Govt to hold talks on GDP, CPI, IIP base year revisions: what it means for the numbers

The government has kicked off a technical — but important — exercise to update how it measures the economy. On November 26, 2025, the Ministry of Statistics & Programme Implementation (MoSPI) is holding a consultative workshop in Mumbai to discuss proposed base-year revisions for three headline series: GDP, the Consumer Price Index (CPI) and the Index of Industrial Production (IIP). This is part of a larger move to make official statistics reflect today’s economy better.

Updating the base year isn’t just bureaucratic housekeeping. It changes the yardstick for growth and inflation, can shift historical growth rates when data are rebased, and affects how policymakers, businesses and markets read economic trends. Below I explain what’s happening, the timeline, and why GDP — our focus keyword — matters here.

Why the government is revising GDP, CPI and IIP base years

Bring statistics closer to today’s economy

Economic structures evolve: new industries emerge, consumption patterns shift, and digital transactions and GST data have become central. The current series use older base years (GDP and IIP were based on 2011–12, CPI on 2012), which can understate newer sectors and changing household spending. Rebasings align weights, samples and methods with recent surveys and administrative data.

Improve accuracy and international comparability

Revising base years allows MoSPI to use the latest Household Consumption Expenditure Survey (HCES) data, incorporate GST and digital data sources, and adjust industrial samples (for instance, removing permanently closed factories). These moves improve accuracy and help align India’s series with international best practice.

What are the proposed new base years?

• GDP: proposed to move from 2011–12 to 2022–23 (financial-year base).
• IIP: proposed to move from 2011–12 to 2022–23.
• CPI: proposed to move from 2012 to 2024 (calendar year base for the CPI series). The CPI reweighting will use items and weights from the HCES 2023–24.

These are the proposals that MoSPI has been consulting on — the November 26 workshop is explicitly a consultative step in finalising methodology and timelines.

Timeline — when will the new series appear?

Current public reporting from MoSPI and media indicates staged release dates in early 2026:

• CPI: new CPI series expected to be released on 12 February 2026. This series will use 2024 as a base (weights from HCES 2023–24).
• GDP: a new GDP series (base 2022–23) is scheduled for release on 27 February 2026. This will replace the 2011–12 series for national accounts.
• IIP: the revised IIP series (base 2022–23) is expected to roll out along with or soon after the GDP revision; some IIP outputs on the revised base are likely from the 2026–27 industrial year onward.

Note: these dates have been reported by MoSPI and major Indian outlets; final dates and formats are set by MoSPI and can be confirmed in its formal releases. The November 26 workshop is a live step in that process.

How rebasing can change GDP numbers and their interpretation

Short-term shocks vs structural change

When you change the base year, two things typically happen: (1) the weights used to aggregate industry and consumption categories change, and (2) some methodological improvements (sample replacement, new data sources) alter series composition.

As a result, historical GDP growth rates can be revised — sometimes upward, sometimes downward — without any actual change in the underlying economy. That’s because the benchmark (the base year level and composition) has changed.

Practical effects for users

• Policymakers: monetary and fiscal policy decisions rely on accurate inflation (CPI) and growth (GDP) signals. Rebased series may slightly change the view of output gaps and trend growth.
• Business and markets: analysts recalibrate models and forecasts based on the new series.
• Public communication: headlines might shift (“growth revised up/down”) even though the real economy is unchanged — so context matters.

Key methodological changes to watch

CPI — more frequent rebasing and updated basket

MoSPI has signalled it may update CPI weights more frequently (every 3–5 years) using triennial HCES rounds. That means CPI will better reflect changing consumption patterns going forward.

IIP — replacing closed factories in samples

The IIP proposals include replacing permanently closed or inactive factories with active units from recent surveys, using overlapping 12-month data for continuity. This reduces distortion from legacy samples and better captures current industrial structure.

GDP — integration of digital and administrative data

For GDP, MoSPI intends to integrate GST, corporate filings and other administrative/digital sources to improve the coverage of newer services and manufacturing activities. That improves estimates of the services sector — an important driver of GDP.

What readers and analysts should do now

• Treat short-term headline changes cautiously. If GDP growth figures are revised, read the methodological notes and revisions table MoSPI will publish.
• For forecasting or modelling, request the rebased historical series from MoSPI and rebuild trend/seasonal models on the revised data.
• Watch for sectoral reweighting: changes often matter most in services and newer industries (digital, e-commerce, platform services).

Bottom line — GDP and trust in statistics

Rebasing GDP, CPI and IIP is a positive step: it modernises measurement, uses fresh surveys, and adds administrative data. For the public and analysts, the immediate task is to read the revised series carefully — and avoid conflating statistical rebasing with a real-time change in economic performance.

The consultative workshop on 26 November 2025 is a public, technical step toward those revised series, and MoSPI’s announced release windows in February 2026 will be the moments when the new GDP, CPI and IIP series become the official reference points. If you follow economic news, pay attention to the MoSPI releases and the technical notes that explain the revisions in detail.

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