Mahalanobis model

The Mahalanobis model is the economic-planning framework devised by Prasanta Chandra Mahalanobis, founder of the Indian Statistical Institute (ISI, established 1931) and statistical adviser to the Cabinet, which provided the analytical foundation for India's Second Five-Year Plan (1956–61). Building on a four-sector and a more famous two-sector model published in Sankhyā (1953) and elaborated in 1955, Mahalanobis argued that the long-run growth rate of an economy is determined by the proportion of investment allocated to the capital-goods sector rather than the consumer-goods sector. By concentrating investment in industries that produce machines—the "machines that make machines"—the economy would expand its future capacity to invest, accelerating growth. The model echoed the Soviet Feldman growth model (G.A. Feldman, 1928) and aligned with the Nehruvian commitment to a self-reliant, planned, mixed economy embodied in the Industrial Policy Resolution of 1956, which reserved core industries for the public sector.

Mechanically, the model divides the economy into a sector producing investment goods and a sector producing consumption goods, with the share of investment going to the capital-goods sector (the parameter λk) being the key policy lever. A higher allocation depresses immediate consumption but raises the economy's terminal capacity to produce capital, generating compounding growth. The strategy therefore justified large public-sector investment in steel, heavy machinery, coal, power and machine tools—giving rise to the public-sector "temples of modern India" such as the Bhilai, Rourkela and Durgapur steel plants, Heavy Engineering Corporation at Ranchi, and Bharat Heavy Electricals. The model deliberately accepted import substitution, capital intensity and deferred consumption, and it complemented the Harrod-Domar framework that had informed the First Plan (1951–56).

The Second Plan, drafted under the Planning Commission (created by Cabinet resolution, 1950, with Jawaharlal Nehru as chairman) and formally adopted in 1956, operationalised the model. Its limitations soon surfaced: neglect of agriculture and consumer goods aggravated food shortages and inflation, foreign-exchange crises emerged by 1957–58, and employment generation lagged because of capital intensity—criticisms voiced by economists including C.N. Vakil and P.R. Brahmananda, whose rival "wage-goods" model stressed consumer-goods and labour-intensive growth. The model's statist, inward-looking orientation persisted until the liberalisation reforms of 1991. As of 2026 the framework is studied as a historical paradigm: the Planning Commission itself was replaced by NITI Aayog on 1 January 2015, ending the era of centralised five-year planning.

For the UPSC examination the Mahalanobis model is a recurring theme in both the Indian Economy section of General Studies Paper III and the post-independence consolidation / economic history portion of General Studies Paper I. Candidates should be able to link it to the Second Five-Year Plan, contrast it with the Harrod-Domar and Vakil-Brahmananda wage-goods models, and critically evaluate its consequences for agriculture, foreign exchange and employment. Typical question angles ask candidates to assess whether the heavy-industry strategy was appropriate for a labour-surplus economy, or to trace the evolution of Indian planning from 1951 to NITI Aayog. Knowing the named authority, the precise plan period and the rival critique earns the marks.