Prasanta Chandra Mahalanobis was born in colonial India in 1893, and grew up within the intellectual tradition of the Brahmo Samaj reformist movement founded by Raja Rammohun Roy in Bengal.
a) Mahalanobis distance: His strong interest in minimizing errors in this field took him into multivariate analysis where he developed the D2 statistic, the Mahalanobis Distance. His interest in errors included errors of observation, errors of measurement and sampling errors.
b) Member of Planning Commission: As a member of planning commission, Prof. Mahalanobis came up with Two-sector Input-output model to be implemented during the Second Five Year Plan (1956-61), famously known as the Nehru-Mahalanobis model.
c) Establish ISI: Also as founder of the Indian Statistical Institute, he was substantially involved in scientifically designing the surveys for large-scale sample. With the help of this, he set up the National Sample Survey with the aim to collect data on various aspects of socio-economic parameters of the country.
d) Introduction of new concepts: The three notable contributions to the theory and practice of sample surveys by Mahalanobis are “pilot surveys, optimum survey design and Inter Penetrating Network of sub-samples technique (IPNS)”. He always advocated Inter penetrating network of sub-samples (IPNS) theory both in conduct of large scale sample surveys as well as in working of Government administration where he did not approve of the fact that it was regulated by principle of authority. Mahalanobis was very much concerned with errors at various stages of data collection and analysis and insisted on cross examination of data. He applied IPNS for assessment and control of errors, especially non-sampling errors, in surveys. His technique of IPNS was appreciated by both the statisticians as well as politicians. The concept of pilot surveys was a forerunner of sequential sampling developed by Abraham Wald, as acknowledged by Wald in his book.