Unit 1 — Markets in Action
1Introductory Concepts
1.1 What is Economics?
Economics is the study of how scarce resources are allocated among competing unlimited wants.
Factors of Production
| Factor | Definition | Payment |
|---|---|---|
| Land | Natural renewable/non-renewable raw resources | Rent |
| Labour | Human physical/mental work input | Wages |
| Capital | Fixed (machinery) + Working (materials) | Interest |
| Enterprise | Risk-taking organisers combining factors | Profit |
Economic goods: scarce, require resources, have opportunity cost.
Production Possibility Frontier (PPF)
Specialisation & Division of Labour
Specialisation: individuals/firms/nations focus on narrow production tasks. Division of labour: splitting production into separate repetitive tasks.
- Benefits: repetition raises productivity and skill; less time is lost switching tasks; specialist capital can be used.
- Costs: repetitive work can reduce motivation and quality; workers become less occupationally flexible; production becomes interdependent.
Money and Financial Markets
Money enables specialisation by avoiding barter. Its four functions are medium of exchange, measure of value, store of value, and method of deferred payment.
Financial markets channel savings to households and firms, support payments, provide forward markets for commodities and currencies, and provide a market for equities.
Economic Systems
| System | Decision-maker |
|---|---|
| Free market | Individuals / firms via price mechanism |
| Command (planned) | Government sets output, prices, distribution |
| Mixed economy | Both — most real-world economies |
1.2 Positive vs Normative
| Positive | Normative |
|---|---|
| Objective, testable, backed by data | Subjective, value-based judgement |
| “Inflation is 3%” | “Inflation is too high” |
Consumer Behaviour
- Rational decision making: consumers maximise total utility
- Law of diminishing marginal utility: extra unit consumed yields less extra satisfaction
- Consumer surplus: difference between max willingness to pay & actual market price
2Consumer Behaviour & Demand
2.1 The Law of Demand
Limits to Rational Decision-Making
Utility maximisation is an assumption, not a description of every choice. Decisions may be affected by herding, habits, inertia, weak computational skills, the need to feel valued, and framing or cognitive bias.
Movement along vs Shift
| Movement along | Shift of curve |
|---|---|
| Change in price | Change in non-price factors |
| Change in quantity demanded | Change in demand |
Non-price Determinants of Demand
- Income — normal good (up income, up demand); inferior good (up income, down demand)
- Prices of related goods — substitutes (XED > 0); complements (XED < 0)
- Tastes and fashion
- Expectations of future price changes
- Population
2.2 Price Elasticity of Demand (PED)
| PED Value | Meaning |
|---|---|
| |PED| > 1 | Elastic |
| |PED| = 1 | Unit elastic |
| |PED| < 1 | Inelastic |
| PED = 0 | Perfectly inelastic (vertical) |
| PED = ∞ | Perfectly elastic (horizontal) |
PED and Total Revenue
- Elastic (|PED| > 1): price up, total revenue down
- Inelastic (|PED| < 1): price up, total revenue up
Determinants of PED
- Substitutes — more available = more elastic
- Necessity vs luxury — necessities tend inelastic
- Proportion of income — larger share = more elastic
- Time period — longer = more elastic
2.3 Income Elasticity (YED)
- YED > 0 → normal good (necessity: 0 < YED < 1; luxury: YED > 1)
- YED < 0 → inferior good
2.4 Cross-Price Elasticity (XED)
- XED > 0 → substitutes
- XED < 0 → complements
- XED = 0 → unrelated
3Supply
3.1 The Law of Supply
A movement along S is caused only by a change in the good's own price. A shift of S is caused by a non-price determinant.
Non-price determinants (shift S)
- Input costs — wages, raw materials, energy, rent. Higher costs shift S left.
- Technology and productivity — lower unit cost, S right.
- Number of firms — entry shifts market S right.
- Indirect tax — vertical shift up by the tax; subsidy — shift down/right.
- Weather / shocks — especially agriculture and commodities.
- Price of related goods in production — if wheat pays more, land leaves barley (barley S left).
- Expectations — expected future price rise may withhold stock now (S left today).
3.2 Price Elasticity of Supply
- PES > 1 elastic; 0 < PES < 1 inelastic; PES = 0 perfectly inelastic (vertical); PES = ∞ perfectly elastic (horizontal).
- Use percentage changes, not raw units, and keep the sign convention used in the paper (PES is usually treated as positive).
Determinants of PES
- Time — momentary supply is often inelastic; long run more elastic as capacity can be built.
- Spare capacity and stocks raise PES.
- Factor mobility and simple production raise PES; long training or unique land lowers it.
- Perishability — fresh food cannot be stored, so short-run PES is low.
4Price Determination
4.1 Market Equilibrium
- Surplus (excess supply) above Pe: unsold stock, firms cut price toward Pe.
- Shortage (excess demand) below Pe: queues, firms raise price toward Pe.
4.2 Functions of the Price Mechanism
- Signalling — a rising price tells producers the good is scarcer or more valued.
- Incentive — higher price raises potential profit, so firms expand; consumers economise.
- Rationing — the scarce good goes to those willing and able to pay.
4.3 Shifts of Demand or Supply
Demand right (income, tastes, price of substitutes up, complements down) → Pe and Qe both rise. Supply right (lower costs, better technology, subsidy) → Pe falls and Qe rises. Always state the shift, the disequilibrium, then the new equilibrium. Combined shifts make one of Pe or Qe ambiguous unless you are told which curve moves more.
4.4 Consumer and Producer Surplus
Consumer surplus is the difference between what consumers are willing to pay and what they do pay (area under D above price). Producer surplus is the difference between price and the minimum producers would accept (area above S below price). A binding price ceiling cuts Q, creates a shortage and usually reduces total surplus (deadweight loss).
5Market Failure
5.1 Types of Market Failure
Complete market failure: market fails to exist entirely.
5.2 Externalities
| Type | Relationship | Example |
|---|---|---|
| Negative production | Social cost > Private cost | Factory pollution |
| Positive production | Social benefit > Private benefit | Beekeeper helps orchards |
| Negative consumption | Social cost > Private cost | Smoking, loud music |
| Positive consumption | Social benefit > Private benefit | Vaccination, education |
Merit and Demerit Goods
- Merit goods — under-consumed because individuals underestimate private benefits (education, healthcare)
- Demerit goods — over-consumed because individuals underestimate private costs (drugs, junk food)
5.3 Public Goods
5.4 Information Gaps
- Asymmetric information — one party holds more information
- Adverse selection — hidden information before a transaction attracts higher-risk participants and can drive lower-risk participants out
- Moral hazard — party takes greater risks after being insulated
- Principal-agent problem — agents act in own interest instead of principal’s
6Government Intervention
6.1 Indirect Tax
A tax on spending (e.g., VAT). Shifts supply left. The burden is shared between consumers and producers depending on elasticity.
6.2 Subsidies
A payment from government to producers. Shifts supply right, lowering price for consumers.
6.3 Price Controls
| Control | Effect |
|---|---|
| Price ceiling (max price) | Set below equilibrium — shortages, black markets |
| Price floor (min price) | Set above equilibrium — surplus, stockpiling costs |
6.4 Other Tools
- Regulation — legal controls on production/consumer activity
- Tradeable pollution permits — cap-and-trade for emissions
- State provision — government supplies public services directly
6.5 Government Failure
7Diagram, Data and Evaluation Toolkit
Choose the diagram from the economic mechanism
| If the question is about... | Usually draw... | Minimum annotation |
|---|---|---|
| A tax, subsidy, external cost/benefit or price control | Supply and demand, with MSC/MSB where relevant | Original and new equilibrium, price, quantity, welfare area or shortage/surplus. |
| Inflation, growth, unemployment or demand-side policy | AD-AS | AD/SRAS/LRAS shift, real output and price level; label the starting output gap if relevant. |
| Growth in productive potential | LRAS or PPF | Outward shift and the specific cause: investment, labour quality, technology or productivity. |
| Firm output, market structure or allocative efficiency | AR/MR/AC/MC cost-revenue diagram | MC = MR output, price from AR, and the relevant profit/loss or welfare implication. |
| Wages, minimum wage or labour shortages | Labour demand and supply | Wage, employment, and excess supply/demand of labour if intervention is imposed. |
| Currency movement or trade | Foreign-exchange demand and supply | Currency price, appreciation/depreciation direction, and the demand/supply shifter. |
Build an analytical chain, not a list
Name the change and the affected agents.
Explain the curve shift, incentive, cost or expectation.
State the effect on price, output, employment, welfare or distribution.
Use the extract's figure, country, industry or time period.
Qualify the outcome using a decisive condition.
For example: higher interest rates → borrowing and consumption become less attractive while saving becomes more attractive → consumption and investment fall → AD shifts left → demand-pull inflation falls, but the scale depends on household debt, confidence, exchange-rate effects and the time lag of mortgage refinancing.
Evaluation that changes the final answer
| Lens | Question to ask | Useful judgement language |
|---|---|---|
| Magnitude and elasticity | How large is the response? | “The outcome is limited if demand/supply is price-inelastic or if the multiplier is small.” |
| Time | Is the short run different from the long run? | “The immediate effect may reverse once contracts, expectations and productive capacity adjust.” |
| Stakeholders | Who gains and who loses? | “Aggregate welfare may rise while lower-income households, workers or small firms bear the adjustment cost.” |
| Constraints | What prevents the policy/mechanism working? | “Effectiveness depends on spare capacity, information quality, implementation cost and institutional credibility.” |
| Alternative explanation | Could another factor dominate? | “The observed change may reflect global commodity prices, confidence or exchange-rate movements rather than the policy alone.” |