Principles of Microeconomics (Year 1): Markets, Choices and Policy

It is Saturday morning. You have a free day, some money in your account, and too many things you want to do: earn some cash, study for Monday’s test, see friends, sleep. You cannot do all of them. Whatever you pick, something else is left undone. That simple, everyday problem is the heart of economics.

Scarcity: the basic economic problem

Scarcity means that our wants are greater than the resources available to satisfy them. Resources include money, but also time, land, raw materials, machines and human effort. A billionaire still has only 24 hours in a day. A rich country still has a limited number of doctors.

Because of scarcity, every person, business and government must choose. This gives us a working definition:

Economics is the study of how people, firms and societies make choices when resources are scarce.

Notice that scarcity is not the same as poverty. Something is scarce whenever there is not enough of it to give everyone all they want at a price of zero. Clean water, seats in a popular university course and parking spaces in a city centre are all scarce, even in wealthy places.

Two ways to slice economics: micro and macro

Economists study choice at two levels.

• Microeconomics looks at individual decision-makers and single markets: a household deciding what to buy, a café deciding its prices, the market for rice or mobile data.
• Macroeconomics looks at the economy as a whole: total output (GDP), inflation, unemployment and economic growth.

This course is about microeconomics, but the two are linked: national unemployment is made up of millions of individual job decisions.

Two kinds of statements: positive and normative

Economists also separate what is from what should be.

• A positive statement describes how the world works. It can be checked against evidence, at least in principle. It may turn out to be wrong, but it is still positive.
• A normative statement says how the world ought to be. It depends on values and judgements, so evidence alone cannot settle it.

Examples:

• “Raising the tax on cigarettes reduces the number of cigarettes sold.” Positive: we can test it with data.
• “The government should raise the tax on cigarettes.” Normative: it depends on how we weigh health, freedom and fairness.
• “A higher minimum wage causes some low-skilled workers to lose their jobs.” Positive: economists disagree about the size of the effect, but the claim can be tested.
• “The minimum wage is too low.” Normative.

A quick test: look for words like should, ought, fair, too high or better. They usually signal a normative statement. Good economic analysis uses positive evidence to inform normative debates, while being honest about which part is which.

Opportunity cost: the real cost of a choice

If scarcity forces us to choose, every choice means giving something up. Economists call this the opportunity cost:

The opportunity cost of a choice is the value of the next best alternative you give up.

Two words matter here. Next best means we count only the single best option you passed over, not every option added together. You could only have done one thing with that time or money, so only one alternative is truly lost. Value means the cost is not always money; it can be time, enjoyment, a grade or rest.

Explicit and implicit costs

The full cost of a choice often has two parts:

• Explicit costs: money you actually pay, such as a ticket or tuition fees.
• Implicit costs: the value of what you give up with no money changing hands, such as wages you could have earned.

People tend to notice explicit costs and forget implicit ones. Economists insist on counting both.

Worked example: tutoring income or study time?

Rina is a first-year student. She has 4 free hours on Saturday afternoon. Her options (all numbers hypothetical):

1. Tutor a high-school student for 4 hours at $12 per hour.
2. Study for her statistics test on Monday.
3. Go to a concert with friends. The ticket costs $20 and the event takes the whole 4 hours.

Step 1: Find the money value of tutoring. 4 hours × $12 = $48.

Step 2: Suppose Rina decides to study. She ranks tutoring as her next best option. Her opportunity cost of studying is the $48 she could have earned. It is not $48 plus the concert, because she could never have done both in the same 4 hours.

Step 3: Suppose instead she goes to the concert, and tutoring is her next best option.

• Explicit cost: the $20 ticket.
• Implicit cost: the $48 of tutoring income she gives up.
• Full opportunity cost: $20 + $48 = $68.

Interpretation: the concert does not really cost Rina $20; it costs her $68 worth of resources. She should go only if she values the concert at more than $68. If she would happily pay, say, $80 for that experience, the concert is a good choice. If it is worth only $40 to her, she would be better off tutoring.

Step 4: A non-money cost. Suppose Rina’s next best alternative to tutoring is studying, and she believes 4 hours of study would raise her test score by about 10 marks. Then the opportunity cost of tutoring is those 10 marks (plus any tiredness or stress), even though no money is involved. Whether $48 is worth more than 10 marks is her judgement to make, but economics makes the trade-off visible.

Opportunity cost in everyday life

• Going to university. The cost is not just tuition and books. It includes the wages you could have earned working full time. This is why university is a bigger sacrifice for someone who already has a well-paid job offer.
• A “free” event. A free lecture or festival still costs the time you could have spent elsewhere.
• Government budgets. Money spent building a new highway is money not spent on hospitals or schools. Society faces opportunity costs just as individuals do.

Common misconceptions

• “Opportunity cost is the money I pay.” Correction: money paid is only the explicit part. Forgone time, income or enjoyment also count.
• “Opportunity cost is everything I could have done instead.” Correction: only the single next best alternative counts, because you could have chosen only one of them.
• “If something is free, it has no cost.” Correction: a zero price does not mean zero opportunity cost. Your time and attention are scarce.

Check your understanding

1. Is “Students should not have to pay for public transport” positive or normative? Answer: normative; it is a value judgement signalled by “should”.
2. A study of how rising petrol prices affect taxi fares in one city is micro or macro? Answer: micro; it looks at a single market.
3. Ali can work a 3-hour shift for $10 per hour or watch a film at home. He watches the film. What is his opportunity cost? Answer: $30 of forgone wages (3 × $10), assuming work was his next best alternative.

Key terms

• Scarcity: wants exceed the resources available to satisfy them.
• Economics: the study of choice under scarcity.
• Microeconomics: the study of individual decision-makers and markets.
• Macroeconomics: the study of the economy as a whole.
• Positive statement: a testable claim about how the world is.
• Normative statement: a value-based claim about how the world should be.
• Opportunity cost: the value of the next best alternative given up.
• Explicit cost: a direct money payment.
• Implicit cost: the value of a forgone alternative with no money payment.

Summary

• Scarcity means limited resources and unlimited wants, so choices are unavoidable.
• Microeconomics studies individuals and markets; macroeconomics studies the whole economy.
• Positive statements can be tested with evidence; normative statements rest on values.
• Opportunity cost is the value of the next best alternative, not the sum of all alternatives.
• Full cost = explicit costs + implicit costs; a choice is worthwhile only if its benefit exceeds that full cost.