Fundamental Economic Concepts
The Fundamental Economic Concepts domain tests the reasoning toolkit behind every later topic: scarcity and opportunity cost, marginal decision making, the production possibilities curve (PPC), comparative advantage, the circular flow, and the positive/normative distinction. Items usually ask you to apply the logic to a small scenario rather than recite a definition.
Core rules
- Scarcity forces choice. Opportunity cost is the value of the single best forgone alternative, not the sum of all alternatives, and it includes implicit costs.
- Marginal analysis compares marginal benefit with marginal cost; sunk costs are irrelevant to the decision.
- A bowed-out PPC reflects increasing opportunity cost because resources are imperfectly adaptable. Points inside are inefficient (unemployment); points outside are unattainable. Only growth in resources or technology shifts the curve outward.
- Comparative advantage means lower opportunity cost. Absolute advantage (fewer inputs per unit) does not determine the pattern of trade.
- The circular flow links households (supply factors, demand goods) and firms (demand factors, supply goods). Saving, taxes, and imports are leakages; investment, government spending, and exports are injections.
- Positive statements are testable; normative statements embed values. Ceteris paribus means holding other variables constant.
Worked example
Country A can produce 100 wheat or 50 cloth; Country B can produce 60 wheat or 60 cloth. Cloth costs A 2 wheat but costs B only 1 wheat, so B has comparative advantage in cloth and A in wheat. Any price between 1 and 2 wheat per cloth makes both better off: A buys cloth cheaply and sells wheat, while B specializes in cloth.
Traps
Confusing opportunity cost with money actually paid; calling a point inside the PPC unattainable; assuming the larger producer gains most from trade; labeling a policy statement positive merely because it cites data.