Unit 5 Test: Factor Markets

How Labor and Resource Markets Work in AP Microeconomics

Unit 5 turns the analytical lens from product markets to factor markets — the markets where firms hire labor, capital, and land. The labor market is the primary focus of AP Microeconomics Unit 5, and FRQs in this unit require both numerical MRP calculations and accurate labor market diagrams.

Key Topics in Unit 5

Derived Demand for Labor

Firms do not hire labor for its own sake — they hire it because of the output it produces and the revenue that output generates. Demand for labor is therefore derived from the demand for the product. When product demand increases, labor demand increases as well. This concept is foundational to understanding why wages in different industries vary.

Marginal Revenue Product (MRP)

MRP is the additional revenue a firm earns from hiring one more unit of labor. It is calculated as:

MRP = Marginal Product of Labor (MPL) x Marginal Revenue (MR)

For a perfectly competitive firm in the product market, MR equals price, so MRP = MPL x P. A profit-maximizing firm hires workers up to the point where MRP equals the wage rate (MRP = W). AP questions provide tables of output at different labor levels and ask students to calculate MRP and identify the optimal number of workers to hire.

Competitive Labor Market

In a competitive labor market, the wage rate is determined by the intersection of labor supply and labor demand. Individual firms are wage takers — they face a horizontal supply of labor at the market wage. The labor demand curve is the MRP curve. Equilibrium occurs where labor supply equals labor demand.

Monopsony

A monopsony is a market with a single buyer of labor (or another input). Because the monopsonist faces an upward-sloping labor supply curve, hiring an additional worker requires paying a higher wage to all workers, so the marginal factor cost (MFC) curve lies above the supply curve. The monopsonist hires where MRP = MFC, resulting in fewer workers hired and a lower wage than in a competitive market. AP questions ask students to draw and compare monopsony and competitive outcomes.

Minimum Wage Effects

In a competitive labor market, a minimum wage set above equilibrium creates a surplus of labor (unemployment). In a monopsony, a minimum wage set at the competitive equilibrium level can actually increase both employment and wages simultaneously — a notable exception to the standard surplus analysis.

AP FRQ Skills for Unit 5

1. Calculate MRP from a table of labor inputs and outputs for a given product price.
2. Identify the profit-maximizing quantity of labor where MRP equals the wage.
3. Draw a correctly labeled labor market diagram showing supply, demand (MRP), equilibrium wage, and employment level.
4. Draw a monopsony diagram with MFC above labor supply and compare the outcome to a competitive equilibrium.