Pearson Edexcel International GCSE Economics: Scarcity, the PPF and assumptions (4EC1)

This guide covers sections 1.1.1 (The economic problem) and 1.1.2 (Economic assumptions) of the Pearson Edexcel International GCSE Economics (4EC1) specification, Issue 3, February 2026. It is a single-tier qualification, so everything here is for every candidate. The content sits in Paper 1: Microeconomics and Business Economics, and the specification says topics can be interrelated. All figures below are invented and illustrative.

Related pages: revision notes, practice questions, the wider market system guide, the course hub, the checklist and the free diagnostics.

Outcomes covered

Section	Outcome
1.1.1 a	Explain scarcity: unlimited wants, finite resources, so choices must be made
1.1.1 b	Explain opportunity cost and its effect on consumers, producers and government
1.1.1 c-d	Use a production possibility curve to show maximum productive potential, employed and unemployed resources, opportunity cost, growth and decline, possible and unobtainable output
1.1.1 e	Give possible causes of positive or negative economic growth
1.1.2 a	State the assumptions that consumers maximise benefit and businesses maximise profit
1.1.2 b	Explain why consumers may not maximise benefit
1.1.2 c	Explain why producers may not maximise profit

Scarcity and choice (1.1.1 a)

Wants are unlimited: people always want more or better goods and services. Resources are finite: land, labour, capital and enterprise exist in limited amounts. Scarcity is the gap between the two. Because not every want can be met, someone has to choose what to produce, how and for whom.

Scarcity is not the same as poverty or shortage. A rich country faces scarcity too, because its wants also outrun its resources. A shortage is a market problem at one price, while scarcity is the permanent economic problem.

Opportunity cost (1.1.1 b)

Opportunity cost is the value of the second-best option that is sacrificed once you choose. It is that one option, not the total of everything you could have done. You can measure it in goods, time or money.

Consumer. Sam has 40 units of spending money. Sam ranks the options as a water park day pass (40), a tennis racket (40) and four paperbacks (10 each). Sam buys the day pass. The opportunity cost is the racket, not the racket plus the paperbacks. A different ranking would change the opportunity cost, even though the price paid is the same.

Producer. A small bakery has 6,000 units to invest. A new oven would add 900 a year to profit, a delivery van 700 and advertising 500. The bakery chooses the oven. The opportunity cost is the van’s 700 a year. As rates of return, the oven earns 900 ÷ 6,000 × 100 = 15% a year and the van 700 ÷ 6,000 × 100 = 11.7%. Checking opportunity cost helps firms see whether a choice is worth it.

Government. The government of Country A has 240 million units. It can build one hospital wing (240 million), four primary schools (60 million each) or a 30 km road (8 million per km). Check the arithmetic: 4 × 60 = 240 and 30 × 8 = 240, so each option uses the whole budget. If it builds the wing, the schools are the next best option and become the opportunity cost. Taxpayers may judge that choice by what they lose as well as what they get.

The production possibility frontier (1.1.1 c-d)

A production possibility curve (the PPF, or frontier) shows every combination of two goods that an economy can produce at most in a period, with all resources in use and technology fixed. Country A makes machines and food. Output is in thousands of units.

Point	Machines	Food
A	0	100
B	10	94
C	20	82
D	30	60
E	40	0

Drawing it. Put machines on the horizontal axis and food on the vertical axis. Plot A to E and join them with a smooth curve that bows outwards from the origin. Label both axes and the curve. Where the curve meets each axis, the economy puts all resources into one good.

Food
100 |A
 94 | B
 82 |   C
 60 |      D
    |         .
  0 +----------E--- Machines
    0 10 20 30 40

Maximum productive potential. Every point on the curve is the most the economy can produce. Resources are fully employed and none is wasted.

Opportunity cost. Moving along the curve, more of one good means less of the other.

• A to B: 10 more machines cost 100 − 94 = 6 food, so 0.6 food per machine.
• B to C: 94 − 82 = 12 food, so 1.2 per machine.
• C to D: 82 − 60 = 22 food, so 2.2 per machine.
• D to E: 60 food, so 6 per machine.

The opportunity cost rises because resources are not equally good at making both goods. Fertile land suits food, and skilled engineers suit machines. The curve bows outwards for this reason. A straight-line PPF would mean a constant opportunity cost.

Inside, on and outside. Point F is 20 machines and 70 food. It lies inside the curve, so resources are unemployed or not used fully. The economy could produce 82 − 70 = 12 more food with no loss of machines. That is 12 ÷ 82 × 100 = 14.6% below its potential. Point G is 30 machines and 80 food. It lies outside the curve and is unobtainable with present resources, because the frontier at 30 machines is only 60 food. Points on the curve are possible and efficient, points inside are possible but wasteful, and points outside are unobtainable.

Growth and decline. Economic growth shifts the whole curve outwards. If every maximum rises by 20%, food rises to 100 × 1.2 = 120 and machines to 40 × 1.2 = 48. Point C (20, 82) moves to (24, 98.4) and D (30, 60) moves to (36, 72). At 30 machines the new curve sits at least as high as the straight line between those two, which is 85.2 food, so G (80 food) is now obtainable. Negative growth shifts the curve inwards. If a conflict destroys 25% of capacity, food falls to 75 and machines to 30.

Growth can be uneven. If only farming technology improves, the food intercept rises from 100 to 125, a rise of 25%, while the machines intercept stays at 40. The curve pivots outwards on one axis only.

Moving versus shifting. Moving from C to D along the curve is a change in the mix, caused by a choice. Moving from F to the curve is the use of idle resources, not growth. Only a change in the economy’s ability to produce shifts the curve.

Causes of growth and decline (1.1.1 e)

Positive growth (outward shift)	Negative growth (inward shift)
More resources: new mineral finds, more workers through migration or higher participation	Loss of resources: depleted fields or mines, workers leaving the country
Better quality: education and training raise skills	Skills lost or unused: a worse-educated workforce, long-term illness
Investment in capital goods such as machinery and roads	Capital destroyed or left to wear out: war, flood, earthquake
Better technology and methods	Technology lost or access cut off by sanctions or conflict

State a cause, then say how it changes the quantity or quality of resources, and then link it to the curve. For example: investment in machines raises the amount of capital, so more of both goods can be produced, and the curve shifts outwards.

Economic assumptions (1.1.2)

Economists build simple models by assuming that consumers aim to maximise their benefit and businesses aim to maximise their profit. The assumptions make predictions possible, such as buying more of a good when its price falls. Real people and firms do not always behave that way.

Why consumers may not maximise benefit (1.1.2 b)

• Poor calculation. Consumers do not always compare benefit and cost well. A shop sells a 500 g pack of rice for 4 units and a 2 kg pack for 17. The large pack looks like a bargain, but 17 ÷ 4 = 4.25 per 500 g, which is dearer than the small pack. A buyer who assumes bigger means cheaper and does not check the unit price gets less benefit than they expected.
• Habits. A buyer who spends 3.50 on a coffee each working day spends 3.50 × 5 × 52 = 910 units in a year. A cheaper drink or home-made coffee might give nearly the same benefit, but the habit is hard to give up.
• Copying others. Choices follow friends, social media or fashion rather than personal benefit. A buyer may buy a brand because classmates do and later regret it.

Why producers may not maximise profit (1.1.2 c)

• Revenue or sales maximising managers. Managers may want growth, pay or prestige, so they aim for the highest sales rather than the highest profit. The workshop below shows the effect.
• Caring for customers. A firm might keep a free repair service or charge fair prices, which lowers short-term profit but builds loyalty.
• Charitable work. A bakery gives away 30 loaves a day that it could have sold at 3 each. Revenue forgone is 30 × 3 = 90, the baking cost is 30 × 1.5 = 45, so it gives up 90 − 45 = 45 profit a day, or 270 over a six-day week.

Workshop example. A workshop faces price = 60 − 2 × output and total cost = 100 + 20 × output. Revenue is price × output and profit is revenue minus cost.

Output	Price	Revenue	Cost	Profit
5	50	250	200	50
8	44	352	260	92
10	40	400	300	100
12	36	432	340	92
15	30	450	400	50
17	26	442	440	2
18	24	432	460	−28

Profit is greatest at 10 units (100). Revenue is greatest at 15 units (450), where profit has fallen to 50. A revenue-maximising manager picks 15 units and gives up 100 − 50 = 50 profit compared with the profit-maximising choice. A sales-maximising manager who wants the highest output without making a loss picks 17 units, where profit is only 2, so 100 − 2 = 98 of profit is given up.

Evaluating the assumptions

The assumptions are useful when you need a clear prediction, and they are often a fair guide for firms in tough competition, where survival needs profit. They are weaker when a firm is owner-managed, when it is a social enterprise or when buyers act quickly on impulse. A balanced judgement says when each assumption holds and why.

Common errors

• Writing “opportunity cost is the cost of the other options”. It is the single next best option.
• Calling a point inside the PPF “unobtainable”. It is possible but wasteful.
• Showing growth as a movement along the curve rather than a shift.
• Drawing a PPF with unlabelled axes or a curve that touches neither axis.
• Treating scarcity as a lack of money.
• Saying all firms always maximise profit.

Official syllabus

Pearson Edexcel International GCSE in Economics (4EC1) specification, Issue 3, February 2026, for first teaching September 2017, published by Pearson Education Limited, sections 1.1.1 and 1.1.2.