Two Economists Looked at the Same GDP Number and Got Growth Rates 7.2 Points Apart

You Cannot Subtract Two Numbers From Different Rulers and Call It a Measurement Subhash Chandra Garg's

2.6% nominal growth claim and MoSPI's 7.8% real growth figure are not really a disagreement about India's economy - they are a disagreement about whether two numbers measured on different scales can be subtracted from each other at all.

Garg's calculation divided this year's nominal GDP (Rs 88.3 lakh crore, from the new 2022-23 base-year series) by last year's nominal GDP under the old 2011-12 base-year series (Rs 86.05 lakh crore). MoSPI's specific objection isn't that Garg did the arithmetic wrong - it's that dividing a number from Series A by a number from Series C, where the two series use different base years, different deflators and different methodology entirely, produces a number that describes nothing real.

It's the statistical equivalent of measuring a room in metres one day and feet the next, then reporting the "change" in room size.

What Double Deflation Actually Fixes

The old GDP series used "single deflation" for most sectors outside agriculture and mining - applying the same price index to both a sector's inputs and its outputs, even when input costs (raw materials) and output prices moved at very different rates.

The new series applies "double deflation" universally, using over 300 sector-specific Producer Price Index deflators instead of roughly 180 previously, deflating inputs and outputs separately before computing real value added.

This isn't a cosmetic upgrade - it's a methodology the IMF and international agencies had specifically flagged as a weakness in India's data for years and it mechanically produces different nominal GDP levels than the old series would have, entirely independent of any intent to flatter or deflate the growth rate.

The Number That Actually Settles This SBI's Soumya Kanti

Ghosh offers the comparison that should have ended the debate: if you insist on comparing across series, the only valid way is new-series-to-new-series - Rs 88.3 lakh crore (new base, released August) over Rs 80.4 lakh crore (new base, released June)

• which yields 9.7% nominal growth, translating to roughly 7.4% real growth even under a hypothetically adjusted deflator. That is close to the official 7.8% figure, not close to 2.6%. The 2.6% figure only exists because it deliberately mixes a new-series numerator with an old-series denominator.

Why the Corroborating Data Matters More Than Either Side's Framing

An economy genuinely growing at 2.6% nominal would not simultaneously show GST collections up 11%, passenger vehicle sales up 25.6%, tractor sales up 19%, exports up 17% and net FDI nearly doubling year-on-year. These aren't GDP methodology artifacts - they are independent, real-economy indicators that corroborate the 7.8% figure and directly contradict the near-stagnation implied by the disputed comparison.