There’s no one to fill Mahalanobis’s shoes

There’s no one to fill Mahalanobis’s shoes

By, Atanu Biswas is Professor of Statistics, Indian Statistical Institute, Kolkata

Context

* In Poverty and Famines (1981), Amartya Sen argued that poor distribution of food, wartime inflation, speculative buying and panic hoarding were important reasons for the devastating Bengal famine of 1943.

Survey of the Bengal famine

* Prasanta Chandra Mahalanobis, India’s ‘Plan Man’ and the architect of the country’s statistical system, conducted a large-scale sample survey of Bengal’s famine-ravaged villages between July 1944 and February 1945 for causal analysis, and to assess the extent of the disaster and an estimate of the number of people affected.

* The planning, preparations, challenges and findings of the survey are documented in an article in Sankhy?, and in another article in The Asiatic Review, both published in 1946, among others.

* This survey provided very useful findings. It showed that one-fourth of the number of families (1.5 million people) who had owned rice land before the famine had either sold in full or in part their rice land or had mortgaged it.

* It also showed that the economic position of nearly four million people deteriorated during the famine.

* Economic differences became further accentuated during the famine. However, roughly 85% of the families maintained their status quo, showing that a large degree of economic inertia had persisted even under famine conditions.

* Bengal’s famine survey reminds us that we need estimates of the millions who will lose jobs or livelihoods and of the hundreds of millions whose economic conditions will deteriorate in today’s COVID-19-hit India.

* Mahalanobis is perhaps more relevant today when the accuracy of different sorts of data — from economic data to COVID-19 data — is under the scanner.

* Starting from the first area sample in the whole world for jute forecast in 1934, Mahalanobis built up a strong and trustworthy statistical heritage in India through his tireless efforts over the years, supplemented by his efficiency, wisdom, leadership, innovative ideas and brilliance.

* Mahalanobis envisaged large-scale sample surveys as statistical engineering rather than pure theory of sampling.

* He was instrumental in establishing the National Sample Survey (NSS) in 1950 and the Central Statistical Organization in 1951.

Importance of accurate data

* Mahalanobis was very careful about data accuracy in his surveys. In Kautilya’s Arthashastra, there is mention of the need for cross-checking by an independent set of agents for data collection: “Spies under disguise of householders (Grihapatika, cultivators), who shall be deputed by the Collector-General for espionage, shall ascertain the validity of accounts (of Gopas, the village officers and Sthanikas, the district officers) regarding the fields, right of ownership and remission of taxes with regard to houses, and the caste and profession regarding families...” (Chapter XXXV).

* This might have prompted Mahalanobis to have an independent supervisory staff during the conduct of field operations by the NSS for collection of reliable data.

* Mahalanobis was “a physicist by training, a statistician by instinct and an economist by conviction”.

* His initial training in Physics might have made him conscious about errors in measurement and observation. Students even called him the Professor of Counting and Measurement, using the initials of his name.

* The desire to have built-in cross-checks and to get an estimate of errors in sampling led him to introduce the Inter-Penetrating Network of Subsamples, which is now considered as the curtain-raiser for re-sampling procedures like Bootstrap, a revolutionary concept of statistics indeed.

* First, even in pre-COVID-19 India, it’s widely reported that surveyors were facing tremendous resistance from people due to some sociopolitical reasons.

* None other than Pronab Sen, Chairman of the Standing Committee on Economic Statistics, and former Chief Statistician, expressed his concern that the survey system is already in “deep trouble”, and conducting household surveys with the Census as the frame would be “very tough” going ahead.

* The problem will intensify due to COVID-19. It was not easy to conduct surveys in famine-hit Bengal either.

* Through August 1944, 80 field workers were beset by malaria; half of them later dropped out of the project.

Use of technology

* Note that Mahalanobis never shied away from technology, whether in bringing statistical technology through volumes of Biometrika in his voyage from England, or even bringing computers to India.

* The Mahalanobis-led Indian Statistical Institute procured India’s first computer in 1956 and the second in 1959.