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Income Effect vs. Substitution Effect: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on November 8, 2023
The Income Effect describes how consumption changes due to purchasing power shifts, while the Substitution Effect explains consumption changes from altered relative prices.

Key Differences

The Income Effect encompasses the change in consumption patterns resulting from a change in real income or purchasing power. In contrast, the Substitution Effect delves into the alteration in consumption as relative prices of goods change, making one product more appealing than another.
When the price of a good falls, the consumer can buy the same quantity of that good and still have money left over, leading to a rise in real income and thus the Income Effect. On the other side, the Substitution Effect will indicate that the good has become relatively cheaper, causing the consumer to buy more of it and less of its substitute.
Observing the Income Effect, a decline in the price of a normal good (keeping everything else constant) will generally increase its quantity demanded. The Substitution Effect, independent of income considerations, will also lead to an increase in demand for the good that has become comparatively cheaper.
It's possible, especially with inferior goods, for the Income Effect to work in the opposite direction of the Substitution Effect. For example, if the price of an inferior good drops, the Substitution Effect will lead to higher demand, but the Income Effect might reduce demand if consumers feel richer and opt for superior alternatives.
Economists use the concepts of Income Effect and Substitution Effect to understand consumer behavior. While both effects result from price changes, the Income Effect reflects changes in real income and resultant consumption shifts, and the Substitution Effect focuses on relative price changes and the consequent adjustments in consumption patterns.

Comparison Chart


Deals with changes in real income or purchasing power.
Concentrates on changes in relative prices of goods.


Caused by changes in the purchasing power of money.
Caused by a change in the relative prices of goods.

Outcome for Normal Goods

When the price drops, demand typically increases.
When the price of a good falls, it becomes more appealing than its substitute.

Interaction with Inferior Goods

Might decrease demand if price drops due to increased real income.
Will increase demand for the good that becomes cheaper, regardless.

Analytical Use

Helps understand changes in consumption from income variations.
Aids in understanding why consumers might shift preference between goods.

Income Effect and Substitution Effect Definitions

Income Effect

The Income Effect denotes changes in demand due to shifts in real income.
After a salary raise, Lisa bought more organic foods, demonstrating the Income Effect.

Substitution Effect

It aids in predicting how consumption adjusts to market price dynamics.
The decrease in soda consumption with rising prices demonstrated the Substitution Effect.

Income Effect

It essentially captures the consumer's ability to buy.
Economic downturns often depress luxury markets, a manifestation of the Income Effect.

Substitution Effect

It's independent of income changes, focusing solely on price variations.
When a brand of cereal became cheaper than its competitor, the Substitution Effect was at play.

Income Effect

It can lead to increased or decreased demand, contingent on the good's nature.
The price drop in a staple food saw higher sales, a clear Income Effect.

Substitution Effect

It occurs when one good becomes more or less attractive relative to a substitute.
A surge in electric car sales after gas price hikes evidenced the Substitution Effect.

Income Effect

For inferior goods, the Income Effect may reduce demand with increased real income.
When canned soups went on sale, some opted for fresh alternatives due to the Income Effect.

Substitution Effect

It drives consumers to favor goods that offer better relative value.
The popularity of streaming over traditional TV subscriptions highlighted the Substitution Effect.

Income Effect

It highlights consumption alterations stemming from purchasing power variations.
Due to inflation, John bought fewer luxury items, an outcome of the Income Effect.

Substitution Effect

The Substitution Effect pertains to shifts in demand due to changes in relative prices.
With beef prices rising, many switched to chicken, showcasing the Substitution Effect.


How do economists utilize these concepts?

Economists use the Income Effect and Substitution Effect to predict and understand consumer responses to price and income changes.

How does the Substitution Effect influence consumer behavior?

The Substitution Effect describes how consumers change their preferences between products due to relative price shifts.

Which effect is solely based on price changes?

The Substitution Effect is purely based on relative price changes, while the Income Effect considers real income shifts.

What does the Income Effect represent?

The Income Effect represents how changes in real income or purchasing power affect consumption patterns.

Can the Income Effect be negative for some goods?

Yes, for inferior goods where an increase in real income may lead to reduced demand.

Can the Income Effect and Substitution Effect work in opposing directions?

Yes, especially with inferior goods where a price decrease might boost demand via the Substitution Effect but reduce it via the Income Effect.

Are these effects observable in everyday scenarios?

Absolutely. Daily purchasing decisions often involve both the Income and Substitution Effects.

Why might the Substitution Effect be more prominent for close substitutes?

Close substitutes are easily interchangeable, so consumers quickly switch based on relative prices, emphasizing the Substitution Effect.

How do subsidies impact these effects?

Subsidies reduce the effective price, potentially triggering both the Income and Substitution Effects.

Do both effects always lead to the same consumption outcome?

Not necessarily. Depending on the good and the situation, the effects might lead to different consumption outcomes.

How do these effects behave with luxury goods during an economic boom?

The Income Effect would likely increase demand for luxury goods, and the Substitution Effect would depend on relative luxury good prices.

How do sales and discounts play into these effects?

Sales can trigger the Substitution Effect if one product becomes relatively cheaper, and boost real income, influencing the Income Effect.

Does inflation influence the Income Effect?

Yes, inflation reduces real income and can depress demand, reflecting the Income Effect.

Are there goods unaffected by these effects?

Essential goods might show minimal effects, especially if there are no substitutes.

Do these effects operate in all markets?

They primarily operate in consumer markets, but principles can be extrapolated to other contexts.

Is the Income Effect always dominant?

Not necessarily. The dominant effect depends on various factors, including the nature of the good and the size of price or income changes.

What's the connection between these effects and utility?

Both effects derive from the utility maximization principle, where consumers aim to get the most value.

How do external shocks, like pandemics, impact these effects?

Such shocks can drastically alter real income and relative prices, intensifying both the Income and Substitution Effects in various markets.

How does the Substitution Effect react to brand loyalty?

Brand loyalty can diminish the Substitution Effect, as consumers stick to preferred brands despite price changes.

Can technology advancements influence the Substitution Effect?

Yes. As technology makes some products obsolete, consumers switch to newer alternatives, reflecting the Substitution Effect.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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