1. Elasticity, Total Revenue and Surplus
Micro Chapter 18 Cont’d

2. Quick Check 1
Items that are necessities are considered to be _____________
inelastic

3. Quick Check 2
If TR and price go in opposite directions, the good is considered to be _______
Elastic

4. Quick Check 3 List the determinants of elasticity
P- the proportion of income spent on the good
A- availability of close substitutes (the more subs. The more elastic)
I- the importance of a good (luxury v necessity)
D- the ability to delay the purchase (the more time, the more elastic)

5. Quick Check 4
If a good has an elasticity coefficient of 0, that good is said to be ___________
Perfectly inelastic

6. Price Elasticity Elastic Ed > 1 Unit Elastic Ed = 1 Inelastic1 2 3 4 5 6 7 8
Quantity Demanded
Price $8
Elastic
Ed > 1 a b c d e f g h
Unit Elastic
Ed = 1
Inelastic
Ed < 1 D

7. Excise Taxes
Governments tend to tax inelastic products to ensure high revenues
Ex- liquor, gasoline and tobacco

8. Price Elasticity of Supply
If producers are relatively responsive to price changes, supply is elastic. If producers are relatively unresponsive to price change, supply is inelastic
Es = Percentage change in quant supplied of product x/percentage change in price of product x
Or….Es = change S/sum of S/2 / change P/sum P/2
Ex- Solve Es for an increase in price from $4-6 and increase in quantity supplied from 10 units to 14 units (use midpoint)

9. Check your work
Es = change quant supplied/(sum of Qs/2)/(change price/sum of P/2)
= ((14-10)/(14+10/2))/((6-4)/(6+4/2))
= (4/12)/(2/5)
= .33/.40
= .83

10. Price Elasticity of Supply Cont’d
The degree of price elasticity of supply depends on how easily and quickly producers can shift resources between alternative uses

11. Market Period
A period that occurs when the time immediately after a change in market price is too short for producers to respond with a change in quantity supplied

12. Market Period Continued
Ex- perishable items are perfectly inelastic such as beets. Farmers will sell all of their product because they will go bad
The market period for a farmer is the growing season

13. Short run
a period of time too short to change plant capacity but long enough to use fixed plant more or less intensively

14. Long Run
Time period long enough for firms to adjust plant sizes and for new firms to enter and old firms to leave an industry
Ex- in the tomato industry the farmer has time to acquire new land and buy machinery. Over time more farmers will shift to tomatoes if profitable