Discuss the rationale and implications of revising India's CPI base year from 2012 to 2024. How does base-year revision affect inflation measurement and monetary policy?

The Consumer Price Index measures retail price change against a base period whose weights reflect household spending patterns. MoSPI's shift from 2012=100 to 2024=100, effective with the first release of 12 February 2026 [2], was a necessary statistical correction to an index that had drifted from how Indians actually consume.

Rationale for the revision

• Outdated weights: a decade of rising incomes shifted spending from cereals toward services and processed foods; new weights derive from the Household Consumption Expenditure Survey (HCES) 2023-24 [2].
• Basket obsolescence: the item basket widened from 299 to 358 items (goods 259→308, services 40→50), adding rural housing, streaming services and digital storage while dropping VCRs, DVD players and cassettes [2].
• Methodological credibility: base prices were collected across January–December 2024, aligned to the HCES reference period, under an Expert Group including RBI, academia and statistical experts [2].

Implications for inflation measurement

• Reweighting changes the headline number itself — a lower food weight dampens the transmission of food shocks into CPI, though CFPI at 5.52% against headline 4.45% in July 2026 shows food still dominates price pressure [1].
• Wider services coverage captures previously invisible inflation, seen in the spread from personal care at 14.77% to information and communication at 0.63% [1].
• Comparability breaks: pre- and post-2026 figures are not directly comparable, complicating long-run trend analysis and back-series construction.

Implications for monetary policy

• CPI anchors the RBI's flexible inflation targeting framework (4% ± 2%); a recalibrated index alters the MPC's read of where inflation sits within the band — July 2026's 4.45% remains comfortably inside it [1].
• Rural–urban divergence (4.84% vs 3.96%) and state variance such as Telangana at 6.32% [1] give the MPC finer texture for calibrating a uniform national rate.

Periodic base revision is thus not a technical formality but the foundation of credible inflation targeting. Institutionalising revisions at fixed intervals, with transparent back-series linking, would strengthen both statistical trust and evidence-based monetary policymaking.