WPI, CPI, Core Inflation — Core Concepts

Core Concepts

India uses three key inflation measures: WPI (Wholesale Price Index), CPI (Consumer Price Index), and Core Inflation. WPI measures wholesale price changes across 697 items with base year 2011-12, heavily weighted toward manufactured goods (64.

23%) and primary articles (22.62%). CPI measures retail price changes across 299 items with base year 2012, including food and beverages (45.86%), services through miscellaneous category (28.32%), and housing (10.

07%). Core inflation excludes volatile food and fuel components from CPI to show underlying price trends. RBI shifted from WPI to CPI-based inflation targeting in 2016 because CPI better reflects consumer welfare and includes services.

The inflation target is 4% (+/- 2%) based on CPI. WPI and CPI often diverge due to different compositions - WPI excludes services and has lower food weightage. Core inflation helps monetary policy by filtering out supply-side price shocks that don't require interest rate intervention.

Key data sources: NSO compiles CPI, Office of Economic Adviser compiles WPI. Understanding these differences is crucial for UPSC as questions test ability to explain divergent trends and policy implications.

Important Differences

vs GDP Deflator

Aspect	This Topic	GDP Deflator
Coverage	WPI: 697 items, CPI: 299 items, Core: CPI minus food & fuel	All goods and services in GDP calculation
Price Level	WPI: Wholesale prices, CPI: Retail prices	Average prices of all domestic production
Base Year	WPI: 2011-12, CPI: 2012	Changes with GDP base year (currently 2011-12)
Services Inclusion	WPI: No services, CPI: Services included	All services in domestic production included
Policy Use	CPI used for inflation targeting, WPI for trade policy	Used for real GDP calculation and broad price trends

GDP deflator is the broadest inflation measure as it covers all domestically produced goods and services, while WPI and CPI have specific baskets. GDP deflator reflects price changes in production, WPI reflects wholesale market prices, and CPI reflects consumer prices. For monetary policy, CPI is preferred over GDP deflator because it directly relates to consumer welfare and spending patterns.

vs Types of Inflation

Aspect	This Topic	Types of Inflation
Measurement Focus	Measures price level changes through indices	Classifies inflation by causes (demand-pull, cost-push, etc.)
Policy Application	Used for quantitative inflation targeting and monitoring	Used for understanding inflation causes and appropriate policy response
Time Dimension	Provides monthly/quarterly inflation rates	Analyzes short-term vs long-term inflation patterns
Sectoral Analysis	Shows which sectors contribute to inflation	Explains whether inflation is supply-driven or demand-driven
International Comparison	Allows comparison of inflation rates across countries	Helps compare inflation characteristics and policy responses

WPI, CPI, and Core Inflation are measurement tools that quantify inflation, while types of inflation classify inflation by its underlying causes and characteristics. The measurement indices tell us 'how much' inflation exists, while inflation types tell us 'why' inflation exists. Both perspectives are essential for comprehensive inflation analysis and policy formulation.

Also build Paper II skills

Regional comparisons and process chains train the same coherence and inference habits CSAT passages demand. CSAT hub.

• Data interpretation
• Estimation techniques
• Logical deductions