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

Condensed recall notes for AQA A-level Economics (7136), based on the AQA AS and A-level Economics specification (version 1.3, 29 June 2022). They cover 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 PDF prints these as 4.1.4.1 to 4.1.4.3. For full explanations, use the study guide, then test yourself with the practice questions. See also the course hub, the printable checklist, the microeconomics revision notes and the free diagnostics. All data below is invented for illustration.

Definitions to learn word for word

Term	Definition
Production	Converting inputs, or the services of factors of production such as capital and labour, into final output
Productivity	Output per unit of input
Labour productivity	Output per worker, or output per worker-hour
Specialisation	Concentrating on the tasks or goods you do best
Division of labour	Breaking production into separate tasks, with one worker per task
Medium of exchange	Something generally accepted in payment for goods and services
Short run	The period in which some factor cannot be changed
Long run	The period in which every factor can be changed
Law of diminishing returns	With another factor held fixed, each extra unit of a variable factor eventually adds less to output than the last
Returns to scale	The change in output when all inputs change by the same proportion

Productivity

Labour productivity = output ÷ workers, or output ÷ total hours worked.

Method in steps

1. Find total hours: workers × hours each.
2. Divide output by workers or hours, as asked.
3. Percentage change = (new − old) ÷ old × 100.
4. Compare with the change in output and inputs before you comment.

Worked reminder: Country A (illustrative).

	Output (units, billions)	Hours (billions)	Output per hour
Year 1	600	20.0	30.00
Year 2	636	20.4	31.18

Output rose by 6%. Hours rose by 2%. Output per hour rose by (31.18 − 30) ÷ 30 × 100 = 3.9%. Part of the growth in output came from more hours, and part from more output per hour.

Why productivity rises: more or better capital, training, better organisation, new technology, better health. Why it matters: it allows higher output without more inputs, and can reduce costs per unit.

Specialisation, division of labour and money

Benefits	Costs and limits
Skill grows from repetition	Boredom, absenteeism, turnover
No time lost switching tasks	One stage stopping halts the line
Capital is kept in use	Workers become less adaptable
Workers are matched to tasks	Gains end when tasks cannot be split further
Output per worker rises, so unit cost can fall	Checking and handling between stages take time

Why exchange is needed. A specialist makes little of what they consume. Barter needs a double coincidence of wants (each party holds what the other wants) and has no common unit of account. Barter exchange rates: n(n − 1) ÷ 2. Money as a medium of exchange removes the double coincidence of wants, saves search time and gives one price per good.

Goods	Barter exchange rates	Money prices
8	8 × 7 ÷ 2 = 28	8
20	20 × 19 ÷ 2 = 190	20

Chain of reasoning. Division of labour → more skill and less switching → higher output per worker → lower cost per unit and more output to sell → needs a reliable means of exchange → money makes trade fast and cheap → more specialisation is possible.

Returns to a variable factor (short run)

Term	Meaning	Formula
Total returns	Total output (TP)
Average returns	Output per worker (AP)	TP ÷ workers
Marginal returns	Extra output from the last worker (MP)	TP(n) − TP(n − 1)

Worked reminder: a car valet bay (illustrative). One bay is fixed. The wage is £80 a day. The output is cars cleaned a day.

Workers	TP	MP	AP	MC (£80 ÷ MP)	AVC (£80 × workers ÷ TP)
1	5	5	5.00	16.00	16.00
2	14	9	7.00	8.89	11.43
3	26	12	8.67	6.67	9.23
4	34	8	8.50	10.00	9.41
5	38	4	7.60	20.00	10.53
6	38	0	6.33	not defined	12.63

• Diminishing marginal returns start at worker 4 (MP falls from 12 to 8).
• AP falls from worker 4 as well, because MP (8) is below AP (8.67).
• TP is still rising from worker 4 to worker 5. It stops rising at worker 6.
• MC and AVC are lowest at 3 workers, where MP and AP are highest.

Rules to remember

• MP above AP: AP rises. MP below AP: AP falls. MP crosses AP at AP’s maximum.
• Diminishing returns means MP falls. It does not mean TP falls.
• Wage constant: MC = wage ÷ MP and AVC = wage ÷ AP.

Returns to scale (long run)

Output rises by…	Returns to scale	Cost per unit if input prices are constant
more than inputs	Increasing	Falls
same as inputs	Constant	Unchanged
less than inputs	Decreasing	Rises

Worked reminder: a delivery fleet (illustrative). The fleet is 4 vans and 4 drivers, and delivers 200 parcels a day. Both are doubled to 8 vans and 8 drivers, and the fleet delivers 380 parcels. Inputs rose 100%. Output rose (380 − 200) ÷ 200 × 100 = 90%. Output rose by less than inputs, so returns to scale are decreasing.

Must-know distinctions

	Diminishing returns	Returns to scale
Period	Short run	Long run
Inputs	One variable, others fixed	All change together
Measures	MP, AP, TP	Total output against inputs
Cost link	MC rises (AVC follows once MP is below AP)	Long-run cost per unit falls, stays flat or rises

Other pairs: productivity and output; marginal and average; specialisation and division of labour (division of labour is specialisation inside a firm).

Evaluation points

• Is division of labour always good? It helps most in repetitive tasks with high volume. Where work needs creativity or flexibility, narrow roles can cut quality and motivation.
• Is the short run a fixed time? No. It depends on how long it takes to change the fixed factor, so a bakery stall adapts faster than a steelworks.
• Does a rise in output show a rise in productivity? No. Compare output with the inputs used.

Quick self-test

1. Define labour productivity.
2. A workshop makes 2,400 units with 30 workers, then 2,700 units with the same 30 workers. Find the percentage change in output per worker.
3. A firm makes 5,400 pieces with 45 workers who each work 8 hours. Find output per worker-hour.
4. How many barter exchange rates exist among 20 goods?
5. Why does specialisation need a medium of exchange?
6. Say what is true of factors of production in the short run.
7. TP is 70 with 5 workers and 72 with 6 workers. Find MP of the sixth worker, and AP at 5 and at 6 workers.
8. State the law of diminishing returns in your own words.
9. All inputs double and output goes from 120 to 264. State the percentage change in output and the type of returns to scale.
10. The wage is £60 a day and a worker’s MP is 15. Find the extra cost per unit of output.
11. True or false: diminishing returns means total output must fall.

Answers

1. Output per worker, or per worker-hour.
2. 2,400 ÷ 30 = 80; 2,700 ÷ 30 = 90; (90 − 80) ÷ 80 × 100 = 12.5%.
3. Hours = 45 × 8 = 360; 5,400 ÷ 360 = 15 pieces per hour.
4. 20 × 19 ÷ 2 = 190.
5. A specialist makes little of what they want to consume, so they must trade. Barter needs a double coincidence of wants. Money removes it.
6. At least one factor is fixed.
7. MP = 72 − 70 = 2. AP at 5 = 70 ÷ 5 = 14. AP at 6 = 72 ÷ 6 = 12.
8. With another factor fixed, each extra unit of the variable factor eventually adds less than the previous one.
9. (264 − 120) ÷ 120 × 100 = 120%, which exceeds the 100% rise in inputs: increasing returns to scale.
10. 60 ÷ 15 = £4.
11. False. MP falls. TP still rises while MP is positive.

Where marks are usually lost

• Writing “productivity” when the answer needs output per worker-hour.
• Dividing by workers when the question gives hours and the hours changed.
• Reading higher output as higher productivity.
• Placing diminishing returns in the long run.
• Saying total product falls when marginal product falls.
• Confusing diminishing returns with decreasing returns to scale.
• Listing benefits of division of labour without linking them to the firm in the question.
• Explaining money without linking it to specialisation.
• Naming a change in cost per unit without saying that input prices are held constant.

Official syllabus

AQA AS and A-level Economics specification, version 1.3, 29 June 2022, published by AQA.