Economics Cambridge A Level Notes
Overview of the Syllabus
Components of the Economics syllabus include:
7. The price system and the microeconomy
8. Government microeconomic intervention
9. The macroeconomy
Government macroeconomic intervention
International economic issues
Chapter 30: Utility
Learning Objectives
Define total utility and marginal utility.
Calculate total utility and marginal utility.
Explain diminishing marginal utility.
Explain the equi-marginal principle.
Derive an individual demand curve.
Evaluate the limitations of marginal utility and assumptions of rational behavior.
30.1 Utility and Diminishing Marginal Utility
Utility: The satisfaction derived from consumption, measured in units (utils).
Marginal Utility (MU): Additional utility derived from the consumption of one more unit. MU = \frac{\Delta TU}{\Delta Q}
Total Utility (TU): Overall satisfaction derived from consuming all units of a good over time.
Law of Diminishing Marginal Utility: States that as more of a good is consumed, the additional satisfaction derived from each extra unit decreases.
Example:
1st slice of pizza: Willing to pay \$5, yields 10 units.
2nd slice: Willing to pay \$4, yields 7 units.
3rd slice: Willing to pay \$3, yields 3 units.
Consumers optimize purchasing behavior based on equating the marginal utility per dollar spent across all goods.
30.2 The Equi-Marginal Principle
A consumer maximizes utility when: \frac{MUx}{Px} = \frac{MUy}{Py}
Example Analysis (Px = \$1, Py = \$2, Budget = \$10):
| Q | MUx | MUx / Px | MUy | MUy / Py |
| :--- | :--- | :--- | :--- | :--- |
| 1 | 60 | 60 | 50 | 25 |
| 2 | 40 | 40 | 44 | 22 |
| 3 | 25 | 25 | 36 | 18 |
| 4 | 18 | 18 | 20 | 10 |
| 5 | 14 | 14 | 14 | 7 |Allocation: Consumer buys 4 units of X (\$4) and 3 units of Y (\$6).
Check: \frac{MUx}{Px} = 18 and \frac{MUy}{Py} = 18. Total Utility = (60 + 40 + 25 + 18) + (50 + 44 + 36) = 273 utils.
30.3 Derivation of an Individual Demand Curve
The price a consumer is willing to pay corresponds to the MU of that unit. As MU falls, the price the consumer is willing to pay falls, creating a downward-sloping demand curve.
30.4 Limitations of Marginal Utility Theory
Measurement: Difficulty in quantifying utility (cardinal measurement).
Rationality: Assumptions of perfect information and constant calculation.
Income/Substitution Effects: Changes in price affect real income, not just relative price.
Chapter 31: Indifference Curves and Budget Lines
31.1 Indifference Curves
Shows combinations of two goods that give the same level of satisfaction.
Marginal Rate of Substitution (MRS): The rate at which a consumer is willing to substitute one good for another. MRS = \frac{\Delta Qy}{\Delta Qx}.
31.2 Budget Line
Represents all combinations of goods affordable with a fixed income (I). Equation: I = (Px \cdot Qx) + (Py \cdot Qy).
Shifts outward with increased income; rotates with price changes.
Chapter 32: Efficiency and Market Failure
32.1 Economic Efficiency
Productive Efficiency: Producing at the lowest point on the ATC curve (P = MC is not a requirement here, but ATC is minimized).
Allocative Efficiency: P = MC. Resources are allocated according to consumer preferences.
Pareto Optimality: No one can be made better off without making someone else worse off.
32.2 Market Failure
Occurs when social welfare is not maximized. Causes include:
Externalities: Divergence between private and social costs/benefits.
Public Goods: Non-excludable and non-rivalrous.
Information Asymmetry: One party lacks knowledge (Adverse Selection/Moral Hazard).
Chapter 33: The Labor Market
33.1 Demand for Labor
Marginal Revenue Product (MRP): The extra revenue a firm gains by employing one more worker. MRP = MPP \cdot MR, where MPP is Marginal Physical Product.
Factors shifting demand: Productivity, price of the final product, and cost of capital (substitutes).
33.2 Supply of Labor
Determined by workers' trade-off between leisure and wages.
Substitution Effect: Higher wages make leisure more expensive, leading to more work.
Income Effect: Higher wages increase income, leading to a demand for more leisure (backward-bending supply curve).
33.3 Wage Determination
Perfect Competition: Wage is set by the market where DL = SL.
Monopsony: A single buyer of labor. They hire where MRP = MCL (Marginal Cost of Labor).
Chapter 34: Government Intervention in the Microeconomy
34.1 Correcting Market Failure
Indirect Taxes: To correct negative externalities (e.g., carbon tax). Shifts supply curve left.
Subsidies: To encourage positive externalities (e.g., education). Shifts supply curve right.
Direct Provision: Providing public goods (national defense).
34.2 Price Controls
Maximum Price (Ceiling): Set below equilibrium to help consumers; can lead to shortages.
Minimum Price (Floor): Set above equilibrium (e.g., Minimum Wage); can lead to surpluses.
Chapter 35: The Macroeconomy: Measurement
35.1 National Income Statistics
Gross Domestic Product (GDP): Total value of goods/services produced in a country in a year.
Gross National Income (GNI): GDP plus net income from abroad.
Real vs. Nominal: Real GDP = \frac{Nominal GDP}{GDP Deflator} \cdot 100.
35.2 PPP (Purchasing Power Parity)
Adjusts GDP to reflect the different costs of living and inflation rates in different countries.
Chapter 36: Circular Flow of Income and AD/AS
36.1 Circular Flow
Injections (J): Investment (I), Government Spending (G), Exports (X).
Leakages (W): Savings (S), Taxes (T), Imports (M).
Equilibrium occurs when J = W.
36.2 Aggregate Demand (AD)
AD = C + I + G + (X - M).
The downward slope is due to the wealth effect, interest rate effect, and international trade effect.
36.3 Aggregate Supply (AS)
Short-run (SRAS): Upward sloping, influenced by costs of production (wages, raw materials).
Long-run (LRAS): Vertical (Classical view) or curved (Keynesian view) representing the full employment level of output (Y_f).