Definition of supply

Published by Patrick Mutisya · 14 days ago

Cambridge IGCSE Economics 0455 – The Allocation of Resources: Supply

The Allocation of Resources – Supply

Objective

Students will be able to state the definition of supply and understand the basic concepts that underlie it.

Definition of Supply

Supply is the quantity of a good or service that producers are willing and able to sell at different prices during a given period of time, ceteris paribus (all other factors remaining constant).

In mathematical terms, the supply function can be expressed as:

\$Q_s = f(P, \text{determinants})\$

where Qₛ is the quantity supplied, P is the market price, and the determinants include factors such as input prices, technology, and expectations.

Key Points

  • Supply relates to the producer’s side of the market.
  • The relationship between price and quantity supplied is generally positive – higher prices encourage producers to supply more.
  • The phrase “ceteris paribus” is essential; it isolates the effect of price by holding other influences constant.

Determinants of Supply

DeterminantEffect on Supply (ceteris paribus)
Input pricesHigher input costs → supply decreases; lower input costs → supply increases
TechnologyImproved technology → supply increases; outdated technology → supply decreases
Number of sellersMore sellers → supply increases; fewer sellers → supply decreases
Expectations of future priceExpect higher future price → current supply may decrease (producers hold back); expect lower future price → current supply may increase
Taxes and subsidiesHigher taxes → supply decreases; subsidies → supply increases
Government regulationsStringent regulations (e.g., quotas) → supply decreases; deregulation → supply increases

Supply Curve

The supply curve graphically represents the relationship between price and quantity supplied. It typically slopes upward from left to right, reflecting the direct relationship between price and quantity supplied.

Suggested diagram: Upward‑sloping supply curve showing price on the vertical axis and quantity supplied on the horizontal axis.

Summary

  1. Supply is the amount producers are willing and able to sell at various prices.
  2. The supply relationship is positive: higher prices usually lead to higher quantities supplied.
  3. Several determinants can shift the entire supply curve left (decrease) or right (increase).