Significance of the CPI 2023-24 Base Revision:
The CPI base revision updates the consumption basket and price weights to reflect contemporary household expenditure patterns. Over a decade-old, the previous series included outdated items like tape recorders and VCD players, which no longer represent current consumption behavior. By incorporating updated items, the CPI provides a more accurate measure of inflation that mirrors the actual cost of living for Indian households.
Policy relevance: CPI forms the basis for important policy decisions, including interest rate adjustments by the Reserve Bank of India, social welfare payments, and dearness allowance (DA) calculations for government employees. A more accurate CPI ensures that fiscal and monetary interventions are aligned with the economic realities experienced by consumers.
Example: The headline inflation rate for the revised CPI series stands at 2.75%, with slight differences between rural (2.73%) and urban (2.77%) areas. This updated series provides policymakers with robust, real-time information to formulate responsive economic strategies.

Need for revision:
The previous CPI series had a base year over 12 years old, resulting in an outdated representation of consumer spending patterns. As consumption behavior evolves, certain items lose relevance, while new goods and services emerge. Without revision, inflation metrics could misrepresent the actual cost of living, leading to suboptimal policy decisions.
Impact on policy and stakeholders: Accurate CPI measurement is crucial for determining dearness allowance (DA), pensions, and welfare benefits. Outdated indices could disadvantage both government employees and vulnerable populations. For example, industrial workers have historically resisted CPI changes for fear of reductions in DA, highlighting the sensitivity of CPI to socio-economic groups.
Forward-looking approach: The 2023-24 revision also accounts for digitisation trends, including e-commerce and OTT services, ensuring the CPI reflects modern consumption patterns and maintains relevance over the next five years until the subsequent base revision.

Methodology and data collection:
The revision process involved extensive consultation and coordination. The expert group, comprising academics, representatives from central ministries, and state governments, leveraged multiple data sources, including the Household Consumer Expenditure Survey (HCES) 2023-24 and market surveys. Physical markets were surveyed to identify popular products, and specifications were standardized for consistent monthly price collection.
Integration of administrative and alternative data: Ministries such as Railways, Petroleum & Natural Gas, and Civil Aviation, along with regulatory bodies like CERC, provided essential price data, which strengthened the comprehensiveness and timeliness of the index. These administrative inputs complemented household survey data, ensuring the CPI accurately captured both urban and rural consumption trends.
Adaptation to emerging consumption trends: Recognizing the rise of digital and e-commerce consumption, the expert group recommended incorporating online platforms into price collection, even where weightings were not precisely known. This proactive approach allows the CPI to remain representative of India's rapidly evolving consumption landscape.

Key challenges:

• Outdated consumption basket: The previous CPI included items no longer relevant to modern consumers.
• Data availability and reliability: The HCES 2023-24 survey was in progress during the revision, raising concerns about timely and accurate data collection.
• Treatment of PDS items: Free distribution under the Public Distribution System (PDS) posed methodological dilemmas, as CPI traditionally measures prices actually paid by consumers.
• Rapid digitisation: E-commerce and digital services were not fully captured in traditional surveys, necessitating new methods of data integration.

Examples of modernisation:

• Digital services: Consumption of OTT platforms and home-service aggregators like Urban Company was included, reflecting the growing importance of services in household expenditure.
• E-commerce transactions: Popular products sold online were identified through surveys, and prices were collected alongside traditional retail outlets to capture contemporary price dynamics.
• Administrative data: Monthly price information from Ministries like Railways, Petroleum & Natural Gas, and Civil Aviation supplemented survey data, ensuring comprehensive coverage.

Positive impacts:

• Provides an accurate and timely measure of inflation, enhancing monetary policy effectiveness.
• Ensures social welfare and DA payments are adjusted fairly, maintaining equity for different income groups.
• Improves data quality and analytical robustness, supporting evidence-based policy interventions.

• Short-term resistance from stakeholders like industrial workers concerned about DA adjustments.
• Initial integration of e-commerce and digital services may have approximations, as precise weightings are yet to be established.
• Reliance on administrative data requires strong inter-ministerial coordination to ensure consistency and timeliness.

Case Study:
During the CPI 2023-24 base revision, Mospi combined traditional survey data with modern administrative and alternative data sources. Household expenditure patterns were captured through HCES, while monthly price updates were sourced from ministries like Petroleum & Natural Gas, Railways, and Civil Aviation. Additionally, emerging consumption trends, such as e-commerce and OTT subscriptions, were included despite initial challenges in determining precise weightings.
Integration and benefits: This hybrid approach allowed the CPI to reflect both historical consumption habits and modern digital consumption behavior. For example, digital goods now account for a meaningful portion of urban household expenditure, which would have been underrepresented in a purely survey-based methodology.
Implication for policy: By leveraging multiple data streams, the CPI revision delivers timely and accurate inflation metrics that guide fiscal and monetary decisions, enhance social welfare targeting, and maintain credibility among stakeholders. It serves as a model for future index construction in a rapidly digitising economy.