IB Economics HLTopic 1 — Introduction to EconomicsPaper 1 & 2Core idea~9 min read
Scarcity, Choice and Opportunity Cost
Everything in this course grows out of one stubborn fact: there is not enough stuff to go round. Not enough land, not enough workers, not enough hours, not enough money. Because of that, somebody always has to choose — and every choice quietly throws something else away. That thrown-away option has a name, and examiners love it.
📚 What you need to know
The basic economic problem: wants are unlimited, resources are limited.
Resources are called the factors of production: land, labour, capital and enterprise.
Each factor earns its own income: rent, wages, interest and profit.
Because resources are scarce, choices must be made by consumers, firms, workers and governments.
Opportunity cost is the value of the next best alternative given up — not everything given up.
Economic goods are scarce and have a price. Free goods are so abundant that they have no opportunity cost.
Scarcity is not the same as poverty. Rich countries face it too.
The basic economic problem
Write down everything you would buy if money were no object. Now keep writing. You will not run out of ideas — that is the point. Human wants are effectively unlimited. Meet one and another appears behind it.
Now list what the world actually has to work with: a fixed amount of land, a fixed number of workers, a fixed stock of machines and factories. Those are finite. The gap between the two lists is what economists call scarcity, and it never closes.
Notice the two boxes are drawn to different sizes on purpose. If they were the same size there would be no economics to study.
Needs and wants are different. A need keeps you alive: food, water, shelter, basic clothing. A want is everything beyond that. Economics is mostly about wants, because needs are usually met long before the wanting stops.
The four factors of production
When economists say “resources”, they mean four specific things. Learn all four and, just as importantly, learn what each one earns.
The bottom row is the bit students forget. Land earns rent, labour earns wages, capital earns interest and enterprise earns profit.
Two traps here. Capital in economics means physical equipment, not money in a bank — money buys capital, it is not capital itself. And land includes everything nature provides, so fish stocks and oil reserves count as land, not capital.
Opportunity cost
Scarcity forces a choice. Choosing one thing means not choosing another. The value of the next best option you turned down is the opportunity cost.
Definition
Opportunity cost = the value of the next best alternative forgone
The words “next best” do a lot of work. If you have $500 and you could spend it on a laptop, a bike or a holiday, and you buy the laptop, the opportunity cost is only the bike (assuming that was your second choice). It is not the bike plus the holiday. You only ever gave up one alternative, because you could only ever have taken one.
Opportunity cost is not a price. It is whatever you lost by choosing — which is often time, freedom or a different life, not money.
Everyone faces it, not just shoppers
Who is choosing
The choice
The opportunity cost
A consumer
Spend $500 on a laptop
The bike they would otherwise have bought
A worker
Take the higher-paid job further away
The extra free time the closer job offered
A firm
Use a factory to make vans
The cars that factory could have made
A government
Build a new hospital
The schools that budget could have funded
The government row is the one that scores marks in essays. Every time you write “the government should spend more on X”, add the sentence “but this carries an opportunity cost, since the same funds could have gone to Y”. That single sentence is often the difference between a level 2 and a level 3 evaluation.
Economic goods and free goods
An economic good is scarce relative to the demand for it. Because it is scarce, it has a price, and producing more of it uses up resources that could have made something else. Almost everything you can think of sits here: phones, coffee, haircuts, flights.
A free good is so abundant that using it costs nobody anything. Sunlight is the classic example. Nobody has less sunlight because you sat in the sun. There is no opportunity cost, so there is no price and no market.
The list is shrinking. Clean air and clean drinking water were once free goods. In many places they now have to be filtered, treated and paid for — so they have turned into economic goods. Scarcity is not fixed forever; it can be created.
Worked examples
WORKED EXAMPLE 1
Maya can work a shift for $90, revise for an exam, or visit her cousin. She ranks them: revising first, working second, visiting third. She chooses to revise. State her opportunity cost. [2]
Step 1: identify the chosen option
She revises.
Step 2: find the NEXT BEST rejected option
Her ranking puts working second, so that is the next best.
Opportunity cost = the $90 shiftThe visit is third, so it is not the opportunity cost. Only one alternative ever counts.
WORKED EXAMPLE 2
A council has $4 million. Option A: a library that will serve 12 000 people. Option B: a sports centre for 9 000 people. Option C: resurface roads used by 20 000 people. It picks the roads. Explain the opportunity cost. [3]
Step 1: rank the rejected options
Rejected: library (12 000 users) and sports centre (9 000 users).
Step 2: pick the better rejected one12 000 > 9 000, so the library is the next best alternative.
Step 3: state it as a loss of benefit
The opportunity cost is the benefit 12 000 people would have gained from the library.
The library, not the library plus the sports centreSay what is lost in terms of benefit to people, not just “$4 million”. The money was always going to be spent.
WORKED EXAMPLE 3
Classify each as land, labour, capital or enterprise: (a) a delivery van; (b) an underground copper deposit; (c) a nurse; (d) the founder who risks her savings to open a bakery. [4]
Ask: is it made by people, given by nature, human effort, or risk?
(a) Man-made, used to produce a service → capital
(b) Provided by nature → land
(c) Human effort in production → labour
(d) Takes the risk and combines the other factors → enterprisecapital, land, labour, enterpriseHer savings are money, not capital. The oven she buys with them is capital.
💡 Exam tip
Say “next best alternative forgone” word for word. Mark schemes look for it.
Give a number when the question gives you one. “$90” scores; “the money she could have earned” is vaguer.
Express opportunity cost as lost benefit, not lost cash, whenever people are involved.
Use opportunity cost as your default evaluation tool. Any policy that spends money has one.
Learn the reward for each factor. One-mark questions on rent, wages, interest and profit come up often.
Remember free goods have no opportunity cost. That is the definition, not “things that cost nothing”.
⚠ Common mix-up
Adding up every rejected option. Opportunity cost is one thing: the next best.
Confusing scarcity with shortage. A shortage is temporary and can be fixed. Scarcity is permanent.
Calling money capital. Capital is physical: machines, tools, buildings, vehicles.
Thinking free goods are goods with a price of zero. A free sample is still an economic good — someone used resources to make it.
Assuming opportunity cost only applies to money. Time is the most commonly forgotten one.
Saying rich countries have solved scarcity. They face it too; their choices are just between different things.
Listing needs as wants. Shelter is a need; a second home is a want.
Up next: The Production Possibilities Curve — the diagram that puts scarcity, choice and opportunity cost on one set of axes.
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