Discuss the rationale and significance of periodically revising the base year of macroeconomic indices such as IIP, GDP and WPI in India.

Q. Discuss the rationale and significance of periodically revising the base year of macroeconomic indices such as IIP, GDP and WPI in India. (15 marks, 250 words)

A base year is the reference point against which economic change is measured. As India's industrial and consumption structure evolves, an outdated base distorts reality — prompting MoSPI to shift the IIP, GDP and WPI series to a common 2022-23 base [1][2], the 10th such IIP revision since 1937 [1].

Rationale for revision - Structural change: new products, services and sectors emerge; the old 2011-12 IIP basket of 109 item groups no longer mirrored the economy, now expanded to 234 [3]. - Wider coverage: the revised IIP adds Gas Supply and Water Supply, Sewerage & Waste Management to the Mining-Manufacturing-Electricity trio [1][3]. - Normal-year benchmark: 2022-23 was chosen as it reflects broadly normal conditions, free of COVID-era distortions [4]. - Updated weights: sectoral weights are re-derived from GVA shares (current prices) per National Accounts, keeping the index representative [3].

Significance - Accuracy: finer granularity improves the reliability of high-frequency growth signals feeding GDP estimation and RBI's rate decisions. - Harmonisation: aligning IIP, GDP and WPI to a single 2022-23 base reduces methodological mismatch across indices [4]. - Governance & credibility: expert-led revision via the Technical Advisory Committee (TAC-IIP) [2] reflects a consultative, transparent statistical process, strengthening data trust. - Policy relevance: better-measured industrial performance sharpens targeting of schemes and structural reforms.

Periodic base-year revision is thus essential statistical hygiene. Institutionalising a fixed revision cycle, as recommended for national statistics, would keep India's macro-data credible and globally comparable.

(~250 words)

Sources: 1. MoSPI FAQs — IIP New Series Base Year 2022-23 (PIB, PRID 2265637) — base shift 2011-12→2022-23, 10th revision, expanded sectoral coverage 2. Report of the Technical Advisory Committee on Base Year Revision of All-India IIP (PIB, PRID 2264966) — TAC-IIP expert-led revision process 3. FAQ for new IIP series with base year 2022-23 (MoSPI) — item groups 109→234, GVA-based weights, added utility sectors 4. Report of the TAC on Base Year Revision of IIP (MoSPI) — 2022-23 as normal-year base, harmonisation with GDP and WPI