1. Demand in the Factor Market
Chapter 26
McGraw-Hill/Irwin
Copyright © 2011 by The McGraw-Hill Companies, Inc. All rights reserved.

2. Learning Objectives After this chapter, you should be able to:
Define and analyze derived demand.
Define and measure productivity.
Discuss and measure marginal revenue product.
Discuss changes in resource demand and list the four reasons for these changes.
Differentiate between the substitution effect and output effect.
Explain and analyze the optimum resource mix for the firm.

3. Derived Demand Derived demand is the demand for resources.
There are 4 resources: land, labor, capital, and entrepreneurial ability.
The demand for these resources is derived from the demand for the final products.
The demand for land on which to grow corn is derived from the demand for corn.
The demand for labor with which to produce cars is derived from the demand for cars.

4. Productivity Productivity is output per unit of input.
Productivity is measured by what is produced.
Inputs measure the 4 economic resources.
The more productive a resource is, the more it will be in demand.
This is reflected in both their prices and their rents.
Sally can get higher wages than John because she is more productive.
An acre of land that produces more cotton than another acre of land will command a higher rent.

5. Prices of Substitute Resources
A given good or service can usually be produced in many different ways.
Every country/organization uses the cheapest production method.
When wages rise, many companies seek to substitute machinery for relatively expensive human labor.
If land becomes more expensive, farmers work each acre more intensively, substituting labor and capital for more expensive land.
The demand for a resource is its marginal revenue product schedule (MRP).

6. Marginal Revenue Product (MRP)
MRP: the additional revenue obtained by selling the output produced by one more unit of a resource (e.g. labor).
How much of a resource is purchased depends on three things:
The price of that resource.
The productivity of that resource.
The selling price of the final product that the resource helps to produce.

7. Hypothetical Output of Labor Hired by a Firm
Fill in MPP
Note: MPP is identical to computing marginal output in diminishing returns, or change in output/change in units of input (L).

8. Hypothetical Output of Labor Hired by a Firm
Note: No business firm would hire more than 7 workers under these circumstances, even if the wage rate were a penny an hour.

9. Adding MRP into the Table
Total Revenue Product (TRP) = P x Q
Again, MRP is the additional revenue obtained by selling the output produced by one more unit of input.
= change in (TRP)/change in units of input.

10. Hypothetical Marginal Revenue Product Schedule (Perfect Competitor)
Fill in the columns. Hint: Use the TRP column to calculate MRP
because this method works for both perfect competition
and imperfect competition.

11. Hypothetical Marginal Revenue Product Schedule (Perfect Competitor)
How many units of land would you hire if you needed to pay $150
rent per unit?
If rent were $150, 3 units.

12. Hypothetical Marginal Revenue Product Schedule (Perfect Competitor)
How many units of land would you hire if you needed to pay $90 rent per unit?
Answer: 4 because the 5th unit is only worth $80.

13. The MRP Curve The MRP curve slopes down, just like any demand curve.
Units of labor

14. Hypothetical MRP Schedule of the Imperfect Competitor
Fill in the columns. Hint: Use the TRP column to calculate MRP
because this method works for both perfect competition
and imperfect competition.

15. Hypothetical MRP Schedule of the Imperfect Competitor
How many workers would be hired at a rate of $150? How much would the total wage bill be?
At $150, 2 workers would be hired.
The wage bill is (2 x $150) = $300.

16. The Marginal Revenue Product Curve of the Perfect and Imperfect Competitors
MRP
The MRP curve of the imperfect competitor declines more steeply than that of the perfect competitor because the imperfect competitor must lower price to sell additional output.
MRP in PC
MRP in
Imp. Comp.
Units of labor

17. Changes in Resource Demand
The MRP schedule (curve) is the firm’s demand schedule for a resource.
A change in the price of a resource (e.g. labor) affects the change in quantity demanded of that resource.
But other changes can shift the entire demand curve for the resource.
Upward to the right
Downward to the left

18. The Four Reasons for Changes in Resource Demand
Changes in demand for the final product
Most important reason
Productivity changes
Changes in the prices of other resources
Substitute factors
Substitution effect: if the price of a resource goes up, other resources will be substituted for it (and vice-versa).
Output effect: if a price of a resource rises, output of the final product declines, thus lowering employment of all resources (and vice-versa).
These two effects are contradictory; sometimes one is stronger than the other.
Complementary factors
Increase in use of one requires increase in use of the other.
Changes in the quantities of other resources

19. Optimum Resource Mix for the Firm
A firm will use increasing amounts of a resource until the MRP of that resource equals its price.
We would hire workers until the MRP of labor equals the price of labor
MRP of labor = Price of labor
MRP of labor Price of labor =
Price of labor Price of labor
MRP of labor
= 1
Price of labor

20. Optimum Resource Mix for the Firm
A firm will use increasing amounts of a resource until the MRP of that resource equals its price.
We would hire units of land until the MRP of land equals the price of land.
MRP of land = Price of land
MRP of land Price of land =
Price of land Price of land
MRP of land
= 1
Price of land

21. Optimum Resource Mix for the Firm
A firm will use increasing amounts of a resource until the MRP of that resource equals its price.
We would buy units of capital until the MRP of capital equals the price of capital
MRP of capital = Price of capital
MRP of capital Price of capital =
Price of capital Price of capital
MRP of capital
= 1
Price of capital

22. Questions for Thought and Discussion
Affordable household appliances made housework much easier and faster in the 1970s.
Result – instead of long hours on housework, many women went to work outside the home.
How can you explain this change in women’s roles using the concept of substitution effects?
Using the concept of output effects, explain how the decreased cost of household appliances might increase standards for cleanliness in the home.