Shift vs Movement: the Central Distinction — Supply | IGCSE Economics

Exam Frequency Analysis

Past paper frequency (2018 to 2024)

This topic accounts for approximately 18% of your exam marks.

stable

Very High

Stable18%

Supply appears alongside demand on virtually every paper; cost changes, technology, and taxes/subsidies are the most tested supply shifters.

	Movement along the supply curve	Shift of the supply curve
What changes?	The good's own price	Any non-price factor (costs, technology, taxes, subsidies, number of firms, expectations, other-good prices, weather)
What does the curve do?	Stays put	Moves to a new position
What do we call the change?	Extension (price ↑) or contraction (price ↓)	Increase in supply (rightward) or decrease in supply (leftward)
What changes on the diagram?	The point on the curve	The whole curve
Vocabulary	"change in quantity supplied"	"change in supply"

Example — Distinguish a movement along a supply curve from a shift of a supply curve. (3 marks)

A full-mark answer covers all three components:

Movement along the supply curve is caused by a change in the good's own price. For example, if the price of wheat rises from £180 to £220 per tonne, farmers produce more wheat, and the point moves up and to the right along the same curve (an extension).
Shift of the supply curve is caused by a change in any non-price factor. For example, the government introduces a £30-per-tonne subsidy for wheat farmers; the supply curve shifts to the right at every price.
Distinct examples (one for each), as above.