Editing Inferior good (section)

=== Substitution effect ===
The substitution effect is the effect that a change in relative prices of substitute goods has on the quantity demanded. It due to a change in relative prices between two or more substitute goods. When the price of a commodity falls and prices of its substitutes remain unchanged, it becomes relatively cheaper in comparison to its substitutes. In other words, its substitutes become relatively costlier. Consumers would normally like to substitute cheaper goods for costlier ones. Thus, the demand for relatively cheaper substitute commodities increases.<ref>{{Cite book |last=Sethi |first=D.K |title=ISC Economics |publisher=Macmillan |isbn=9789386811684 |edition=18th |page=19}}</ref> Compared to normal goods, a price decrease (or increase) would actually decrease (or increase) the consumption of an inferior good. This is only possible if negative income effect is strong or large enough to outweigh the substitution effect.<ref name=":1" />