Context: A former Finance Secretary questioned the official Q1 FY 2026-27 GDP growth estimates of 7.8% in real terms and 10.3% in nominal terms, suggesting substantially lower growth.
- However, the criticism incorrectly combines old-series and new-series GDP estimates, making the proposed growth calculation statistically invalid.
- Nevertheless, the sharp downward revision in nominal GDP under the new national accounts series raises a legitimate question about data reconciliation and transparency.
Why the Initial Growth Calculation Is Flawed
- Under the old series, Q1 FY 2025-26 nominal GDP was ₹86.05 lakh crore, whereas the new 2022-23-base-year series puts it at roughly ₹80 lakh crore.
- Calculating growth using the old-series denominator and new-series numerator mixes incompatible statistical series and therefore produces a meaningless growth rate.
- The Ministry of Statistics and Programme Implementation (MoSPI) is therefore correct in rejecting such a calculation.
- However, rejecting an invalid growth calculation does not eliminate the need to explain the large revision in the underlying GDP estimates.
Scale of the GDP Revision
- Under the old 2011-12-base-year series, nominal GDP was ₹86.05 lakh crore in Q1 and ₹85.25 lakh crore in Q2 FY 2025-26, giving a first-half total of ₹171.30 lakh crore.
- Under the new 2022-23-base-year series, both Q1 and Q2 are estimated at approximately ₹80 lakh crore, reducing the first-half estimate by around ₹11 lakh crore or 6.5%.
- The revision is particularly significant because the old series was discontinued before comparable Q3 and Q4 FY 2025-26 estimates became available.
- Consequently, there is no complete old-series annual estimate against which the new series can be reconciled quarter by quarter.
Why a Base-Year Change Does Not Explain Everything
- A new national accounts series can legitimately revise historical estimates because it incorporates new data sources, wider coverage, improved indicators and methodological changes.
- However, changing the base year from 2011-12 to 2022-23 primarily affects the measurement of real GDP, which is expressed at constant prices.
- Nominal GDP is measured at current prices, so the base-year change alone cannot explain a substantial decline in nominal GDP estimates.
- The downward revision may have valid statistical explanations, but their individual contributions need to be quantified and disclosed.
What MoSPI Should Disclose
- MoSPI should publish a reconciliation bridge showing, in rupee terms, how the old Q1 and Q2 estimates were transformed into the new estimates.
- The bridge should separately quantify the impact of revised source data, changes in sectoral coverage, methodological revisions, tax/subsidy estimates and price-related changes.
- The same reconciliation should be provided for Gross Value Added (GVA) to identify whether particular sectors account for a disproportionate share of the revision.
- Major components such as manufacturing, trade, financial services and agriculture should be shown separately wherever they materially contribute to the change.
Revision vs Loss of GDP
- A downward statistical revision does not mean that the economy actually lost ₹11 lakh crore of output.
- It means that the statistical system has re-estimated the size of economic activity using a revised methodology and/or better information.
- Historical GDP revisions are a normal feature of national accounting and can move estimates either upward or downward.
Overall Growth Picture
- Despite the revision in the level of nominal GDP, cumulative nominal GDP growth between 2022-23 and 2025-26 remains broadly similar: around 32.8% under the old series and 32.3% under the new series.
- Cumulative real GDP growth is also broadly comparable, although the new methodology produces a somewhat lower estimate.
New National Accounts Series
- National accounts revisions update the measurement framework by incorporating new base years, improved datasets, broader coverage, updated methodologies and revised price/volume measures.
- Such revisions improve the relevance of GDP estimates by better reflecting the current structure of the economy.
- The credibility of a revised GDP series therefore depends not only on the methodology but also on transparency regarding revisions and their underlying sources.
Real vs Nominal GDP
- Nominal GDP measures economic output at current prices and reflects both changes in production and prices.
- Real GDP measures output after removing the effect of price changes, enabling comparison of actual changes in production.
- Therefore, nominal GDP growth and real GDP growth answer different economic questions and should not be conflated.
Way Forward
- Publish detailed old-series-to-new-series reconciliation tables for GDP and GVA at quarterly and annual levels.
- Make underlying methodological changes and major data sources sufficiently transparent to allow independent scrutiny and replication.
- Clearly distinguish between statistical revision of economic estimates and actual changes in economic activity.
- Independent verification and transparent documentation can strengthen public confidence without compromising the NSO's statistical methodology.
Conclusion: The debate demonstrates that both methodological correctness and statistical transparency matter. Critics cannot derive valid growth rates by mixing incompatible GDP series, while the government cannot adequately address legitimate concerns by attributing every major revision merely to a change in base year. Credible official statistics require numbers that independent researchers can understand, reproduce and interrogate.
