A robust price index regime is the backbone of credible monetary policy. Examine in light of recent rebasing of WPI/CPI/GDP series to 2022-23.

Under the RBI Act (amended 2016), the Monetary Policy Committee is legally mandated to target CPI inflation at 4±2%. A credible policy therefore rests entirely on price indices that measure inflation accurately and currently — the very rationale for the ongoing rebasing to 2022-23.

Why a sound price index underpins monetary policy

• Repo-rate decisions turn on measured inflation; a biased index misprices the entire economy and erodes MPC credibility.
• The decade-old 2011-12 basket underweighted services, digital trade and green energy, distorting inflation and GDP-deflator readings.
• WPI/PPI feed real-growth and output-gap estimates that guide the policy stance.

How the 2022-23 rebasing strengthens the backbone

• The revised WPI expands the basket from 697 to 957 items, reclassifies crude petroleum, and adds solar, wind and nuclear power — mirroring the current economy [1].
• Launch of Output, Input and Service PPIs (7 services incl. banking, insurance, telecom) captures ex-factory producer prices and aligns India with IMF best practice, improving cross-country comparability [1][2].
• Synchronised rebasing of CPI, GDP and IIP to 2022-23 enhances coherence across the indicators the MPC reads together [3].

Caveats

• CPI, not WPI, is the target; PPI reform aids diagnostics, not direct targeting.
• A 5-year parallel run with PPI is needed to avoid contract-escalation and data discontinuity.

Rebasing sharpens the informational backbone of monetary policy. Completing the PPI transition and institutionalising periodic rebasing will further anchor MPC credibility and macroeconomic stability.