Scarcity, choice, and markets
Economics begins with a simple fact: we want more than we can have. Every choice therefore has a cost, and markets are one way societies decide who gets what.
Scarcity
Scarcity means resources (time, money, land, labour, raw materials) are limited while wants are not. Because of scarcity, individuals, firms, and governments must choose. Economics studies how those choices are made and what follows from them. Microeconomics focuses on individual households, firms, and markets; macroeconomics on the economy as a whole.
Opportunity cost
The opportunity cost of a choice is the value of the next best alternative you give up. If you spend an evening studying instead of working a shift that pays 60 dollars, the opportunity cost of studying includes that 60 dollars. Good decisions weigh opportunity costs, not just money spent.
Thinking at the margin
Most decisions are about a little more or a little less, not all or nothing. Economists compare marginal benefit (the extra benefit of one more unit) with marginal cost (the extra cost). It is worth doing more of something as long as the marginal benefit exceeds the marginal cost.
The production possibilities frontier
A production possibilities frontier (PPF) shows the combinations of two goods an economy can produce with its resources and technology. Points on the curve are efficient; points inside are wasteful; points outside are unreachable for now. Moving along the curve shows the opportunity cost of one good in terms of the other. Growth in resources or technology shifts the curve outward.
Markets and prices
A market is any arrangement that brings buyers and sellers together, from a farmers' market to online stock trading. Prices act as signals: a rising price tells producers to make more and consumers to economise, coordinating millions of decisions without a central planner.
Positive and normative economics
Positive statements describe how the world is and can be tested: 'a higher minimum wage reduces teenage employment'. Normative statements say how the world should be and involve values: 'the minimum wage should be raised'. Economists disagree on both, but separating them clarifies debates.
Models and assumptions
Economists use simplified models, like maps, to focus on key relationships. A common assumption is ceteris paribus, 'other things equal': change one factor while holding the rest constant. Models are judged by how well they predict, not by whether every assumption is literally true.
Worked example
A farmer can grow 100 tonnes of wheat or 50 tonnes of corn on her land, or combinations in between along a straight-line PPF. Each tonne of corn costs 2 tonnes of wheat. If she grows 20 tonnes of corn, she can grow 100 - 2 x 20 = 60 tonnes of wheat.
Key takeaways
Scarcity forces choices; the opportunity cost of a choice is the best alternative given up. Rational decisions compare marginal benefits and costs. The PPF shows efficient combinations and trade-offs. Market prices coordinate decisions. Positive statements are testable; normative ones involve values. Models simplify using ceteris paribus.
Flashcard
Limited resources, unlimited wants
Check your understanding
A student skips a 50-dollar concert to study. What is the opportunity cost of studying?