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Lesson M03.L03: Labour Market Equilibrium and the Wage Rate

Module: Unemployment and the Labour Market; Introduction to Short-Term Fluctuations Level: intro Duration: 30 minutes Learning Objective: Model labour market supply and demand; explain wage flexibility and market-clearing; illustrate equilibrium unemployment using a supply-demand diagram. Data as of: 2024 Provenance: OpenStax Macro 3e | fairwork.gov.au

Explanation

The labour market can be modelled like any other market, with a demand for labour (by firms) and a supply of labour (by workers), interacting to determine both the equilibrium wage rate and the equilibrium quantity of employment.

Labour demand slopes downward: as wages rise, labour becomes more costly and firms hire fewer workers. Conversely, lower wages encourage firms to hire more. The demand curve shifts when productivity changes, when product prices change, or when capital is substituted for labour.

Labour supply slopes upward: higher wages attract more people into the labour force and induce existing workers to offer more hours. The supply curve shifts with population changes, migration, changes in non-wage income, or shifts in preferences for work vs leisure.

Equilibrium occurs where supply equals demand. At equilibrium wage W and quantity Q, the market "clears" — every worker willing to work at W finds a job, and every firm willing to pay W finds a worker.

Unemployment in equilibrium: Even at the market-clearing wage, there may be workers who want jobs at a lower wage who cannot find them, and some who leave the market voluntarily. This gives rise to frictional and structural unemployment — the natural rate.

Wage rigidity introduces complications: minimum wages (Australia's National Minimum Wage was $24.10/hour from 1 July 2024), enterprise bargaining agreements, and efficiency wages can hold wages above the market-clearing level, producing a surplus of labour (unemployment). This is illustrated by the gap between quantity supplied and quantity demanded at a wage above W*.

Worked Example

Consider a simplified labour market for hospitality workers in Melbourne.

Given: - Labour demand: Q_D = 500,000 − 10,000W (where W = hourly wage in AUD, Q = number of workers) - Labour supply: Q_S = −100,000 + 20,000W

Step 1 — Find equilibrium wage (set Q_D = Q_S): 500,000 − 10,000W = −100,000 + 20,000W 600,000 = 30,000W W = 600,000 ÷ 30,000 = $20.00/hour*

Step 2 — Find equilibrium quantity: Q = 500,000 − 10,000(20) = 500,000 − 200,000 = 300,000 workers*

Step 3 — Introduce a minimum wage of $24.10/hour: Q_D at $24.10 = 500,000 − 10,000(24.10) = 500,000 − 241,000 = 259,000 workers demanded Q_S at $24.10 = −100,000 + 20,000(24.10) = −100,000 + 482,000 = 382,000 workers supplied

Step 4 — Calculate the labour surplus (unemployment): Surplus = Q_S − Q_D = 382,000 − 259,000 = 123,000 workers unemployed due to the wage floor

This simplified model shows how a binding minimum wage above equilibrium creates unemployment in the basic supply-demand framework — though in practice, minimum wage effects depend on market power, worker productivity, and demand elasticity.

Common Misconception

Misconception: A higher minimum wage always increases unemployment proportionally.

Correction: The basic competitive model predicts unemployment from a wage floor above equilibrium, but real labour markets are often not perfectly competitive. When employers have monopsony power (they are dominant buyers of labour), a minimum wage increase can actually increase employment up to a point, because it counteracts the employer's ability to suppress wages. Empirical research on Australia's minimum wage increases has generally found modest employment effects, not large layoffs. The model is a useful starting point, but real markets are more complex.

Practice Prompts

  1. Labour demand is Q_D = 400,000 − 8,000W and labour supply is Q_S = −50,000 + 12,000W. What is the equilibrium wage and quantity of employment? → Answer: Set equal: 400,000 − 8,000W = −50,000 + 12,000W → 450,000 = 20,000W → W = $22.50/hour. Q = 400,000 − 8,000(22.50) = 400,000 − 180,000 = 220,000 workers.

  2. Using the same functions as in Question 1, a minimum wage of $25/hour is introduced. How many workers are unemployed due to the wage floor? → Answer: Q_D = 400,000 − 8,000(25) = 200,000. Q_S = −50,000 + 12,000(25) = 250,000. Surplus = 250,000 − 200,000 = 50,000 workers.

  3. What would cause the labour demand curve to shift to the right (increase in demand for labour)? → Answer: Any of: an increase in the price of the final product workers produce; an increase in worker productivity; a decrease in the price of complementary inputs; economic expansion increasing firms' output targets. In Australia, a mining boom increases demand for mining labour, shifting the demand curve right and raising both wages and employment.

Visual — Labour Market Equilibrium and a Binding Minimum Wage

A binding minimum wage creates a labour surplus Labour employed / hours (Q) Real wage (W) Supply of labour Demand for labour W_min W* Q* Q_D Q_S Labour surplus (unemployment)

Figure: At the market equilibrium wage W, labour supply equals labour demand at Q. If a minimum wage is set above equilibrium, firms hire only Q_D while workers want to supply Q_S, creating a labour surplus (unemployment).

Further Resources