Dissertation
Topic 3: Elasticities of Demand & Supply
Topic 3: Elasticities of Demand & Supply
Chapter 3 Elasticities of demand and supply
(Chapter 4 Begg et. al, Chapter 3, Turley et. al.) TOPIC 3
The price elasticity of demand
…measures the sensitivity of the quantity demanded of a good to a change in its price It is defined as: % change in quantity demanded % change in price
Sandra.kelly@itcarlow.ie
Sandra.kelly@itcarlow.ie
Economics Year 1
TOPIC 3 Page 1
Economics Year 1
Topic 3: Elasticities of Demand & Supply
Topic 3: Elasticities of Demand & Supply
The price elasticity of demand
FORMULA Price Elasticity (Point Method)
Q1 = Original quantity Q2 = New quantity P1 = Original price P2 = New price ΔQ = Change in Quantity ΔQ = Change in Price
Q2 - Q1 Q1 P2 - P1 P1 x 100 x 100 = ΔQ Q ΔP P x 100 x 100
Elastic demand
• Demand is ELASTIC – when the price elasticity is greater than -1
• (often the minus sign is ignored)
NB: YOU WILL NOT BE GIVEN THIS FORMULA IN THE EXAM
Sandra.kelly@itcarlow.ie
– i.e. when the % change in quantity demanded exceeds the % change in price • e.g. if quantity demanded falls by 7% in response to a 5% increase in price • elasticity is -7 ÷ 5 = -1.4
Sandra.kelly@itcarlow.ie
TOPIC 3 Page 2
Economics Year 1
TOPIC 3 Page 3
Economics Year 1
Topic 3: Elasticities of Demand & Supply
Topic 3: Elasticities of Demand & Supply
Inelastic demand
• Demand is INELASTIC – when the price elasticity lies between -1 and 0 – i when the % change in quantity i.e. h h h i i demanded is smaller than the % change in price • e.g. if quantity demanded falls by 3.5% in response to a 5% increase in price • elasticity is -3.5 ÷ 5 = - 0.7
Sandra.kelly@itcarlow.ie
Unit elastic demand
• Demand is UNIT ELASTIC – when the price elasticity is exactly -1 – i.e. when the % change in quantity g q y demanded is equal to the % change in price • e.g. if quantity demanded falls by 5% in response