Q.Distinguish between consumer price index and the GDP deflator any three points.
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The GNP Deflator: From Everyday Intuition to Exam-Ready Concept
Imagine you earn ₹50,000 a month. Next year, your salary goes up to ₹55,000 — a 10% raise. Are you actually better off? Not if the price of everything you buy has also risen by 10%. Your nominal income went up, but your real purchasing power stayed the same.
This is exactly the problem the GNP Deflator solves — but for an entire country's output instead of your salary.
What the GNP Deflator Actually Measures
The GNP Deflator is a price index that measures the average change in prices of all final goods and services included in the Gross National Product (GNP). Unlike the Consumer Price Index (CPI) which tracks only a fixed basket of consumer goods, the GNP Deflator covers everything a country's residents produce — including machinery, government services, exports, and capital goods.
The GNP Deflator is not based on a fixed basket. It uses the current year's composition of output. This means it automatically accounts for new goods and changing consumption patterns — something the CPI cannot do.
The Formula (NCERT Standard)
The NCERT textbook defines the GNP Deflator as:
GNP Deflator=Real GNPNominal GNP×100
Where:
- Nominal GNP = GNP measured at current year prices (includes inflation)
- Real GNP = GNP measured at base year prices (removes inflation)
- The multiplication by 100 converts it into an index number
How It Works: A Step-by-Step Example
Suppose India produces only two things in a year: wheat and steel.
Step 1: Calculate Nominal GNP
Use current year prices × current year quantities for everything.
Step 2: Calculate Real GNP
Use base year prices × current year quantities for everything. This shows what the same output would have cost if prices hadn't changed.
Step 3: Apply the formula
If Nominal GNP = ₹120 lakh crore and Real GNP = ₹100 lakh crore, then:
GNP Deflator=100120×100=120
This means the general price level has risen by 20% since the base year.
Why It Matters (and Where It Differs from CPI)
The GNP Deflator serves three critical purposes in macroeconomics:
- Converting nominal to real values — If you know the deflator, you can "deflate" any nominal GNP figure to find real GNP:
Real GNP=GNP DeflatorNominal GNP×100
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Measuring economy-wide inflation — The percentage change in the GNP Deflator from one year to the next gives the inflation rate for all domestically produced goods and services.
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Comparing across time — Without the deflator, comparing India's GNP in 1990 to 2024 would be meaningless because prices have changed so much.
A common exam mistake: The GNP Deflator includes exports (since GNP includes what residents produce abroad) but excludes imports (since imports are not part of domestic production). CPI, by contrast, includes imported consumer goods. This is why the two indices can give different inflation rates.
The Key Insight NCERT Expects You to Know …
The consumer price index and the GDP deflator are both price indices but differ in coverage and base. …
CPI = fixed consumer basket (includes imports); GDP deflator = all domestic output (variable basket).
| Basis | Consumer Price Index (CPI) | GDP Deflator |
|---|---|---|
| Coverage of goods | A fixed basket of goods and services consumed by households | All final goods and services produced within the economy |
| Nature of basket/weights | Based on a fixed basket with fixed weights (base-year quantities) | The basket changes with the composition of current output (variable weights) |
| Imported goods | Includes imported goods purchased by consumers | Excludes imports; includes only domestically produced goods |
| … |
- CBSE 2026Set ANNUAL1 markQ.Write the answer in one sentence: What is inflation?
›Reveal solutionSolution
Inflation = a sustained rise in the general price level, reducing money's purchasing power.
Inflation is a situation in which there is a sustained and continuous rise in the general price level of goods and services in an economy over a period of time. As prices rise, the purchasing power of money falls. It is measured by price indices such as the Wholesale Pri …
- CBSE 2025Set MARCH1 markQ.CPI - Expand.
›Reveal solutionSolution
CPI stands for Consumer Price Index.
The Consumer Price Index (CPI) measures the average change over time in the prices of a fixed basket of goods and services commonly consumed by households. It is a key indicator of the cost of living an …
- CBSE 2023Set MARCH1 markMCQQ.The ratio of Nominal GDP to real GDP is(a) Consumer Price Index(b) Wholesale Price Index(c) Producer Price Index(d) GDP Deflator
›Reveal solutionSolution
Nominal GDP ÷ Real GDP is the GDP deflator, a broad measure of the price level.
Why:
- Nominal GDP is valued at current prices; real GDP is valued at base-year (constant) prices. …
- CBSE 2023Set ANNUAL1 markQ.Answer in one sentence: What is inflation?
›Reveal solutionSolution
Inflation = a sustained rise in the general price level, reducing money's purchasing power.
Inflation is a situation in which there is a sustained and continuous rise in the general price level of goods and services in an economy over a period of time. As prices rise, the purchasing power of money falls — the same amount of money buys fewer goods than before. Mild inflation may accompany growth, but high inflation hurts fixed-income groups and distorts the economy. It is me …
- CBSE 2023Set ANNUAL1 markMCQQ.Meaning of deterioration in the purchasing power of money is :(a) Decrease in prices of goods(b) No change in the prices of goods(c) Rise in prices of goods(d) None of these(a) Decrease in prices of goods(b) No change in the prices of goods(c) Rise in prices of goods(d) None of these
›Reveal solutionSolution
Falling purchasing power of money = rising prices (inflation); the two move in opposite directions.
Purchasing power of money is inversely related to the general price level: if the price level rises (inflation), a fixed amount of money (say ₹100) can buy fewer goods and services than before — its purchasing power has fallen, or 'deteriorated'. Conversely, a fall in the general price level (deflation) would IMPROVE the purchasing power of money, as the same ₹100 could buy more goods. 'No change in prices' would leave p …
- CBSE 2022Set MARCH1 markMCQQ.The ratio of nominal GDP to real GDP is(a) Consumer Price Index(b) Wholesale Price Index(c) GDP Deflator(d) Producer Price Index
›Reveal solutionSolution
Nominal GDP divided by Real GDP gives the GDP Deflator (option c).
…
- CBSE 2020Set 58/2/11 markQ.A car purchased by a household is a _________ . (Choose the correct alternative) (A) single use capital good (B) single use consumer good (C) durable consumer good (D) semi-durable consumer good(OR)GNP deflator is represented by which of the following formulae ? (Choose the correct alternative) (A) (Nominal GNP / Real GNP) × 100 (B) (Real GNP / Nominal GNP) × 100 (C) (Real GNP / Change in Rate of Inflation) × 100 (D) (Change in Rate of Inflation / Real GNP) × 100
›Reveal solutionSolution
Part (a): a household car lasts for years and is for personal use → durable consumer good (C). Part (b): GNP deflator = (Nominal GNP / Real GNP) × 100 → (A).
Part (a)
Classify a good by who uses it and why and how long it lasts.
- A car bought by a household is used for personal transport, directly satisfying wants → a consumer good (a car bought by a firm for a taxi service would be a capital good).
- A car serves repeatedly over many years → durable, unlike single-use goods (food) or semi-durable goods (clothing). …
- CBSE 2020Set ANNUAL1 markQ.Answer in one word/sentence: Write the utility of Index Number.
›Reveal solutionSolution
Index numbers measure changes in prices/quantities over time and act as economic barometers.
An index number is a statistical device that measures the relative change in a variable (such as price, quantity or value) between two periods. Its utility (uses):
- It measures changes in the price level and helps gauge inflation/deflation and the cost of living.
- It acts as an 'economic barometer' indicating the state of economic activity.
- It helps in framing economic policies and in wage/salary adjustment (dearness allowance). …
- CBSE 2019Set 58/3/11 markQ.According to a report forwarded by the Reserve Bank of India, there was a fall in rate of inflation as measured by Consumer Price Index (CPI) on year-on-year basis to 5% from 8% in the previous year. Which of the following statements represents the situation?(a) CPI has fallen(b) CPI has risen at a rate lower than the preceding year(c) CPI is constant(d) None of the above
›Reveal solutionSolution
The question is about the rate of change of CPI, not its absolute level. A fall in the inflation rate from 8% to 5% means prices are still rising, but more slowly. The correct statement is that CPI has risen at a rate lower than the preceding year — option (b).
The key concept here is the difference between level and rate of change. The Consumer Price Index (CPI) is a measure of the average price level. Inflation is the percentage change in CPI from one year to the next. So when the report says "inflation fell from 8% to 5%", it means the CPI is still increasing — just at a slower pace.
A common mistake is to confuse a fall in the inflation rate with a fall in the price level itself. That would be deflation, which is not what's described.
Let's break it down step by step.
-
Understand what the numbers mean.
Last year, CPI inflation was 8%. That means the CPI at the end of last year was 8% higher than at the end of the year before. This year, CPI inflation is 5% — so the CPI now is 5% higher than it was at the end of last year.
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Compare the two years.
The CPI is still rising (since 5% is positive), but the rise is smaller than last year's 8% rise. So the CPI is increasing, but at a lower rate.
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Evaluate each option.
- (a) CPI has fallen — This would mean the CPI is lower than last year, i.e., negative inflation (deflation). That's not the case here. …
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