Q: Failing to calculate percentage changes before finding elasticities (PED/YED/XED).

Always calculate the percentage change using $ \frac{\text{New Value} - \text{Original Value}}{\text{Original Value}} \times 100 $ for both price and quantity before dividing them. Never directly divide raw unit changes.

Question 1

Omitting the currency unit or magnitude signifier (e.g., 'billion' or 'bn') in final calculation tasks.

Accepted Answer

Always check your final answers against the source table. If the data is presented in 'billion pounds' or 'millions', write the entire unit (e.g., '£19.4bn' instead of '19.4'). Edexcel mark schemes strictly award only 1 mark out of 2 if the currency/magnitude is missing.

Question 2

Confusing a decrease in the rate of inflation (disinflation) with a decrease in the actual price level (deflation).

Accepted Answer

Remember that as long as the inflation rate remains positive (e.g., falling from 5.3% to 4.9%), the average price level is still rising, but at a slower rate. Do not state that prices are falling unless the inflation rate becomes negative.

Question 3

Using generic 'Price' and 'Quantity' labels on macroeconomic aggregate demand / aggregate supply diagrams.

Accepted Answer

For any AD/AS diagram (e.g., showing the impact of oil prices on France), always label the vertical axis as 'Average Price Level' (or 'Price Level') and the horizontal axis as 'Real Output' (or 'Real GDP' / 'Real Income'). Generic labels will cost diagrammatic application marks.

Question 4

Failing to explicitly ground evaluation points in real-world country contexts in Section D essays.

Accepted Answer

To achieve Level 4 marks in Unit 2 or Unit 4 Section D essays, you must refer to real-world country data (e.g., Canada's unemployment, Italy's growth, South Africa's current account deficit, or Argentina's balances). Purely theoretical answers are capped to Level 3.

Question 5

Drawing a maximum price ceiling above the free-market equilibrium or a minimum price floor below it.

Accepted Answer

A maximum price is only binding and effective if set BELOW the market equilibrium, creating excess demand (shortage). A minimum price is only binding if set ABOVE the market equilibrium, creating excess supply (surplus).

Question 6

Representing an ad valorem tax with a parallel supply shift instead of a pivoting supply shift.

Accepted Answer

An ad valorem tax is a percentage-based tax, meaning the absolute tax amount increases as the price increases. You must pivot the supply shift outwards/upwards from the vertical axis so the vertical gap between the curves widens at higher prices.

Question 7

Failing to calculate percentage changes before finding elasticities (PED/YED/XED).

Accepted Answer

Always calculate the percentage change using $ \frac{\text{New Value} - \text{Original Value}}{\text{Original Value}} \times 100 $ for both price and quantity before dividing them. Never directly divide raw unit changes.

Question 8

Omitting the negative sign in PED calculations or failing to interpret its magnitude correctly.

Accepted Answer

Ensure you include the negative sign in your mathematical steps (since price and quantity demanded move in opposite directions). When interpreting, use the absolute value (magnitude) to determine whether demand is elastic ($ > 1 $) or inelastic ($ < 1 $).

試卷	時間	分數	題數	比重	題型
Unit 1: Markets in Action	1小時 45分鐘	80	13	25%	選擇題, Short Answer, Data Response, Extended Essay
Unit 2: Macroeconomic Performance and Policy	1小時 45分鐘	80	13	25%	選擇題, Short Answer, Data Response, Extended Essay
Unit 3: Business Behaviour	2小時	80	13	25%	選擇題, Data Response, Extended Essay
Unit 4: Developments in the Global Economy	2小時	80	13	25%	選擇題, Data Response, Extended Essay

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