Cross Price Elasticity of Demand AS Economics

Cross Elasticity of Demand (CPed) Cross price elasticity (CPed) measures the responsiveness of demand for good X following a change in the price of good Y (a related good) CPeD = % change in qty D of product A % change in price of product B With cross price elasticity we make an important distinction between substitute products and complementary goods and services.

Identify some Substitutes

Identify some Complements

Cross Price Elasticity for Substitutes ProductClose Substitute Weak Substitute Good with no relationship Coca Cola Camembert Cheese Euro Star Journey from London to Paris Dowe Egberts Filter Coffee Ticket to a film at the UGC Cinema in Slough

Complementary Goods ProductClose Complement Weak Complement Good with no relationship Personal Computer A bottle of expensive white wine Short Break Weekend in Barcelona

Cross Elasticity of Demand (CPed) + = Substitutes Substitutes:  With substitute goods such as brands of razors, an increase in the price of one good will lead to an increase in demand for the rival product  Weak substitutes – inelastic CPed  Close substitutes – elastic CPed Cross price elasticity will be positive +

Cross Elasticity of Demand (CPed) - = Complements Complements:  Goods that are in complementary demand  Weak complements – inelastic CPed  Close complements –  elastic CPed The cross price elasticity of demand for two complements is negative

The Diagrams!

Substitutes Price of Good S Quantity demanded of Good T Demand Two Weak Substitutes P1 P2 Goods S and T are weak substitutes A rise in the price of Good S leads to a small rise in the demand for good T The cross price elasticity of demand will be positive but the coefficient of elasticity will be less than one Ice cream and lollies! +

Complements Price of Good X Quantity demanded of Good Y Deman d Two Close Complements P2 P1 Goods X and Y are close complements A fall in the price of good X leads to a large rise in the demand for good Y The cross price elasticity of demand will be negative and the coefficient of elasticity will be more than one Complements are said to be in JOINT DEMAND Foreign holidays & air flights! -

Goods with zero cross-price elasticity of demand aka. INDEPENDENT Price of Good A Quantity demanded of Good B Demand P1 P2 P3 Goods A and B have no relationship. A fall in the price of good A leads to no change in the demand for good B Therefore the cross-price elasticity of demand is zero Apples and gloves!

Get your calculators ready CPeD = % change in qty D of product A % change in price of product B

Calculate the CPeD and state whether the goods are complements or substitutes? 1.A 10% rise in the price of fish may cause demand for chicken to increase by 2%. 2.The fall in the price of paper by 20% causes the demand for pens to increase by 5%. 3.A 20% rise in the price of ice cream causes demand for sweets to increase by 4%. 4.A 12% fall in the price of air fares leads to a 30% rise in the demand for foreign holidays. 5.A 10% rise in bikes will leave the demand for cheese unaffected.

Answers… A 10% rise in the price of fish may cause demand for chicken to increase by 2%. +2/+10 = +0.2 The fall in the price of paper by 20% causes the demand for pens to increase by 5%. +5/-20 = A 20% rise in the price of ice cream causes demand for sweets to increase by 4%. +4/+20 = +0.2 A 12% fall in the price of air fares leads to a 30% rise in the demand for foreign holidays. +30/-12 = -2.5 A 10% rise in bikes will leave the demand for cheese unaffected. 0/+10 = 0 Positive = substitute goods Negative = complementary

Look at some figures for interpretation… Real statistics!

Estimated Elasticity for Alcohol How can beer be a good complement to beer? Positive = substitute goods Negative = complementary In your own words explain the ‘wine’ CPeD numbers

Importance of CPed for businesses Firms can use CPed estimates to predict: The impact of a rival’s pricing strategies on demand for their own products: Pricing strategies for complementary goods:  Popcorn and cinema tickets are strong complements. Popcorn has a very high mark up i.e. popcorn costs pennies to make but sells for more than a pound  If firms have a reliable estimate for XED they can estimate the effect, say, of a two-for-one cinema ticket offer on the demand for popcorn

Applications of Cross Elasticity (1) Effects of the national minimum wage on demand for younger and older workers (might younger workers be replaced?) Higher indirect taxes on goods such as tobacco – the impact on demand for nicotine patches and other substitutes

Applications of Cross Elasticity (2) Effect on demand for different modes of mass transport following introduction of road pricing schemes in urban areas (e.g. the London congestion charge and the M6 Toll Road) Rise in the price of natural gas – effect on the demand for coal used in power generation

Homework Revise for test next lesson – to review basic definitions, formulas, diagrams, elastic & inelastic numbers PeD YeD PeS CPeD