Labour-market equilibrium, wage differences and rent
Labour-market equilibrium, wage differences and rent: build the core model, apply it to evidence and qualify conclusions where outcomes depend on context.
9708 section 8.3; A Level. Checked against Cambridge's 2026–2028 Version 2 (latest version published December 2025) and 2029 Version 1 (published September 2026). Cambridge states that neither version has significant changes affecting teaching. Always follow the syllabus for the candidate's examination year.
Before you begin
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is economic rent?
What you will learn
- Explain movements along and shifts in labour supply
- Analyse wage determination in perfect labour markets
- Evaluate unions, minimum wages and monopsony
- Explain wage differentials
- Distinguish transfer earnings from economic rent
Core model and terms
In a competitive labour market, the intersection of labour demand and supply determines an equilibrium wage and employment. A wage change causes movement along supply; population, qualifications, migration, preferences, working conditions and occupational barriers can shift supply. Wage differences can reflect productivity, training, scarcity, risk, location, working conditions, bargaining power and discrimination; observed pay alone cannot identify which cause dominates.
Apply and evaluate
Trade unions may bargain collectively to raise wages and change employment, with effects depending on bargaining power and the firm’s demand for labour. A binding national minimum wage can raise pay for covered workers but may reduce labour demanded in a competitive model; monopsony power can instead hold wages below the competitive outcome, so a moderate floor can raise wages and employment. Transfer earnings are the minimum payment needed to keep a factor in its current use; economic rent is payment above that amount. Scarcity and alternative opportunities affect the split.
Pause and explain
Which statement best applies labour-market equilibrium, wage differences and rent?
Worked example
A specialist earns $50 per hour in a role and would accept $18 per hour to remain in that occupation. Calculate economic rent per hour and interpret it.
Show the worked solution
- Economic rent = $50 − $18 = $32 per hour
- $18 is the transfer-earnings threshold
- The remaining $32 is payment above what is needed to keep the specialist in this use
Answer Economic rent = $50 − $18 = $32 per hour → $18 is the transfer-earnings threshold → The remaining $32 is payment above what is needed to keep the specialist in this use
Try a topic test
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Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A specialist earns $50 per hour in a role and would accept $18 per hour to remain in that occupation. Calculate economic rent per hour and interpret it.
Give me a hint
Subtract the transfer earnings from the actual payment.
Compare my reasoning
- Economic rent = $50 − $18 = $32 per hour
- $18 is the transfer-earnings threshold
- The remaining $32 is payment above what is needed to keep the specialist in this use
Economic rent = $50 − $18 = $32 per hour $18 is the transfer-earnings threshold The remaining $32 is payment above what is needed to keep the specialist in this use
Look for these in your work
- Economic rent = $50 − $18 = $32 per hour
- $18 is the transfer-earnings threshold
- The remaining $32 is payment above what is needed to keep the specialist in this use
A labour market has wage above equilibrium after a binding minimum is set. In the competitive model, compare labour supplied with labour demanded.
Give me a hint
Use the movement along each curve caused by a higher wage.
Compare my reasoning
- At the higher wage more people are willing to supply labour
- Firms demand fewer workers
- A surplus of labour can result, though actual outcomes depend on coverage and market conditions
At the higher wage more people are willing to supply labour Firms demand fewer workers A surplus of labour can result, though actual outcomes depend on coverage and market conditions
Look for these in your work
- At the higher wage more people are willing to supply labour
- Firms demand fewer workers
- A surplus of labour can result, though actual outcomes depend on coverage and market conditions
A large employer faces an upward-sloping labour supply curve. Explain how monopsony power can affect wage and employment relative to competition.
Give me a hint
Compare the employer’s hiring choice with the wage-taking competitive benchmark.
Compare my reasoning
- The employer recognises that attracting more labour may require a higher wage
- Its marginal cost of labour can exceed the wage
- It may choose lower employment and pay than a competitive market
The employer recognises that attracting more labour may require a higher wage Its marginal cost of labour can exceed the wage It may choose lower employment and pay than a competitive market
Look for these in your work
- The employer recognises that attracting more labour may require a higher wage
- Its marginal cost of labour can exceed the wage
- It may choose lower employment and pay than a competitive market
Why may a union-negotiated wage rise change employment differently at a monopsony employer than in a perfectly competitive market?
Give me a hint
Compare the starting wage and hiring decision in the two market structures.
Compare my reasoning
- A competitive firm may reduce labour demanded when wage rises
- A monopsonist may initially pay below workers’ marginal revenue product
- Bargaining can raise wages and may also increase employment over some range
A competitive firm may reduce labour demanded when wage rises A monopsonist may initially pay below workers’ marginal revenue product Bargaining can raise wages and may also increase employment over some range
Look for these in your work
- A competitive firm may reduce labour demanded when wage rises
- A monopsonist may initially pay below workers’ marginal revenue product
- Bargaining can raise wages and may also increase employment over some range
Common mistakes
- Assuming every minimum wage reduces employment or that an observed wage difference proves a difference in worker productivity.
What can you explain now?
What is economic rent?
Compare with the explanation
Payment to a factor above its transfer earnings
It is the part of a payment exceeding the minimum needed to keep the factor in its current use.
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Make it stick
Before moving on, explain the central idea in labour-market equilibrium, wage differences and rent and state one condition that could change its effect.
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