Classifying firms: size and sector
Firms differ in size — measured by the number of workers, the value of output, the capital employed, or market share. They also work in different sectors: primary (extracting raw materials, e.g. farming, mining), secondary (manufacturing and construction) and tertiary (services such as banking, retail, transport). A single industry usually contains both small and large firms side by side.
Economies of scale lower average cost
Economies of scale are cost advantages as output rises, shown by a fall in average cost (AC = total cost ÷ quantity). Internal economies arise within the firm: technical (large machinery), purchasing/financial (bulk discounts, cheaper loans), managerial (specialist managers) and risk-bearing (a wider range). External economies come from the whole industry growing in an area (skilled local labour, shared suppliers) and lower average cost for every firm.
Diseconomies of scale raise cost
Diseconomies of scale are the cost disadvantages of growing too big, shown by a rise in average cost beyond a certain output. The main causes are managerial (the firm is hard to control, decisions slow), communication problems (messages distorted across many layers) and poor worker motivation in a large, impersonal firm. Because of these, some firms choose to stay small.
Internal vs external growth
Internal (organic) growth means a firm sells more of its own output (e.g. more branches). External growth joins another firm by merger or takeover (integration). Horizontal integration joins firms at the same stage of the same industry (two coffee chains). Vertical integration joins different stages of one industry (buying a farm is backward; buying cafes is forward). Conglomerate integration joins unrelated industries, spreading risk.
Drawn from real examiner reports.
Small firm: give the consumer drawback too
Asked whether small firms benefit consumers, give both sides. Benefits: personal, flexible service and, in a competitive market, lower prices and good quality. Drawbacks: they cannot gain economies of scale (so prices may be higher) and offer limited choice. Do not drift into the effect on the wider economy or employment — that is off the question.
June 2024 Paper 2 Q1(g): strong answers gave a range of consumer benefits (personal service, flexibility, competitive prices), but the reasons a small firm might NOT benefit consumers were done less well, and weaker answers drifted into the impact of small firms on the economy or employment, which was outside the scope of the question.
Merger: explain the effect, not just the type
A merger is two firms joining into one. For full credit, be clear which kind — a horizontal merger joins firms in the same industry at the same stage of production — and explain its effect: reduced competition and greater monopoly power, which can mean higher prices, lower quality and less choice. Naming the type alone is not enough.
June 2024 Paper 2 Q4(c): most candidates understood the term merger but explanations were often too vague and did not make clear the two firms were in the same industry at the same stage of production; stronger answers linked to market failure, lack of competition and monopoly power meaning higher prices, lower quality and less choice. In June 2023 Paper 2 Q(d) weaker answers only stated types of merger such as horizontal or vertical without a clear explanation.
Internal vs external economies of scale
An internal economy of scale comes from the growth of the firm itself; an external economy comes from the growth of the whole industry and lowers average cost for every firm in it (it shifts the whole cost curve down). When explaining an economy of scale, always name a specific type as an example — technical, financial, purchasing.
November 2023 Paper 2 Q(b): candidates who understood the question referred to economies of scale were usually successful, but an explanation PLUS an example such as financial economies of scale was needed for full marks. November 2024 Paper 1 confirmed that EXTERNAL economies of scale shift the whole average-total-cost curve, in contrast with internal economies.
Economies grow firms, diseconomies limit them
Get the direction right. Internal economies of scale encourage a firm to grow, because average cost keeps falling as output rises. Diseconomies of scale make a firm stop growing or stay small, because average cost starts to rise once it is too big. Do not swap the two.
June 2023 Paper 1 (Multiple Choice) Q14: firms are encouraged to grow when there are internal economies of scale but tend to stay small or stop growing when there are diseconomies of scale (only 34 per cent correct).
The three types of integration
Keep the integration types apart. Horizontal = same industry, same stage (two cafes). Vertical = same industry, different stages — backward towards the raw material (a cafe buys a farm), forward towards the customer (a farm buys cafes). Conglomerate = unrelated industries. Muddling these, or the backward/forward direction, loses marks.
AC = total cost divided by quantity
When calculating average cost (or average revenue), always divide by the quantity: AC = total cost ÷ quantity. A common slip is to forget the division or to divide by the wrong figure. A falling average cost as output rises is what an economy of scale looks like.
November 2023 Paper 2 Q(b): the report noted that average revenue and average cost must be divided by quantity.
Discuss: both sides, avoid reverse reasoning
Part (d) rewards analysis (AO2) and evaluation (AO3). Give chains on both sides (a merger gains economies of scale but cuts competition and may raise prices), then a justified judgement. Avoid reverse reasoning (flipping a benefit without explanation).
Explain the effect, not just the label
For any firm term — a merger type, an economy of scale — do not stop at the name. Follow it with its consequence: a horizontal merger → less competition → higher prices; a purchasing economy → bulk discounts → lower average cost. The mark is for the effect, not the label.
Match depth to the command word
Paper 2 climbs a ladder: (a) define (2) — a precise sentence, (b) explain (4) — reasons developed, (c) analyse (6) — a cause-and-effect chain, (d) discuss (8) — both sides plus a judgement. Match effort to the command word; do not over-write or under-develop.
Firms can be grouped in two main ways.
By size — measured by:
By sector:
| Sector | What it does | Examples |
|---|---|---|
| Primary | Extracts raw materials | Farming, fishing, mining |
| Secondary | Manufactures and builds | Car factory, bakery, construction |
| Tertiary | Provides services | Banking, retail, transport |
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