I was talking the other day," said William Rogers to the
other villagers gathered around the inn fire, 'to a gentleman about the place called Louvain, what the Germans
have burnt down. He said he knowed it well - used to
Wait a Belgian friend there. He said the house of his
P*nd was in a long street, numbered on this side, one,
hpo, three, and so on, and that all the numbers on one
side of him added up exactly the same as all the numbers
an the other side of him. Funny thing that! He said he
Awtv there was more than 50 houses on that side of the
street, but not so many as 500. I made mention. of the
matter to our parson, and he took a pencil and worked
~W the number of the house where the Belgian lived. I
dont know how he done it.
Perhaps the reader may like to discover the number of
that house.
THIS PUZZLE, written in the working-class dialect in the
Britain of the time, appeared in the December 1914 issue
of Strand magazine. As you will discover if you try to
solve the problem, the solution is not so easy. The
answer is House No 204 in a street of 288 houses.
But finding out this answer took only a few minutes
for P C Mahalanobis, then studying physics at King's
College, Cambridge, after switching from mathematics.
Maha'lanobis then took the problem to his mathematician
friend Ramanujam, who noted that if the 50-500 limit on
houses is removed, there can be several answers.
Ramanujam. then came up with a single
continued fraction that provided all the
answers.
The anecdote speaks volumes for both
men, who were close friends at Cambridge.
.Prasanta Chandra Mahalanobis was
born in Calcutta on June 29, 1893, into a
family that hailed from Panchasar village,
now in Bangladesh. The family's original
surname was Bandyopadhyaya but
switched to Mahalanobis, which was
conferred on the family by the Muslim
nawab. In 1854, Prasanta's grandfather
left Panchasar for Calcutta in search of a
livelihood.
Prasanta studied at the Brahmo Boys'
School and Presidency College in Calcutta,
graduating with honours in physics in
1912. A year later, he went to Britain to
study in London, but was so impressed
during a visit to Cambridge by King's
College Chapel that he decided to study in
Cambridge instead.
That was the first of two chance elements that shaped his future. The second
was a vacancy for a physics teacher at
Presidency College in Calcutta, which came
up when Mahalanobis returned to India for
a vacation. He had intended to go back to
Britain and do research at Cavendish
Laboratory, but he tookup the Presidency
College post instead as a temporary assignment. He became so engrossed in his work
in India, however, this never happened.
Mahalanovis' interest in statistics was
fostered by 1@is reading of the journal
Biometrika aid Karl Pearson's Biometrik
Tables. Wherib he was criticised for abandoning physics for statistics, Mahalanobis
explained it.Atistics would be a "key technology" in plaianing the economic develop-
ment of independent India, because statistics represents the "arithmetic of human welfare".
The Indian tradition does not stress
accuracy in figures, which explains to some
extent why the number of soldiers who
fought at Kurukshetra or the age of important characters in the Hindu epics are generally exaggerated. Historically, the Indian
belief,is that precision in figures has no significance and that the larger the number the greater its respectability.
Mahalanobis' contribution to the development of statistics in India needs to be
viewed against this background. He propounded a new approach to figures through
his writing on statistics and his responsibilm
ities -at the Indian Statistical Institute (11SU
and the Central Statistical Organisatioa
(CSO), both of which he helped to set up.
ISI was launched in 1931; the Indian jour-
nal of statistics, Sankhya, in 1933; the
National Sample Survey (NSS) in 1950, and
in 1941, Mahalanobis was instrumental in
forming a statistics section at the Indian
Science Congress.
The statistical laboratory that would
later evolve into ISI was initially part of the
physics department at Presidency College,
which Mahalanobis headed. He was also
honorary secretary of the laboratory from
its formation in 1931 until his death on
June 28, 1972. While a professor at
Presidency College, Mahalanobis pioneered
certain statistical techniques that were used
for a jute sample survey in Bengal. This led
eventually to the formation of the National
Sample Suivey.
The launching of CSO was extremely
important in the development of a statistical system in independent India. Then honorary statistical adviser to the cabinet, a
post specially created for him in 1949 by
Prime Minister Jawaharlal Nehru,
Mahalanobis was responsible for India
becoming an elected member of the UN
Statistical Commission.
Mahalanobis wa's the dominant figure at
ISL and referred to always as "Professor".
His word was law within ISI and in his
later years, some of the younger faculty
members began to reAnt his authority and
especially his insistence that faculty members had to obtain his permission to attend
outside seminars.
Mahalanobis became embroiled in a
controversy with the Indian Council of
Agricultural Research when he demanded
all statistical work in India had to be centralised at ISI in Calcutta, regardless of the subject.
In his later years at ISI, Mahalanobis'
interest shifted from pure statistics to economic planninSkand the Second Fiveear
Plan is associated with him. The two-sector
growth model developed by him and published in Sankhya in 1953, argued for a
shift in industrial investments to capital.
goods industries. A similar model was
developed in the Soviet Union at about the
same time.
The question of determining the precise
choice of investments that would go into
the capital goods industries, Mahalanobis
answered by developing a four-sector
model, which he published in Sankhya.
The Mahalanobis model was perfunctory
and did not employ the linear programming techniques that were fairly wellknown at ISI. This drew a lot of criticism.
In hindsight, however, certain characteristics of the Mahalanobis model seem
quite remarkable. First, it treated savings as
an exogenous variable, which means they
were not explained in terms of the
behavioural characteristics of households.
Perhaps this reflected his training as a
physicist, as economists building growth
models start with a savings function postulate. Second, the model was autarkic: (selfsufficient) and set in a closed economy.
And, third, the model assumed the government could control consumption completely. The second and third characteristics are
understandable, given Mahalanobis' socialist background.
In 1955, Mahalanobis became a. fullfledged member of the P.1anning
Commission and retained his membership
until 1967, serving occasionally as chairperson.
In a paper published in Sankhya in
1957, Mahalanobis traced the origin
of qualitative statistical thinking to the system of logic developed in the 4th century by the Jain philosopher Bhadrabahu.
Mahalanobis was particularly interested in
the multi-valued logic evolved by the Jains.
In a 1933 editorial in Sankhya, he asserted
evidence existed in Kautilya's Arthashastra
showing administrative statistics had
reached a high level of organisation in
ancient India. He noted also that although
written much later, Abul Fazl's Ain-i-
Akbari is fundamentally a statistical
compilation.
The three over-riding interests in
Mahalanobis' life were ISI and statistics,
his close relationship with Rabindranath
Tagore and the Brahmo Samaj, a reformist
@.Hindu group that evolved a dogma in
which Western intellectual rationalisation
and Christian philosophical and theological strands were interwoven with Hindu
tenets.
Mahalanobis attended Brahmo meetings
regularly. He garnered funds industriously
on the group's behalf, organised its board of
trustees in Delhi and was a liberal patron of
promising Brahmo youngsters.
Mahalanobis was devoted to his wife,
Nirmal Kumarl, daughter of a noted
Brahmo Samaj member named Heramba
Maitra, and though they had no children,
whenever they were apart, they would
write to each other every day.
The Mahalanobis home was named
Amrapali by, Tagore and though
Mahalanobis was neither student nor teacher at Santiniketan, he was a frequent visitor to Tagore's famed institution near Calcutta.
When Visva Bharati was set up in 1921.
Mahalanobis became one of its secretaries.
Mahalanobis went to the US in 1971 on
a lecture tour. On his return, he fell ill.
Early next year his condition deteriorated
and he underwent abdominal surgery in
May. He died on June 28.
In his obituary on Mahalanobis, the
founder of the statistics department at the
University of California in Berkeley, Jerzy
Neyman wrote, "P C Mahalanobis was not
just a professor of statistics, as there are
thousands of them all over the world.
Mahalanobis did more. He tried to do
something effective about the problems discussed."
What better tribute can there be?
---Bibek Debroy is a professor at the Indian
Institute of Foreign Trade, New Delhi.
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