Inferior good

Topic: Consumer Behaviour, Demand and Elasticity · NCERT: Class 12, Ch 2 "Theory of Consumer Behaviour"

Meaning

An inferior good is a good whose demand falls when the consumer's income rises, and rises when income falls, if other things stay the same. Its demand moves in the opposite direction to income.

• In the language of the price effect, its income effect is negative. When its price falls and real income rises, the buyer wants less of it.
• Income elasticity of demand (how strongly demand reacts to a change in income) = % change in quantity demanded ÷ % change in income. For an inferior good this is less than zero.
• Why it matters: this idea separates ordinary goods from Giffen goods. It also explains why demand for low-quality staples such as coarse cereals falls as Indian households get richer. That has effects on food policy, procurement and crop planning.

Explanation

How it works: the income test

• A good is classified as normal or inferior by how its demand responds to income, not to its own price.
• Normal good: income rises → demand rises. Most goods are normal.

• Inferior good: income rises → demand falls.

• Why buyers cut demand as income rises:

• A poor household buys a cheap, low-quality good because it cannot afford anything better.
• When income rises, it can afford a better substitute.

• So it moves away from the cheap good. Example: moving from coarse cereals to rice or wheat.

• A change in income shifts the whole demand curve. It is not a movement along the curve.

• For an inferior good, higher income shifts the demand curve to the left.

A good can change type as income changes

• "Inferior" is not fixed. It depends on the household's income level.
• Coarse cereal example:
• A very poor household's income rises from a very low level. It buys more coarse cereal to eat enough. Here, coarse cereal is a normal good.

• After a certain income level, the household switches to better cereals such as rice or wheat. Coarse cereal now becomes an inferior good.

• So the same good can be normal for one household and inferior for a richer one.

What happens when its price changes: substitution vs income effect

• A price change has two parts:
• Substitution effect: the change in quantity caused only because the good is now cheaper or dearer than other goods. The consumer's satisfaction is held at the same level. When the price falls, this effect always raises quantity, for every type of good.

• Income effect: the change in quantity caused by the change in real income (purchasing power) that comes from the price change [2].

• Total price effect = substitution effect + income effect.

• For an inferior good, the two effects pull in opposite directions:
• Price falls → the good is cheaper than other goods → buy more (substitution effect, +).

• Price falls → real income rises → buy less of the "poor man's" good (income effect, −).

• Worked example (price falls; the numbers are only an illustration):

Type of good	Substitution effect	Income effect	Total effect	Law of demand?
Normal	+ 4 kg	+ 2 kg	+ 6 kg	Holds strongly
Inferior (not Giffen)	+ 4 kg	− 1 kg	+ 3 kg	Holds weakly
Giffen	+ 2 kg	− 5 kg	− 3 kg	Violated

• Reading the table:
• In an ordinary inferior good, the substitution effect is larger. Quantity still rises when price falls. The demand curve still slopes downward, but less strongly.
• If the negative income effect becomes larger than the substitution effect, the good becomes a Giffen good, and the demand curve slopes upward.

When is an inferior good likely to become Giffen?

• The good is strongly inferior.
• It takes up a large share of the budget.
• It has few close substitutes.
• The buyers are very poor.
• Key rule: all Giffen goods are inferior goods, but not all inferior goods are Giffen goods.

In India

• Coarse cereals are the NCERT (Class 12) example of an inferior good. As incomes rise, households move to rice and wheat.
• Household Consumption Expenditure Survey (HCES) data from the statistics ministry shows how the income–consumption link works:
• Average MPCE (monthly per capita consumption expenditure, meaning average household spending per person per month) in 2023-24 was ₹4,122 in rural areas and ₹6,996 in urban areas. This excludes items received free through welfare schemes [3].
• Food's share of spending in 2023-24 was 47.04% (rural) and 39.68% (urban) [3].
• Between 2011-12 and 2022-23, the food share fell from about 53% to 46% (rural) and from about 43% to 39% (urban) [4].

• As incomes rose, households moved from starchy cereals towards higher-value, more nutritious foods [4][5].

• What this means: cereals behave like a necessity, and some low-quality cereals behave like inferior goods. Demand for them grows slowly or falls as income rises.

• Millets push: campaigns such as the International Year of Millets rebrand coarse cereals as nutritious, higher-value food. The aim is to change tastes, so that millets stop behaving like inferior goods.

Don't confuse with

• Giffen good: a special inferior good whose negative income effect is larger than its substitution effect, so demand rises when price rises. An ordinary inferior good still follows the law of demand.
• Normal good: demand moves in the same direction as income, so its income effect is positive. An inferior good's income effect is negative.
• Veblen good: a luxury or status good bought by the rich. Its demand rises with price because a high price signals prestige. This is about preferences, not a negative income effect. An inferior good is a cheap good bought by the poor.
• Necessity: demand rises with income, but less than proportionately, so income elasticity is between 0 and 1. For an inferior good, income elasticity is below 0.

Prelims Hooks

• An inferior good has a negative income effect and negative income elasticity of demand. Its demand falls as income rises.
• For a price fall, the substitution effect always raises quantity demanded, even for inferior and Giffen goods.
• Trap: "All inferior goods are Giffen goods" is false. "All Giffen goods are inferior goods" is true.
• An ordinary inferior good obeys the law of demand, because its substitution effect is larger than its income effect.
• The same good can be normal at low income and inferior at higher income. Example: coarse cereals (NCERT Class 12).
• HCES 2023-24: food's share of spending was 47.04% (rural) and 39.68% (urban) [3].

Mains Points

• Changing diets and farm policy: the food share fell from about 53% to 46% (rural) and about 43% to 39% (urban) between 2011-12 and 2022-23 [4].
• Households are moving away from cereals, and some cereals behave as inferior goods.
• This supports crop diversification towards pulses, dairy and horticulture.

• It also warns against over-procurement of rice and wheat.

• Food subsidies for the very poor: when a staple behaves as a strongly inferior good, cutting its price can lead poor households to buy less of it and more of other foods (Jensen–Miller 2008, rice in Hunan, China).

• So PDS-type price subsidies may end up funding a more varied diet rather than more grain.

• Nutrition policy should look at the whole diet, not only the amount of cereal eaten.

• Millets and the inferior-good tag: coarse cereals lose demand as incomes rise.

• Branding millets as healthy, premium food tries to shift tastes.
• If this works, demand for millets could rise with income, which would help farmers in dry areas and improve nutrition.

Related concepts

• Law of demand
• Substitution effect
• Income effect
• Normal good
• Giffen good
• Veblen good
• Conspicuous consumption
• Bandwagon effect
• Snob effect
• Demonstration effect

Read more

• Law of demand, substitution and income effects, normal/inferior/Giffen goods and exceptions