UPSC Mains 2021 GS Paper 3 Q1: model answer
Explain the difference between computing methodology of India’s Gross Domestic Product (GDP) before the year 2015 and after the year 2015.
What the question wants
Explain how India's GDP methodology changed with the series released in 2015.
How to structure it
Explain the difference: old versus new series.
- What changed in 2015
- Key differences
- The debate
- Later developments
How to think it through
In January 2015 the CSO moved the base year from 2004–05 to 2011–12, made GDP at market prices the headline, used GVA at basic prices for sectors, and used the MCA-21 corporate database. Mention the overestimation debate. Note the new series of February 2026 with base year 2022–23.
Model answer
In January 2015 the Central Statistics Office released a new GDP series with base year 2011–12, replacing 2004–05. Growth numbers changed overnight, and so did the way GDP was built.
Before 2015
- Headline growth was GDP at factor cost.
- Manufacturing estimates leaned on the Index of Industrial Production.
- An establishment approach: each factory or unit counted separately.
After 2015
- Headline growth became GDP at market prices; sector output is measured as GVA at basic prices.
- The MCA-21 database of company filings replaced IIP-based estimates for the corporate sector.
- An enterprise approach: a company counted as a whole, including head-office and marketing activity.
- Wider coverage of services and alignment with the UN System of National Accounts, 2008.
The debate
Some economists argued that the new series overstated growth; the government disputed this. Concerns centred on deflators and MCA-21 sampling.
Since then
MoSPI released a new series with base year 2022–23 on 27 February 2026, refreshing the data sources again.
The 2015 change made India's accounts more modern and comparable; the debate shows that credibility matters as much as method.
Draw: Two columns: 'pre-2015' versus 'post-2015' with four rows (base year, headline, data source, approach).
Keywords, cases and data to drop in
base year 2011–12, GVA at basic prices, GDP at market prices, MCA-21, enterprise approach, SNA 2008, deflator debate, base year 2022–23 (2026).
Where most answers lose marks
- Saying only 'the base year changed'. The method and data sources changed too.
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Question text as printed in the official UPSC Civil Services (Main) question paper. The model answer is original Battle IAS work; use it to learn structure, not to memorise.
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