OxfordAQA International GCSE Economics: Costs, revenue, productivity and scale (9214) – Revision Notes

These notes condense section 3.1.4 (Production, costs, revenue and profit) of Topic 1, How markets work, in the OxfordAQA International GCSE Economics (9214) specification, for exams from May/June 2025 onwards. For full explanations read the study guide, then test yourself with the practice questions. Also useful: the course hub, the checklist and the free diagnostics. Every figure is made up, and money is in an unnamed currency unit.

3.1.4.1 Key definitions

Term	Meaning
Business objective	The aim the firm sets itself: profit, sales growth, market share
Market share	Firm’s sales divided by market sales, times 100
Fixed cost	Does not alter as output alters in the short run (rent, loan repayment)
Variable cost	Changes with output (materials, packaging, piece-rate pay)
Revenue	Money a firm earns by selling
Profit	Total revenue minus total cost
Production	Total quantity made
Productivity	Output per worker (or per hour)
Economies of scale	Unit cost drops as the firm raises output
Diseconomies of scale	Unit cost climbs once the firm has grown too large

Formulas

Quantity	Formula
Total cost (TC)	TFC + TVC
Average fixed cost (AFC)	divide TFC by units made
Average variable cost (AVC)	divide TVC by units made
Average cost (ATC)	divide TC by units made; equals AFC + AVC
Total revenue (TR)	price x units sold
Average revenue (AR)	divide TR by units sold; with a single selling price this is just that price
Profit	TR - TC (a loss if below zero)
Profit per unit	price - ATC
Market share	firm’s sales / market sales x 100
Productivity	output divided by workers employed (or by hours worked)
Percentage change	change divided by the original, times 100

Method in steps: a cost-and-profit table

1. Find TC for each output: TFC + TVC.
2. Divide each cost by output to get AFC, AVC and ATC, then confirm ATC = AFC + AVC.
3. Find TR = price x output.
4. Profit = TR - TC. Negative means loss.
5. Say where profit begins (the first output where TR is above TC).

Worked reminders

Costs and profit (a small print shop). TFC = 900, TVC = 2,100, output = 300 posters, price 14. TC = 900 + 2,100 = 3,000. ATC = 3,000 / 300 = 10. AFC = 900 / 300 = 3. AVC = 2,100 / 300 = 7. TR = 14 x 300 = 4,200. Profit = 4,200 - 3,000 = 1,200.

Raising profit. Profit rises if average cost falls, or revenue rises. At 300 posters, cutting ATC by 0.80 adds 0.80 x 300 = 240 to profit.

Price incentive. Unit cost 10. At price 14, profit per unit is 4. At price 17, it is 7. Higher profit per unit gives producers an incentive to expand output, which is why supply slopes upwards.

Productivity versus production. 15 workers make 90 units (6.0 each). Then 18 workers make 99 units (5.5 each). Production rose 10%. Productivity fell (5.5 - 6.0) / 6.0 x 100 = -8.3%.

Market share and sales growth. A market grows from 40,000 to 44,000 units. A firm’s sales rise from 6,000 to 7,150. Share before = 6,000 / 40,000 x 100 = 15%. Share after = 7,150 / 44,000 x 100 = 16.25%. Sales growth = (7,150 - 6,000) / 6,000 x 100 = 19.2%. Market growth = 10%. The firm grew faster than the market, so its share rose.

Economies of scale from a table. Total cost is 24,000 at 2,000 units, 33,000 at 3,000 units and 52,000 at 4,000 units. Average cost: 12.00, 11.00, then 13.00. Average cost falls from 2,000 to 3,000 units (economies of scale, a fall of 8.3%), then rises to 13.00 at 4,000 units (diseconomies of scale, a rise of 18.2%). Always read the change in average cost, not in total cost, which rises throughout.

Objectives and ethics

• Profit: surplus after costs. Sales growth: more units or revenue over time. Market share: slice of the market.
• Objectives can clash: low prices raise sales and share but cut profit per unit.
• Ethical conflicts: low pay, unsafe conditions, pollution, misleading advertising, poor treatment of suppliers.
• Responses: ethical codes, fair wages, safer processes, cleaner production, open reporting, obeying regulations.
• Evaluation: ethical behaviour may raise costs short run but protect reputation, loyalty and recruitment long run; the effect depends on how price-sensitive customers are and how competitive the market is.

Productivity: factors and benefits

• Factors: capital and technology; skills, training, education and health; motivation and management; working conditions; specialisation and division of labour; quality of materials and organisation.
• Benefits: lower average cost per unit; room for higher wages or profit; ability to cut price or compete better; more output from limited resources; growth for the economy.
• Link: higher productivity lowers labour cost per unit. A worker paid 600 a week making 120 units costs 5.00 a unit; making 150 units costs 4.00.

3.1.4.3 Economies and diseconomies of scale

Type	One-line reason
Managerial	Specialist managers do each job better
Purchasing	Bulk buying earns discounts
Financial	Lower interest rates and easier loans for a large firm
Technical	Large machines and mass-production methods lower unit cost
Risk-bearing	Many products and markets spread risk

Diseconomies of scale: communication and coordination problems, slow decisions, workers feel remote and lose motivation, loss of managerial control.

Effects on behaviour: firms seek growth, cut prices, aim for market share, and may make it hard for small rivals to compete. Small firms may specialise or merge.

Costs and benefits of growth: benefits are lower average cost, higher sales and profit, share, risk spread and supplier bargaining power. Costs are funding needs, diseconomies, harder management and unused capacity if demand falls.

Chains of reasoning to learn

• Training lifts productivity, so each worker makes more, so the wage cost of each unit drops, so average cost drops and profit per unit grows (price unchanged).
• Bulk buying cuts the price paid per unit of material, so variable cost per unit falls, so average cost falls: a purchasing economy of scale.
• A firm grows too large, so messages pass through many layers, so decisions slow and errors rise, so average cost rises: diseconomies of scale.
• A cheaper but harmful process lowers cost now, but may bring fines, bad publicity and lost customers, so the long-run effect on profit is uncertain.

Must-know distinctions

• Fixed versus variable costs; total versus average costs.
• Revenue versus profit.
• Production versus productivity.
• Economies of scale (average cost falls with scale) versus a fall in AFC at higher output within one plant.
• Economies of scale versus diseconomies of scale.
• Higher price (supply response along the curve) versus a shift of supply.
• A cut in average cost from a better process (productivity) versus a cut from a larger scale (economies of scale).

Quick self-test

1. TFC is 900, TVC is 2,100 and output is 300. Find TC, AFC and AVC.
2. A shop sells 360 items at price 12. TC is 3,600. Find TR, profit and ATC.
3. TR is 4,500 from 750 units. Find AR.
4. A firm’s sales are 12,000 in a market of 80,000. Find market share.
5. TFC is 4,500. Find AFC at 300 units and at 900 units.
6. Name the five types of economy of scale in the specification.
7. Average cost falls from 6.00 at 20,000 units to 5.40 at 30,000 units. Find the percentage change and name the effect.
8. Give two causes of diseconomies of scale.
9. ATC falls by 0.80 on 500 units. What is the effect on profit?
10. With unit cost unchanged, why does a rise in price encourage producers to supply more?
11. Give one ethical conflict and one way a firm could respond.

Answers

1. TC = 900 + 2,100 = 3,000. AFC = 900 / 300 = 3. AVC = 2,100 / 300 = 7.
2. TR = 12 x 360 = 4,320. Profit = 4,320 - 3,600 = 720. ATC = 3,600 / 360 = 10.
3. AR = 4,500 / 750 = 6.
4. 12,000 / 80,000 x 100 = 15%.
5. 4,500 / 300 = 15. 4,500 / 900 = 5.
6. Managerial, purchasing, financial, technical, risk-bearing.
7. (5.40 - 6.00) / 6.00 x 100 = -10%. Economies of scale.
8. Any two: communication problems, poor coordination, slow decisions, workers feel remote and lose motivation, loss of control.
9. Profit rises by 0.80 x 500 = 400.
10. Higher price with the same cost means more profit per unit, so producers gain from supplying more and will use more resources to do so.
11. For example, polluting a river to save waste costs; response: invest in cleaner treatment or follow tighter rules.

Where marks are usually lost

• Mixing up total and average figures, for example reporting AC when asked for TC.
• Writing profit as TR + TC, or forgetting that a result below zero is a loss.
• Giving only the type of economy of scale, such as “purchasing”, with no reason for lower average cost.
• Claiming productivity rose because output rose, when the number of workers also rose.
• Leaving out units or the percentage sign, or rounding too early.
• Listing ethical problems without saying how a producer might respond.
• Using diseconomies of scale as the same thing as rising variable costs in the short run.
• One-sided answers on growth: give a cost to set against each benefit and reach a judgement.

Official syllabus

OxfordAQA International GCSE Economics (9214), version 1.0, for exams from May/June 2025 onwards, published by OxfordAQA. Sections 3.1.4.1, 3.1.4.2 and 3.1.4.3.