The Law of Demand and the Demand Curve

AQA

GCSE

Analysis of the Law of Demand focuses on the inverse relationship between price and quantity demanded, predicated on the ceteris paribus assumption. Candidates must distinguish rigorously between movements along the demand curve (caused by price changes) and shifts of the curve (caused by non-price determinants). Mastery requires explaining the downward slope via the income and substitution effects and the law of diminishing marginal utility, while acknowledging exceptions such as Veblen and Giffen goods.

Objectives

Exam Tips

Pitfalls

Key Terms

Mark Points

What You Need to Demonstrate

Key skills and knowledge for this topic

Award marks for fully labelled diagrams: axes (Price/Quantity), curves (D1/D2), and clear coordinates (P1/Q1 to P2/Q2).
Credit logical chains of reasoning that link a determinant (e.g., rise in income) to the specific mechanism of change (increase in purchasing power leading to a rightward shift).
Candidates must distinguish between 'effective demand' and mere 'want' by referencing ability to pay.
For high-level marks, analysis must explicitly reference the specific context or data provided in the Item (e.g., the specific market for electric vehicles).

Marking Points

Key points examiners look for in your answers

Award marks for fully labelled diagrams: axes (Price/Quantity), curves (D1/D2), and clear coordinates (P1/Q1 to P2/Q2).
Credit logical chains of reasoning that link a determinant (e.g., rise in income) to the specific mechanism of change (increase in purchasing power leading to a rightward shift).
Candidates must distinguish between 'effective demand' and mere 'want' by referencing ability to pay.
For high-level marks, analysis must explicitly reference the specific context or data provided in the Item (e.g., the specific market for electric vehicles).

Examiner Tips

Expert advice for maximising your marks

💡Always use a ruler for diagrams; freehand curves that lack precision will be penalised.
💡When explaining a shift, use the acronym PASIFIC (Population, Advertising, Substitutes, Income, Fashion, Interest rates, Complements) to recall factors.
💡Explicitly state 'ceteris paribus' when isolating the impact of a price change.
💡In 9-mark analysis questions, ensure the chain of reasoning includes at least three logical steps (Cause -> Mechanism -> Outcome).

Common Mistakes

Pitfalls to avoid in your exam answers

Confusing a 'movement along the curve' (caused by price change) with a 'shift of the curve' (caused by non-price factors).
Labelling the x-axis as 'Price' and y-axis as 'Quantity' (mathematical inversion error).
Stating that a change in the price of a substitute causes a movement along the demand curve for the original good.
Failing to use the ceteris paribus assumption when analysing a single variable change.

Key Terminology

Essential terms to know

Likely Command Words

How questions on this topic are typically asked

State

Calculate

Explain

Analyse

Discuss

Evaluate

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