the Srinivasa Ramanujan Gold Medal in the same year. Interestingly, Mahalanobis struck up a close friendship with Ramanujan himself while they were both in England.

Former Prime Minister Manmohan Singh, in 2006, named June 29 as National Statistics Day in honour of Mahalanobis.

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Printable version | Jan 17, 2022 3:36:02 AM | https://www.thehindu.com/society/history-and-culture/the-many-hats-of-prasanta-chandra-mahalanobis-the-subject-of-todays-google-doodle/article24287515.ece

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