Context
The Ministry of Statistics and Programme Implementation (MoSPI) has revised historical GDP estimates under the new 2022–23 base-year series, with greater use of double deflation and the Producer Price Index (PPI). The changes have revised some past growth figures and raised the importance of improving the accuracy and comparability of GDP estimates.
Understanding Real GDP and Deflation
1. Nominal GDP measures output at current prices, so its growth reflects both changes in production and prices.
Formula: Current Prices × Current Quantities
2. Real GDP/GVA measures growth after removing the effect of price changes, giving a better picture of actual economic activity.
Formula: Current Quantities × Base Year Prices
3. In national accounts, deflation means adjusting nominal values to remove the impact of price changes. It is different from economic deflation, which means a general fall in prices.
4. The GDP deflator measures the price change associated with all domestically produced final goods and services and helps convert nominal GDP into real GDP.
Formula: GDP Deflator = (Nominal GDP / Real GDP) × 100
Shift from Single to Double Deflation
- GVA measures the value created by a sector: GVA = Output − Intermediate Consumption.
- Earlier method — Single Deflation: The same price deflator was generally applied to both output and inputs. This could distort real GVA when input and output prices changed at different rates.
- New method — Double Deflation: Output and intermediate consumption are deflated separately using appropriate price indices. Thus, Real GVA = Real Output − Real Intermediate Consumption.
- Example: Understanding Double Deflation
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- A factory produces goods worth ₹200 crore using inputs worth ₹100 crore. Hence, GVA = ₹100 crore.
- If output prices rise by 4% while input prices rise by 10%, using one common deflator can give a distorted result.
- Double deflation adjusts them separately: real output = ₹200 crore and real inputs = ₹100 crore.
- Therefore, real GVA = ₹200 − ₹100 = ₹100 crore, showing that the change in nominal values was mainly due to price changes, not higher production.
5. Why it matters: It better captures the impact of changing input costs and output prices, improving the measurement of real GVA and economic growth.
Greater Use of Producer Price Index (PPI)
- Producer-level prices: PPI measures prices received by producers, generally closer to the factory-gate price.
- Less distortion: It excludes price effects from taxes, transport costs and trade margins, making it more suitable for GDP deflation.
- Better sectoral measurement: The new series uses over 300 sector-specific deflators, compared with around 180 earlier, allowing more accurate adjustment of output and input prices.
Why the Change Matters for Services
- WPI limitation: WPI mainly tracks goods prices, so it does not adequately capture service-sector price changes.
- Better cost capture: Sector-specific price measures can better reflect changes in wages, rents and other service-related costs.
- More accurate growth: Better price adjustment helps distinguish actual growth in services from growth caused by changes in prices.
- Improved GVA measurement: More sector-specific deflators strengthen the measurement of real services GVA.
Negative Deflator in Manufacturing
- Meaning: A negative deflator occurs when nominal GVA growth is lower than real GVA growth. It does not mean that production is falling.
- Why it occurs: It can arise when output prices fall or rise more slowly than input prices.
- Manufacturing trend: Manufacturing has recorded negative implied deflators in several quarters under the new GDP series.
- Role of input costs: Rising crude-oil and other input costs may not be fully passed on to consumers because of competition or limited pricing power, causing output prices to rise less than input prices.
Significance
- Better growth measurement: Separate adjustment of input and output prices gives a more accurate estimate of real GVA.
- Improved sectoral analysis: Sector-specific deflators provide a clearer picture of manufacturing and services.
- Better policymaking: More reliable GDP estimates support sound monetary, fiscal and development policies.
- Stronger national accounts: Improved price adjustment enhances the quality and reliability of GDP data.
- Clearer growth picture: It helps distinguish actual production growth from changes caused by prices.
Challenges
- Limited PPI coverage: Input-side PPI is still developing and is mainly available for manufacturing.
- Sectoral data gaps: Adequate sector-specific price data are not available for all sectors.
- Methodological complexity: Using different deflators across sectors makes GDP estimation more complex and data-intensive.
- Revision concerns: Changes in methodology and data sources can lead to revisions in historical GDP estimates.
Way Forward
- Expand PPI coverage: Extend PPI to more sectors, especially services.
- Improve data quality: Strengthen the availability of timely price and production data.
- Update price indices: Regularly revise sectoral weights and price indices to reflect economic changes.
- Ensure transparency: MoSPI should provide clear sources, methods and estimation details.
- Strengthen review: Periodically evaluate the GDP methodology to improve the credibility and reliability of national accounts.
Additional Information:
| Feature | Wholesale Price Index (WPI) | Producer Price Index (PPI) |
| What it measures | Change in wholesale prices of goods | Change in prices received/paid at the producer level |
| Base Year | 2022–23 | 2022–23 |
| Published by | OEA, DPIIT* | OEA, DPIIT |
| Frequency | Monthly | Monthly; services quarterly |
| Services covered? | No | Yes |
| Main components | Manufactured Products (~64%),
Primary Articles (~23%), Fuel & Power (~13%) |
Output PPI, Input PPI and Service PPI |
| Main use | Tracks wholesale price trends and support price adjustment | Tracks producer-level price changes and can signal future price pressures |
* Office of Economic Adviser (OEA), Department for Promotion of Industry and Internal Trade (DPIIT), Ministry of Commerce & Industry
FAQs
Q1. What is double deflation?
Ans: It is a method in which output and intermediate consumption are deflated separately using appropriate price indices. It provides a more accurate estimate of real GVA.
Q2. How is GDP deflation different from economic deflation?
Ans: GDP deflation is a statistical process of removing price changes from nominal values. Economic deflation refers to a sustained fall in the general price level.
Q3. Why is PPI useful for GDP estimation?
Ans: PPI captures prices received by producers, generally closer to factory-gate prices. It provides a more appropriate measure for adjusting producer-side output and input values.
Q4. Why can a negative GDP deflator occur?
Ans: It occurs when nominal growth is lower than real growth. This can happen when output prices fall or rise more slowly than input prices.
Q5. What is GVA?
Ans: Gross Value Added measures the value created by an economic sector. It is calculated as value of output minus intermediate consumption.
Q6. What is Gross Domestic Product (GDP)?
Ans. GDP is the total money value of all final goods and services produced inside a country’s borders during a specific time, usually one year.
