Presentation on theme: "Interpreting Price Elasticity of Demand and other Elasticities"— Presentation transcript:
1 Interpreting Price Elasticity of Demand and other Elasticities
2 Clarifying Price Elasticities Perfectly inelasticWhen quantity demanded does not respond at all to changes in priceDemand curve is a vertical linePrice elasticity equals 0
3 Perfectly elasticWhen any price increase will cause the quantity demanded to drop to zero.Demand curve is horizontalThis implies an infinite price elasticity of demand
4 Elastic Inelastic Unit elastic Price elasticity of demand is greater than 1InelasticPrice elasticity of demand is less than 1Unit elasticPrice elasticity of demand is exactly 1
5 Why does it matter whether demand is elastic, inelastic or unit elastic? It helps predict how changes in price will affect total revenue, earned by producers from the sale of that good.Total Revenue = P X Q
6 Also two countervailing effects are present A price effectAfter a price increase, each unit sold sells at a higher price, which tends to raise revenueA quantity effectAfter a price increase, fewer units are sold, which tends to lower revenue
7 What factors determine Price Elasticity of Demand? Whether close substitutes are availablePrice elasticity of demand tends to be high if there are other goods that consumers regard as similar and would be willing to consume insteadPrice elasticity of demand tends to be low if there are no close substitutes
8 Whether a good is a necessity or a luxury? Price elasticity tends to be low if it is something you must havePrice elasticity tends to be high if the good is a luxury
9 Share of income spent on the good Price elasticity of demand tends to be low when spending on a good accounts for a small share of a consumer’s incomeA significant change in price has little impact on how much a consumer spendsWhen the good accounts for a significant share of consumer spending, consumer is less likely to be responsive to a change in price thus price elasticity of demand is high
10 TimePrice elasticity of demand tends to increase as consumers have more time to adjust to a price changeLong-run price elasticity of demand is higher than short-run elasticity.
11 Other Elasticities Cross-Price Elasticity of Demand Demand for a good is often affected by the prices on other goods (substitutes and complements)A change in the price of related good shifts the demand curve of the original good, reflecting a change in the quantity demanded at any given price.
12 This can be measured by the cross-price elasticity of demand It is a ratio of the percent change in the quantity demanded of one good to the percent change in the price of another.
13 If two goods are substitutes (i. e If two goods are substitutes (i.e. hot dogs/ hamburgers) cross-price elasticity of demand is positiveIf they are close substitutes cross-price elasticity will be positive and largeIf not cross-price elasticity will be positive and small
14 When two goods are complements (i. e When two goods are complements (i.e. hot dogs/ hot dog buns) cross-price elasticity is negativeIf the cross-price elasticity is slightly below zero, they are weak complements, if it is very negative, they are strong complementsIn the case of cross price elasticity the plus or minus sign is very important: it indicates whether the goods are substitutes or complements
15 Income Elasticity of Demand Measures how changes in income affect the demand for a goodIncome elasticity of demand can be both positive and negativeWhen the income elasticity of demand is positive, the good is a normal good- the quantity demanded at any given price increases as income increasesWhen it is negative, the good is an inferior good- quantity demanded at any given price decreases as income increases
16 Economist use income-elasticity of demand to predict which industries will grow most rapidly as incomes of consumers grow over time.This helps make a useful distinctions among normal goods
17 Income elasticThe income elasticity of demand for that good is greater than 1When income rises, the demand for income-elastic goods rise faster than incomeExample: second homes and international travel
18 Income inelasticThe income elasticity of demand for that good is positive but less than 1When income rises, demand for income-inelastic goods rises, but more slowly than incomeExample: food and clothing
19 Price Elasticity of Supply Definition: A measure of the responsiveness of the quantity of a good supplied to the price of that good. It is the ratio of the percent change in quantity supplied to the percent change in the price as we move along the supply curve.Formula
21 Factors that determine Price Elasticity of Supply Availability of InputsPrice elasticity of supply tends to be large when inputs are readily available and can be shifted into and out of production at a relatively low costPrice elasticity of supply tends to be small when inputs are available only in a more-or-less fixed quantity or can be shifted into and out of production only at a relatively high cost
22 TimePrice elasticity of supply tends to grow larger as producers have more time to respond to a price changeLong-run price elasticity of supply is often higher than short run elasticity
23 Short run = a few weeks or months Long run = several years