# Microeconomics

> IB Economics Higher Level · IB Economics HL
> Source: https://www.owlsprep.com/study/ib-economics-hl-u2-overview/
> Weight: 25-30% of overall IB Economics HL exam

This foundational unit explores the behavior of individual consumers, firms, and markets, forming the basis for all higher-level economic analysis. It covers core price theory, government intervention, market failure, and firm behavior across market structures.

**Prerequisites:** [Unit 1: Introduction to IB Economics](https://www.owlsprep.com/study/ib-economics-hl-u1-overview/)

## Learning objectives

- Explain how individual consumer and firm behavior interact to determine prices and output in different market types
- Evaluate the impact of government intervention on market welfare and outcomes
- Analyze firm behavior and efficiency under different market structures including imperfect competition
- Identify sources of market failure and evaluate the effectiveness of different policy remedies

## Unit at a Glance

This unit follows a logical learning progression, starting from core foundational concepts and building up to advanced HL-only topics. The first half covers the fundamentals of demand, supply, and market equilibrium, before moving into welfare analysis, government intervention, and market failure.

The second half of the unit focuses on the theory of the firm, analyzing how firms operate and perform under different market structures from perfect competition to oligopoly. HL-only extensions add game theory for interdependent firms and advanced quantitative analysis for exam preparation.

All sub-topics in this unit are listed below, in order of learning:
- [Demand theory](https://www.owlsprep.com/study/ib-economics-hl-u2-demand-theory/) — Covers the law of demand, determinants of demand, and the difference between movements along and shifts of the demand curve.
- [Supply theory](https://www.owlsprep.com/study/ib-economics-hl-u2-supply-theory/) — Explains the law of supply, key non-price determinants, and how to distinguish between movements and shifts.
- [Competitive market equilibrium](https://www.owlsprep.com/study/ib-economics-hl-u2-competitive-market-equilibrium/) — Explores how demand and supply interact to set market-clearing prices and adjust to external shocks.
- [Consumer and producer surplus](https://www.owlsprep.com/study/ib-economics-hl-u2-consumer-and-producer-surplus/) — Introduces welfare analysis to measure how gains from trade are distributed between consumers and producers.
- [Government intervention in markets](https://www.owlsprep.com/study/ib-economics-hl-u2-government-intervention-in-markets/) — Analyzes the impact of price controls, taxes, subsidies, and quotas on equilibrium and social welfare.
- [Overview of market failure](https://www.owlsprep.com/study/ib-economics-hl-u2-overview-of-market-failure/) — Introduces why unregulated free markets may fail to achieve socially efficient outcomes.
- [Types and remedies of market failure](https://www.owlsprep.com/study/ib-economics-hl-u2-types-and-remedies-of-market/) — Covers key categories of market failure and evaluates policy options to correct inefficient outcomes.
- [Theory of the firm and production costs](https://www.owlsprep.com/study/ib-economics-hl-u2-theory-of-the-firm-and/) — Explores production theory, cost classification, and the relationship between short-run and long-run costs.
- [Perfect competition](https://www.owlsprep.com/study/ib-economics-hl-u2-perfect-competition/) — Analyzes firm behavior, equilibrium, and efficiency outcomes in perfectly competitive markets.
- [Monopoly](https://www.owlsprep.com/study/ib-economics-hl-u2-monopoly/) — Covers monopoly power, pricing behavior, efficiency comparisons, and policy responses to monopolies.
- [Monopolistic competition and oligopoly](https://www.owlsprep.com/study/ib-economics-hl-u2-monopolistic-competition-and-oligopoly/) — Explores characteristics, equilibrium, and efficiency of two key imperfectly competitive market structures.
- [Price discrimination](https://www.owlsprep.com/study/ib-economics-hl-u2-price-discrimination/) — Explains conditions for and welfare impacts of different types of price discrimination by firms.
- [Game theory for oligopoly (HL only)](https://www.owlsprep.com/study/ib-economics-hl-u2-game-theory-for-oligopoly/) — Covers core game theory concepts to analyze interdependent decision-making by oligopoly firms (HL only).
- [Microeconomics quantitative analysis (HL only)](https://www.owlsprep.com/study/ib-economics-hl-u2-microeconomics-quantitative-analysis/) — Builds HL-specific quantitative skills for calculating elasticities, costs, and profit for exam assessment.

## Common pitfalls

- **Wrong:** Confusing movements along a curve vs shifts of the entire demand/supply curve
  - Why it fails: This common early error leads to incorrect predictions of how market equilibrium changes after external shocks
  - Correct: Always check: price changes cause movements along the curve, non-price determinants cause full shifts of the curve
- **Wrong:** Assuming all government intervention is always inefficient
  - Why it fails: While intervention can create deadweight loss in perfectly competitive markets, it can improve welfare when market failure exists
  - Correct: Evaluate intervention against the actual unregulated market outcome, not an idealized perfectly efficient baseline
- **Wrong:** Mixing up short-run and long-run firm equilibrium conditions
  - Why it fails: Firm entry/exit is only possible in the long run, so equilibrium outcomes differ significantly between time frames
  - Correct: Always explicitly state the time frame you are using when analyzing firm profit and market equilibrium

## Cheatsheet

| Concept | Key Formula / Rule |
| --- | --- |
| Price Elasticity of Demand | $PED = \frac{\% \Delta Q_d}{\% \Delta P}$ |
| Total Cost | $TC = TFC + TVC$ |
| Economic Profit | $\pi = TR - TC = (P - ATC) \times Q$ |
| Profit Maximization Rule | All firms maximize profit where $MR = MC$ |
| Individual Consumer Surplus | $CS = Willingness\ to\ Pay - Market\ Price$ |
| Total Social Surplus | $TS = CS + PS$ |
| Marginal Cost | $MC = \frac{\Delta TC}{\Delta Q}$ |
| Price Elasticity of Supply | $PES = \frac{\% \Delta Q_s}{\% \Delta P}$ |

## What's next

Start your learning of this unit with the first sub-topic below on demand theory, the foundational building block of all microeconomics. Progress through the sub-topics in order to build your understanding step-by-step from core concepts to advanced HL topics. Once you complete all topics in this unit, you will move on to the first sub-topic of the next unit on macroeconomics.

- [Demand theory](https://www.owlsprep.com/study/ib-economics-hl-u2-demand-theory/)
- [Supply Theory](https://www.owlsprep.com/study/ib-economics-hl-u2-supply-theory/)
- [Competitive market equilibrium](https://www.owlsprep.com/study/ib-economics-hl-u2-competitive-market-equilibrium/)

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