Introduction to Factor Markets
Defines factors of production (labor, capital, land), their factor prices (wages, interest, rent), derived demand, and the core MRP = MRC hiring rule with calculation practice.
AP Microeconomics Unit 5 Review: Factor Markets
- 10–13% of AP multiple choice
- 4 topics
- AP exam review verified for 2027
A firm maximizes profit by hiring additional units of a factor as long as the marginal revenue product (MRP) exceeds the marginal resource cost (MRC), and stops exactly where MRP equals MRC. In a competitive labor market the wage equals MRC; in a monopsony the MRC curve lies above the labor supply curve, so the firm hires fewer workers and pays a lower wage than a competitive market would produce.
Fiveable's AP Microeconomics Unit 5 review covers 4 topics, with guided practice questions for the unit.
AP Microeconomics unit 5 topics
Changes in Factor Demand and Factor Supply
Covers what shifts the labor demand curve (output price, productivity) and the labor supply curve (immigration, education, working conditions, leisure preferences), and how to predict new equilibrium wages and employment.
Profit-Maximizing Behavior in Perfectly Competitive Factor Markets
Explains the two-panel competitive labor market graph, the wage-taker firm, the MRP = wage hiring rule, the VMP concept, and the cost-minimization rule MPL/w = MPK/r.
Monopsonistic Markets
Covers the monopsony graph with upward-sloping labor supply, MFC above supply, the MRP = MFC hiring rule, the lower wage outcome, deadweight loss, and the unique effect of a minimum wage in monopsony.
Practice AP Microeconomics unit 5 questions
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Unit 5 review notes
5.1
Introduction to Factor Markets
Factor markets are where firms (buyers) purchase inputs from households (sellers). The three main factors are labor, capital, and land, which earn wages, interest, and rent respectively. Demand for any factor is a derived demand because it depends on the demand for the final good the factor helps produce. Firms compare marginal revenue product to marginal resource cost to decide how many units of a factor to hire.
- Marginal Revenue Product (MRP): The additional revenue a firm earns from hiring one more unit of a factor. MRP = MPL x MR. In a competitive output market, MRP = MPL x Price.
- Marginal Resource Cost (MRC): The additional cost of hiring one more unit of a factor. In a competitive factor market, MRC equals the market wage.
- Profit-maximizing hiring rule: Hire additional units of a factor as long as MRP is greater than MRC; stop where MRP = MRC.
- Derived demand: Labor demand is derived from product demand. If the price of the output rises, the MRP of labor rises and the firm demands more labor at every wage.
- Diminishing marginal returns: As more labor is added with capital fixed, MPL eventually falls, causing MRP to fall. This gives the labor demand curve its downward slope.
Given a table showing output at each quantity of labor, calculate MPL, then MRP at a given output price, and identify the profit-maximizing number of workers at a stated wage.
| Factor | Factor Price | Market |
|---|---|---|
| Labor | Wage | Labor market |
| Capital | Interest rate | Capital market |
| Land | Rent | Land market |
5.2
Shifts in Factor Demand and Factor Supply
The labor demand curve shifts when the determinants of MRP change. The labor supply curve shifts when workers' willingness to supply labor at each wage changes. Understanding what shifts each curve and in which direction is essential for analyzing changes in equilibrium wages and employment.
- Labor demand shifters: Output price changes, changes in worker productivity, and changes in the price of related inputs (substitutes or complements in production) all shift the labor demand curve.
- Labor supply shifters: Immigration, changes in education levels, working conditions, age distribution of the population, availability of alternative jobs, preferences for leisure, and cultural expectations all shift labor supply.
- Movement along vs. shift: A change in the wage causes a movement along the labor demand or supply curve. A change in a determinant other than the wage causes the entire curve to shift.
- Productivity and labor demand: If workers become more productive (e.g., due to better technology or training), MPL rises, MRP rises at every quantity, and the labor demand curve shifts right.
- Immigration and labor supply: An increase in immigration expands the pool of available workers, shifting labor supply right, which lowers the equilibrium wage and increases equilibrium employment.
Identify whether a given event (e.g., a rise in the price of the output good, an influx of immigrant workers) shifts labor demand or labor supply, and predict the direction of the shift and the effect on equilibrium wage and employment.
| Curve | Shifts Right When | Shifts Left When |
|---|---|---|
| Labor Demand | Output price rises or productivity increases | Output price falls or productivity decreases |
| Labor Supply | Immigration increases or preferences for leisure fall | Population ages or preferences for leisure rise |
5.3
Perfectly Competitive Factor Markets
In a perfectly competitive labor market, many firms compete to hire from many workers. The market wage is determined by the intersection of market labor supply and market labor demand. Each individual firm is a wage taker and faces a perfectly elastic (horizontal) labor supply curve at the market wage. The firm hires where MRP equals the wage, which also equals MRC in this market structure.
- Wage taker: A firm in a competitive labor market accepts the market wage as given and can hire any number of workers at that wage without affecting it.
- MRP = Wage (hiring rule): Because MRC equals the wage in a competitive factor market, the firm hires until MRP = wage. The MRP curve is the firm's labor demand curve.
- Value of Marginal Product (VMP): VMP = MPL x Price. In a competitive output market, VMP equals MRP. It measures the dollar value of the extra output produced by one more worker.
- Cost minimization rule: To minimize costs across multiple inputs, a firm allocates inputs so that MPL/w = MPK/r, meaning the last dollar spent on each input yields the same marginal product.
- Two-panel graph: The market panel shows the equilibrium wage where market labor supply meets market labor demand. The firm panel shows a horizontal MRC line at that wage and a downward-sloping MRP curve; the firm hires where they intersect.
Draw the two-panel competitive labor market graph. Label the market wage, the firm's MRC line, the MRP curve, and the profit-maximizing quantity of labor. Then calculate MRP from a table and confirm the hiring decision.
5.4
Monopsonistic Labor Markets
A monopsony is a labor market with a single employer. Because the firm is the only buyer of labor, it faces the entire upward-sloping market labor supply curve. To hire one more worker, it must raise the wage for all workers, making the marginal factor cost (MFC) greater than the wage at every quantity. The firm hires where MRP = MFC, then pays the wage read off the labor supply curve at that quantity, which is below the competitive wage.
- Monopsonist: A single employer in a labor market who has the power to set wages. Examples include a dominant employer in a small town or a specialized industry with few firms.
- MFC greater than wage: Because hiring one more worker requires raising wages for all existing workers, MFC exceeds the labor supply curve at every quantity of labor.
- Monopsony hiring rule: The firm hires where MRP = MFC, then pays the wage shown on the labor supply curve at that employment level, not the MFC value.
- Monopsony vs. competitive outcome: Compared to a competitive market, a monopsony hires fewer workers and pays a lower wage, creating deadweight loss.
- Minimum wage in monopsony: A minimum wage set between the monopsony wage and the competitive wage can increase both employment and wages in a monopsonistic market, unlike in a competitive market where a binding minimum wage reduces employment.
Given a monopsony graph with MRP, MFC, and labor supply curves labeled, identify the profit-maximizing quantity of labor, the wage the firm pays, and explain why MFC lies above the labor supply curve.
| Feature | Competitive Labor Market | Monopsony |
|---|---|---|
| Number of employers | Many | One |
| Firm's labor supply curve | Horizontal (perfectly elastic) | Upward sloping (market supply) |
| MRC vs. wage | MRC = wage | MFC > wage |
| Hiring rule | MRP = wage | MRP = MFC |
| Wage outcome | Competitive wage | Below competitive wage |
Key terms
| Term | Definition |
|---|---|
| Derived Demand | The demand for a factor of production that depends on the demand for the final good the factor helps produce. Labor demand rises when output price or worker productivity rises. |
| MFC equals MRP | The profit-maximizing hiring condition. A firm hires additional labor as long as MRP exceeds MFC and stops where they are equal. |
| Factors of Production | The inputs used to produce goods and services: labor, capital, and land. Each earns a factor price: wages, interest, and rent respectively. |
| Labor Demand | The quantity of labor firms are willing to hire at each wage rate. It slopes downward because MRP falls as more labor is hired. It shifts when output price or worker productivity changes. |
| Labor Supply | The quantity of labor workers are willing to offer at each wage rate. It slopes upward. It shifts due to immigration, education, working conditions, leisure preferences, and demographic changes. |
| wage rate | The price of labor per unit of time. In a competitive labor market, it is determined by market supply and demand and is taken as given by individual firms. |
| Marginal Product | The additional output produced by hiring one more unit of a factor, with all other inputs held constant. Diminishing marginal returns cause MPL to fall as more labor is added. |
| monopsonist | A single employer in a labor market who faces the entire upward-sloping labor supply curve and has the power to set wages below the competitive level. |
| monopsonistic labor market | A labor market with one dominant employer. The firm hires where MRP = MFC and pays the wage from the labor supply curve, resulting in lower employment and wages than a competitive market. |
| Demand Curve for Labor | A downward-sloping curve showing the quantity of labor firms demand at each wage. It is equivalent to the MRP curve for the firm. |
| Minimum wage | A legally set floor on wages. In a competitive labor market, a binding minimum wage above equilibrium reduces employment. In a monopsony, a minimum wage between the monopsony wage and the competitive wage can increase both wages and employment. |
How to review unit 5
Topics students miss most
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5.3
Profit-Maximizing Behavior in Perfectly Competitive Factor Markets
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Common unit 5 mistakes
Paying the MFC wage instead of the supply curve wage in monopsony
In a monopsony, the firm hires where MRP = MFC, but it pays the wage shown on the labor supply curve at that quantity, not the MFC value. The MFC point is only used to find how many workers to hire.
Confusing a shift in labor demand with a movement along it
A change in the wage causes a movement along the labor demand curve. Only changes in output price, worker productivity, or the price of related inputs shift the entire labor demand curve.
Using MR = Price for imperfect competitors in output markets
MRP = MPL x MR. For a firm that is a price taker in the output market, MR = Price, so MRP = MPL x Price = VMP. For a monopolist or oligopolist in the output market, MR is less than Price, so MRP is less than VMP.
Assuming a minimum wage always reduces employment
In a competitive labor market, a binding minimum wage above the equilibrium wage reduces employment. In a monopsony, a minimum wage set between the monopsony wage and the competitive wage can increase employment. The market structure determines the outcome.
Forgetting that a firm can be a wage taker in the labor market even if it has output market power
A monopolist in its product market can still be a perfectly competitive buyer of labor if there are many employers competing for workers. Market structure in the output market and the factor market are determined separately.
How this unit shows up on the AP exam
Graph drawing and labeling
AP Micro frequently asks students to draw and fully label factor market graphs. For competitive labor markets, you need both the market panel (equilibrium wage) and the firm panel (horizontal MRC, downward-sloping MRP, and the hiring quantity). For monopsony, you need the upward-sloping labor supply, the MFC curve above it, the MRP curve, and the two-step process to find quantity and wage. Incomplete labels or missing curves cost points.
Calculation from tables
Exam questions often provide a table of labor quantities and total output, then ask you to calculate MPL, MRP at a given output price, and the profit-maximizing number of workers at a stated wage. You may also be asked to apply the cost-minimization rule MPL/w = MPK/r to determine whether a firm should shift spending between inputs.
Comparative analysis across market structures
Questions may ask you to compare outcomes in competitive versus monopsonistic labor markets, including differences in wage, employment level, and efficiency. The effect of a minimum wage is a common comparison task because the direction of the employment effect depends entirely on whether the market is competitive or monopsonistic.
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get printablesFrequently Asked Questions
What's on the AP Micro Unit 5 progress check (MCQ and FRQ)?
The AP Micro Unit 5 progress check includes both MCQ and FRQ parts that test all four factor market topics. The MCQ section covers concepts like marginal revenue product, marginal resource cost, shifts in factor demand and supply, and monopsony wage and employment outcomes. The FRQ part typically asks you to draw and interpret factor market graphs, identify profit-maximizing hiring rules, and analyze the effects of a monopsonist compared to a competitive market. Practice questions matched to this progress check are at /ap-micro/unit-5.
How do I practice AP Micro Unit 5 FRQs?
AP Micro Unit 5 FRQs most often come from Topics 5.3 and 5.4, asking you to draw a perfectly competitive factor market or a monopsony graph, label the profit-maximizing quantity of labor, and compare wages under different market structures. To practice, sketch the MRP and MRC curves from memory, then work through questions that ask you to show the effect of a change in product price or a shift in labor supply. Check /ap-micro/unit-5 for FRQ practice sets tied to these topics.
Where can I find AP Micro Unit 5 practice questions?
The best place to find AP Micro Unit 5 practice questions, including multiple-choice and practice test sets, is /ap-micro/unit-5. There you'll find MCQs covering factor demand shifts, marginal revenue product calculations, and monopsony outcomes, plus FRQ practice that mirrors the format of the actual exam. Targeting questions by topic (5.1 through 5.4) helps you pinpoint which factor market concepts still need work.
How should I study AP Micro Unit 5?
Start by building a clear understanding of how factor markets work: firms hire up to the point where marginal revenue product equals marginal resource cost. From there, work through each topic in order. For 5.1 and 5.2, practice drawing factor demand and supply graphs and listing what causes each curve to shift. For 5.3, drill the MRP = MRC hiring rule until it's automatic. For 5.4, compare monopsony outcomes (lower wages, fewer workers hired) to competitive markets on the same graph. Finish each study session with a few MCQs or a short FRQ to check your graph-drawing accuracy. Find topic-by-topic resources at /ap-micro/unit-5.