AQA A-level Economics: Production, productivity, specialisation and returns (7136)

This guide follows the AQA AS and A-level Economics specification (version 1.3, 29 June 2022) for AQA A-level Economics (7136). It covers three sub-sections of the production, costs and revenue content: Production and productivity (3.1.4.1), Specialisation, division of labour and exchange (3.1.4.2), and The law of diminishing returns and returns to scale (3.1.4.3). The specification PDF prints the A-level content as sections 4.1.4.1 to 4.1.4.3; the AQA website numbers it 3.1.4.1 to 3.1.4.3. Every firm, country and figure below is invented for illustration.

Related pages: revision notes, practice questions, the course hub, the printable checklist, the wider individuals, firms, markets and market failure guide and the free diagnostics. Costs of production, economies of scale, revenue and profit belong to other sub-sections, so they are left out.

What you must be able to do

Sub-section	You must be able to
Production and productivity (3.1.4.1)	Explain production as the conversion of inputs, or the services of factors of production such as capital and labour, into final output. Define productivity, including labour productivity, and calculate it
Specialisation, division of labour and exchange (3.1.4.2)	Explain the benefits of specialisation and division of labour. Explain why specialisation needs an efficient means of exchange, such as money as a medium of exchange
Diminishing returns and returns to scale (3.1.4.3)	Distinguish the short run from the long run; marginal, average and total returns; state the law of diminishing returns; distinguish increasing, constant and decreasing returns to scale; link both ideas to costs

1. Production and productivity

Production converts inputs into final output. The inputs are the services of four factors of production: land, labour, capital and enterprise. A tile maker turns clay, labour hours, the kiln and the press into finished tiles. The same word covers goods and services, so a dental surgery also produces.

Productivity is output per unit of input. Labour productivity is output per worker, or output per worker-hour. Per worker-hour is the better measure when hours change, because a firm can raise output per worker simply by making people work longer.

Labour productivity = total output ÷ number of workers (or ÷ total hours worked)

Worked example 1: Kiln Street Tiles (illustrative firm).

Year	Output (tiles a week)	Workers	Hours each	Total hours
1	14,400	12	40	480
2	19,800	12	36	432
3	36,000	24	36	864

Year 1: 14,400 ÷ 12 = 1,200 tiles per worker; 14,400 ÷ 480 = 30 tiles per hour. Year 2: 19,800 ÷ 12 = 1,650 per worker; 19,800 ÷ 432 = 45.83 per hour. Change in output per worker: (1,650 − 1,200) ÷ 1,200 × 100 = +37.5%. Change in output per hour: (45.83 − 30) ÷ 30 × 100 = +52.8%. Year 2 hours fell, so the per-hour rise is larger. A new press explains the gain: more capital per worker.

Year 3: output rises 81.8% from year 2, but 36,000 ÷ 24 = 1,500 per worker, a fall of 9.1%. Output rose because the firm hired more labour, not because labour became more productive.

Evaluation link. Higher productivity comes from more or better capital, better skills, better organisation and better technology. Productivity is not output. Check whether a rise in output came from more inputs or from more output per input.

2. Specialisation and division of labour

Specialisation means a person, firm, region or country concentrating on the tasks or goods it does best. Division of labour is specialisation within production: a job is split into tasks and each worker does one task.

Benefits (apply these to the context in the question):

• Skill. Repeating one task builds speed and accuracy.
• Time. No time is lost moving between tasks and tools.
• Capital use. Each worker keeps one machine busy, so it is not idle.
• Matching. People can be placed where their strengths are.
• Higher output per worker, which can lower unit costs and widen choice.

Worked example 2: Orchard Lane Preserves (illustrative firm). Four workers make jam. Each worker works 480 minutes a day.

Before: every worker does all four stages (prepare fruit, cook, jar, label). One jar takes 40 minutes including switching. Jars per worker: 480 ÷ 40 = 12. Total: 4 × 12 = 48 jars.

After: each worker takes one stage and gets quicker. A jar now passes each stage in 7.5 minutes. Each stage makes 480 ÷ 7.5 = 64 jars, so the line makes 64 jars: 64 ÷ 4 = 16 per worker. Gain per worker: (16 − 12) ÷ 12 × 100 = +33.3%. All four stages take the same time, so none holds up the others.

Costs and limits (use these to evaluate).

• Repetitive work can bore workers, raising absenteeism and staff turnover.
• Workers depend on each other. If one stage stops, the line stops.
• Narrow skills make workers harder to move if demand changes.
• Gains stop when tasks cannot be split further, or when checking and handling between stages costs more time than it saves.

Why specialisation needs exchange

A specialist makes one thing but wants many. Specialisation therefore only works if people can swap output for what they need.

Barter needs a double coincidence of wants: each side of a swap must hold the good the other side is after. Barter also lacks a common unit for prices. With n goods there are n(n − 1) ÷ 2 exchange rates.

Goods	Barter exchange rates	Money prices
5	5 × 4 ÷ 2 = 10	5
12	12 × 11 ÷ 2 = 66	12
40	40 × 39 ÷ 2 = 780	40

Money as a medium of exchange is generally accepted in payment for goods and services. It removes the double coincidence of wants, so a baker sells loaves for money and buys shoes with it. One price per good makes comparison simple. This saves search time and lets people specialise further. That is the link to the specification: specialisation needs an efficient means of exchange.

3. Short run, long run and returns to a factor

Short run: the period during which some factor of production cannot be changed. Long run: a period in which all factors can be varied. These are not set numbers of months. A market stall’s long run might be a week; an oil refinery’s might be years.

Returns to a variable factor apply in the short run. Hold capital fixed and add labour.

• Total returns (total product, TP): total output.
• Average returns (average product, AP): TP ÷ number of workers.
• Marginal returns (marginal product, MP): the extra output from one more worker, so TP(n) − TP(n − 1).

The law of diminishing returns: keep adding units of a variable factor to a fixed amount of another factor, and at some point each extra unit adds less to output than the one before.

Worked example 3: Fernbank Nursery (illustrative firm). One greenhouse is fixed. The output is trays of seedlings a day. The wage is £96 a day.

Workers	TP	MP	AP	MC (£96 ÷ MP)	AVC (£96 × workers ÷ TP)
1	10	10	10.00	9.60	9.60
2	26	16	13.00	6.00	7.38
3	48	22	16.00	4.36	6.00
4	62	14	15.50	6.86	6.19
5	72	10	14.40	9.60	6.67
6	78	6	13.00	16.00	7.38
7	78	0	11.14	not defined	8.62
8	75	−3	9.38	not defined	10.24

Working for worker 4: MP = 62 − 48 = 14; AP = 62 ÷ 4 = 15.5; MC = 96 ÷ 14 = £6.86.

Reading the table:

• Increasing marginal returns for workers 1 to 3: MP rises as workers share tasks.
• Diminishing marginal returns begin with worker 4, where MP falls from 22 to 14. TP still rises, but more slowly.
• Diminishing average returns also begin with worker 4: AP falls from 16.00 to 15.50. AP falls when MP is below AP.
• TP is highest at 78 (workers 6 and 7). MP is 0 for worker 7. MP is negative for worker 8: the greenhouse is overcrowded.

Sketch of MP against workers, described in words: the horizontal axis is workers and the vertical axis is MP. The curve climbs from 10 to a peak of 22 at worker 3, then falls through 14, 10, 6 and 0, and dips below the axis at worker 8 (−3). It is hill-shaped, and the peak marks where diminishing marginal returns begin.

Why diminishing returns happens. The fixed factor becomes scarce per worker: workers queue for the same benches and tools. It is a property of the technology and the fixed factor, not of lazy workers.

Link to costs. The wage is constant, so extra cost per tray is wage ÷ MP. A rising MP pulls MC down, and a falling MP pushes it up. AVC is wage ÷ AP, so it moves opposite to AP. In the table the lowest MC (worker 3) and the lowest AVC (worker 3) follow the highest MP and highest AP. This is how the specification’s cost implication arises. The costs page covers the full cost curves.

4. Returns to scale

Returns to scale compare the proportional change in output with an equal proportional change in all inputs. This is a long-run idea.

If output rises by…	Returns to scale
a larger proportion than inputs	Increasing
the same proportion as inputs	Constant
a smaller proportion than inputs	Decreasing

Worked example 4: Tern Moulding (illustrative firm). Machines and workers are scaled together. Scale 1 is two machines and ten workers, and costs £2,000 a week.

Scale	Output	Input change	Output change	Returns to scale	Cost per unit (£)
1	1,000				2.00
2	2,300	+100%	+130%	Increasing	1.74
3	3,600	+50%	+56.5%	Increasing	1.67
4	4,800	+33.3%	+33.3%	Constant	1.67
5	5,500	+25%	+14.6%	Decreasing	1.82

Check scale 5: (5,500 − 4,800) ÷ 4,800 × 100 = 14.6%. Cost per unit at scale 5: £10,000 ÷ 5,500 = £1.82.

Implication for costs. If input prices do not change, increasing returns to scale lower long-run cost per unit, constant returns hold it level, and decreasing returns raise it. The reasons firms gain or lose from size are covered in the costs and economies of scale sub-section.

Diminishing returns versus returns to scale

	Diminishing returns	Returns to scale
Time period	Short run	Long run
Inputs	One factor varied, others fixed	All factors varied together
Question	What happens to MP?	What happens to total output?

Both explain the link between inputs and output. A firm can have diminishing returns in the short run and increasing returns to scale in the long run.

Common errors

• Saying productivity is output. It is output per unit of input.
• Using output per worker when hours changed and the question gives hours.
• Saying diminishing returns means total output falls. It means MP falls; TP can still rise.
• Applying the law of diminishing returns when all factors increase.
• Saying money is only a store of wealth. The specification asks about it as a medium of exchange.
• Listing benefits of specialisation without applying them to the firm in the question.

Official syllabus

AQA AS and A-level Economics specification, version 1.3, 29 June 2022, published by AQA. Content: Production and productivity, Specialisation, division of labour and exchange, and The law of diminishing returns and returns to scale.