Key Terms & Concepts — UPSC Mains
GDP Base Year
"The reference year against which all subsequent GDP is measured, with its prices treated as constant (=100)"
A GDP base year is the benchmark year used in national accounts to calculate real (inflation-adjusted) economic output. Prices in the base year are indexed at 100, and real GDP growth in subsequent years is computed relative to this benchmark. Over time, consumption patterns shift, new industries emerge, and relative prices change — making the base year outdated and necessitating periodic revision. The National Statistical Commission (NSC) recommends revising the base year every five years. India shifted its GDP base year from 2011-12 to 2022-23 on February 27, 2026, incorporating methodological improvements including double deflation, the Supply and Use Table (SUT) framework, and HCES 2022-23 data.
A high-frequency UPSC topic for both Prelims and GS-3 Mains. UPSC tests the rationale behind base year changes, key methodological shifts (single vs. double deflation), institutional bodies involved (MoSPI, NSO, ACNAS), and the impact on fiscal ratios (fiscal deficit-to-GDP, debt-to-GDP). The 2026 revision is particularly significant as it reduced India's nominal GDP by 3.3%.
- 1 Base year prices are treated as constant (=100) for measuring real GDP
- 2 NSC recommends revision every 5 years; gap between 2011-12 and 2022-23 was 11 years
- 3 India has revised base year seven times since Independence (1948-49 to 2022-23)
- 4 The 2022-23 revision introduced double deflation and SUT framework for the first time
- 5 Nominal GDP under new series is approximately 3.3% smaller than old series
On February 27, 2026, MoSPI released the new GDP series with base year 2022-23. FY24 real GDP growth was revised sharply from 9.2% (old series) to 7.2% (new series) due to the adoption of double deflation in manufacturing.
