Slutsky Equation Decomposition

The Slutsky equation is a fundamental concept in consumer theory that explains how a change in the price of a good affects a consumer's purchasing behavior.

Understanding Price Effect Decomposition

Specifically, the Slutsky equation decomposes the total price effect into two distinct components:

• Substitution Effect: This represents the change in the consumption of a good due to a change in its relative price, assuming the consumer's real income (purchasing power) remains constant. Consumers tend to substitute away from relatively more expensive goods towards relatively cheaper ones.
• Income Effect: This represents the change in the consumption of a good resulting purely from the change in the consumer's real income caused by the price change. If a price decreases, the consumer feels richer and may buy more (or less, for inferior goods). If a price increases, they feel poorer.

Slutsky Equation Representation

The equation shows that the total change in quantity demanded (the price effect) is the sum of the substitution effect and the income effect. While the substitution effect always works in the opposite direction of the price change (price up, substitution effect reduces quantity; price down, substitution effect increases quantity), the income effect can reinforce or oppose the substitution effect, depending on whether the good is normal or inferior.

Therefore, the Slutsky equation deals with the decomposition of the price effect into substitution and income effects.