## Definition **Opportunity cost** is the value of the best alternative foregone when a choice is made. Because productive resources — time, capital, labour, land — are finite at any given moment, allocating them to one use necessarily means withholding them from every other use. The opportunity cost of a decision is not what was paid in money, but what was sacrificed in the next-best alternative. ## Core Mechanics Every economic agent, from an individual to a government, faces the same constraint: using a resource here means not using it there. Formally, if a resource $R$ can be allocated to use $A$ or use $B$, and $A$ is chosen, then the opportunity cost of $A$ is the value that $B$ would have produced. This applies at every scale: - **Individual:** An hour spent watching television costs the output that hour of work would have produced (or the rest that same hour of sleep would have provided). - **Firm:** Capital invested in a failing product line cannot simultaneously be invested in a growing one. - **Government:** Tax revenue spent on subsidising industry $X$ is revenue not available to reduce taxes or fund alternative public goods. The seen expenditure always has an unseen alternative. ## Role in Policy Analysis Opportunity cost is the analytical engine behind [[The One Lesson (Seen and Unseen)]]. Hazlitt notes that economic fallacies consistently arise from counting only the expenditure that *did* happen (the seen) and ignoring the expenditure that *did not* happen because the resources were redirected (the unseen). Applied examples from Hazlitt: - **Tariffs:** Protecting a domestic industry forces consumers to pay a higher price, the difference being the opportunity cost: goods and services those consumers cannot now buy with the overpaid amount. - **Public works:** Every job created by a government infrastructure programme has an opportunity cost in the private-sector jobs and investment displaced by the taxation that financed it. - **Minimum wages:** The employer who must pay a higher wage has less capital available to hire additional workers or invest in productivity improvements. ## Distinction from Accounting Cost Accounting cost records cash outflows. Opportunity cost records forgone value, which may be zero in monetary terms yet economically decisive. A government that prints money to finance spending incurs zero accounting cost but a substantial opportunity cost (the purchasing power lost by existing money holders). ## Epistemic Note Opportunity cost is accepted across all mainstream economic schools — it is a logical consequence of scarcity, not a contested proposition. Where schools diverge is in *measuring* the opportunity cost of specific policies, particularly whether idle resources (in a recession) reduce opportunity costs materially. ## Related - [[The One Lesson (Seen and Unseen)]] - [[The Broken Window Fallacy]] - [[Effects of Price Controls]] - [[The Fallacy of Make-Work and Saved Jobs]] ## Sources - [[Economics in One Lesson (Hazlitt 1946)]]