IB Economics SLTopic 1 — Introduction to EconomicsPaper 1 & 2Core idea~10 min read
Scarcity, Choice and Opportunity Cost
There is not enough of anything to go round. That single sentence is why economics exists at all — if resources were unlimited, nobody would ever have to choose, and there would be nothing to study. Everything else in this course grows out of it.
📚 What you need to know
The basic economic problem is that resources are finite while human wants and needs are infinite.
Those resources are the factors of production: land, labour, capital and enterprise. Producing anything needs a combination of all four.
Each factor earns a factor income: rent for land, wages for labour, interest for capital, profit for enterprise.
Because resources are scarce, choices must be made — by consumers, producers, workers and governments.
Opportunity cost is the loss of the next best alternative when a choice is made. It is not a sum of money.
Economic goods are scarce and carry a price. Free goods are abundant, so nobody can profit from supplying them.
Every economy answers three questions — what, how and for whom — and the answers make it a market, mixed or planned system.
The basic economic problem
Economics is the study of scarcity and what it means for how resources get shared out in society. Put plainly: there are finite resources and infinite wants and needs.
Needs are essential to human life — food, shelter, clothing.
Wants are everything else — a bigger house, a newer phone, a yacht. There is no ceiling on them.
Because the two do not match, choices have to be made about the best and most efficient use of what exists. That applies to a household deciding what to buy and to a government deciding what to build.
The factors of production
The resources used to produce goods and services are called the factors of production. Producing any good or service needs a combination of all four.
Learn the four pairings in order. They come back in the circular flow of income, in national income accounting and in the macro papers.
In a free market economic system the factors of production are privately owned by households and firms. Households make their resources available to firms, firms buy land, labour and capital in factor markets, and households receive factor income in return.
What gets produced falls into two types. Goods are physical objects you can touch, such as a phone. Services are actions performed for someone else, such as a haircut or a car wash.
Factor
Producing a car needs
Income it earns
Land
Iron ore, rubber, oil, sand
Rent
Labour
Designers, production line staff, supply chain staff
Wages
Capital
Robotic arms, conveyor belts, computers, the factory itself
Interest
Enterprise
Whoever decided to build cars at all and carries the risk of it failing
Profit
Capital in economics does not mean money. It means man-made things used to produce other things — a machine, a delivery van, a factory. Money is how you buy capital; it is not capital itself. Students lose marks on this every single year.
Scarcity hits everyone
Scarcity is not only a problem for people with no money. Every group in an economy runs into it, and each responds differently.
Stakeholder
How scarcity shows up
Consumers
In a free market, scarcity feeds straight into prices. The scarcer something is relative to demand, the more consumers must pay for it.
Producers
Firms using scarce inputs face higher production costs than firms using abundant ones, which squeezes their margins or raises their prices.
Workers
Workers may want safer, more comfortable conditions, but their employer may not have the resources to provide them.
Governments
Governments must decide which goods and services to provide themselves and which to leave to private firms. That decision shapes how resources are allocated across the whole society.
Opportunity cost
Every choice closes off other choices. The best of the options you turned down is the opportunity cost.
Definition
opportunity cost = the loss of the next best alternative when a decision is made
Buy the phone and you cannot also buy the jeans. The jeans are the opportunity cost — assuming the jeans were what you would have bought instead.
Understanding opportunity cost changes decisions. Once a consumer, worker, firm or government factors in what they are giving up, they often choose differently — and a different choice means a different allocation of resources across the economy.
The single most common error on this topic: opportunity cost is not a monetary amount. Money is often involved, and you may well be asked to put a figure on it, but the concept itself is the loss of the next best alternative. Say “the loss of the next best alternative” in the definition, then do the arithmetic afterwards.
Economic goods and free goods
Economic goods are scarce relative to the demand for them, which is what makes them valuable. Because they have value, producers will supply them to make a profit. Anything with a price tag is an economic good: oil, corn, gold, trainers, bicycles.
Free goods are abundant in supply. There is so much of them that nobody can make a profit from supplying them — sunlight, the air we breathe, sea water.
The line between the two can move. Drinking water was a free good for most of human history. As populations grew and sources became polluted, clean water became scarce relative to demand — and so became an economic good.
Free goods have no opportunity cost. That is the real test, and it is a neater one than “does it have a price”. Using more sunlight does not stop anyone else using sunlight, so nothing is given up. As soon as your use of something denies it to someone else, it is scarce, and it is an economic good.
Economic systems and the three questions
Every society has to solve the same problem of scarcity, and the way it does so is its economic system. The agents involved include consumers, producers, the government and special interest groups such as trade unions or environmental campaigners. Whatever the system, its job is to allocate the scarce factors of production.
Nowhere runs a pure market or a pure planned system. Knowing that is more useful than memorising the three labels.
System
What to produce?
How to produce?
For whom?
Market
Whatever demand and supply signal, through the price mechanism
Whatever is most efficient and most profitable
Those who can afford it
Mixed
Demand and supply, with the government also making decisions
Efficiently, but with some weight given to welfare
Those who can afford it, plus provision for those who cannot
Planned
The government decides
In whatever way keeps everyone employed
Everyone
Worked examples
WORKED EXAMPLE
Maya is offered Job A paying 2,600 a month and Job B paying 2,300 a month. Job A means commuting 1 hour each way on 20 working days, with fares of 6 a day. She values her own time at 8 an hour. Which job leaves her better off? [4]
Step 1: work out the commuting time2 hours a day × 20 days = 40 hoursStep 2: value that time, and add the fares40 × 8 = 320 | fares = 6 × 20 = 120total cost of commuting = 320 + 120 = 440Step 3: compare the two jobs properlyJob A: 2600 − 440 = 2160Job B: 2300Job B leaves her 140 a month better offThe higher salary loses once the opportunity cost of her time is counted. Most people only count the fares.
WORKED EXAMPLE
Explain, using an example, why scarcity forces choices to be made. [4]
Define the problem
Resources, meaning the factors of production, are finite, while human wants and needs are infinite.
finite resources + infinite wants → not everything can be producedExplain the consequence
Because everything cannot be produced at once, decisions must be made about the most efficient use of what exists.
Give an example
A government with a fixed budget can build a new hospital or upgrade the rail network, but not both. Choosing the hospital means the rail upgrade is the opportunity cost.
Link back
Every such choice changes how resources are allocated across society, which is precisely what economics studies.
Finite resources, infinite wants, therefore choice, therefore opportunity cost
💡 Exam tip
Define opportunity cost as the next best alternative, never as “what it costs” or “the money you spend”.
Learn the four factor incomes as pairs. Land-rent, labour-wages, capital-interest, enterprise-profit. They reappear all through the macro unit.
Capital means machinery and equipment, not money. Say “man-made resources used to produce other goods”.
Use the no-opportunity-cost test to tell a free good from an economic good.
In calculation questions, include the value of time, not just the cash. That is usually where the marks are hiding.
Remember all four stakeholders — consumers, producers, workers, governments — when asked who scarcity affects.
⚠️ Common mix-up
Adding up everything you gave up. Opportunity cost is the single next best alternative, not the total of all rejected options.
Calling money a factor of production. Money buys factors; it is not one of them.
Thinking scarcity means poverty. A wealthy country still faces scarcity, because its resources are still finite relative to what it wants.
Assuming free goods are goods that cost nothing to buy. A free sample has a cost to somebody. A free good is abundant enough that nobody can profit from supplying it.
Confusing needs with wants. Needs are essential to life; everything beyond that is a want, however strongly it is felt.
Describing a real country as a pure market or pure planned economy. Every real economy is mixed to some degree.
Up next: The Production Possibilities Curve — scarcity, choice and opportunity cost all drawn on one diagram, and the first model you will be asked to sketch under exam conditions.
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