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M04.L02 — Shifts in Supply: Determinants and Comparative Statics

Module: Module 04 — Supply and Market Equilibrium Lesson: L02 of 06 Duration: ~30 minutes Level: Introductory Provenance: OpenStax Principles of Microeconomics 3e | Microeconomics 1e (Medeiros)

Learning Objective

Identify the five key determinants that shift the supply curve

Supply Shifters

While price changes cause movement along the supply curve, these five factors cause the entire curve to shift:

  1. Input prices: Rising costs of production decrease supply. Australian beef supply decreased when drought raised feed costs.
  2. Technology: Improvements increase supply. Automated mining equipment boosted Australian mineral exports.
  3. Expectations: Future price expectations affect current supply. Anticipating higher wool prices, farmers may withhold current supply.
  4. Number of sellers: More producers increase market supply. Entry of craft breweries expanded Australia's beer supply.
  5. Prices of related goods: If farmers can switch crops, higher prices for alternative crops may reduce supply of the original.

Worked Example

Australian Coal Supply Shift

  1. Baseline: Supply curve S1 at 100 million tonnes/year
  2. New carbon tax increases production costs → supply decreases to S2 (80 million tonnes)
  3. Simultaneously, new mining technology is adopted → supply increases to S3 (90 million tonnes)
  4. Net effect: Supply shifts left from S1 to S3 (10% decrease)

Common Misconception

"Bad weather always reduces supply"

While droughts reduce agricultural supply, ideal weather can increase it. The direction depends on the specific conditions.

Key Takeaways

  • Supply shifts require changing the entire supply schedule
  • Input costs and technology are most impactful in the long run
  • Multiple shifts can occur simultaneously
  • Australian examples demonstrate real-world applications

Practice

  1. How would a decrease in steel prices affect Australian car production?
  2. Why might avocado supply increase despite lower prices?
  3. Explain how mining technology affects Australia's comparative advantage

Further Resources

Provenance: OpenStax Principles of Microeconomics 3e | Microeconomics 1e (Medeiros)