Notes on Economics: Foundations, Methodology, and Incentives
The Foundations: What is Economics
Different ways to define economics:
Jacob Vinaire (University of Chicago, 1920s): “economics is what economists do.” Frank Knight chimed in: “economists are those who do economics.” Not particularly helpful as a definition.
Adam Smith’s perspective (from The Wealth of Nations): economics studies the advantages of division of labor (trade) not as a product of foreseen wisdom, but as a slow, gradual consequence of a human propensity to truck, barter, and exchange one thing for another. In Smith’s view, economics focuses on this propensity and the patterns of exchange, both formal (money-for-goods) and informal (favors and reciprocal help).
Core focus of the course: how people behave in market relationships, with emphasis on incentives, structures of exchange (formal and informal), and the role of social norms, law, and institutions.
Money is important but not the sole subject: economics is about people, their relationships, and their behavior; macroeconomics will spend more time on money, but economics as a discipline studies more than money itself.
Methodological stance: methodological individualism
Definition: study market behavior by looking at individuals and their interactions, not large-scale societal forces in isolation.
Institutions and aggregate outcomes emerge from interactions of individuals, not from some monolithic “society” acting as a unit.
Examples: Congress is 535 individuals acting in interaction; markets produce prices through buyer–seller interactions.
Relationship to other disciplines:
Psychology matters (behavioral economics), but this course emphasizes the economic way of thinking focusing on individual behavior.
Economics can be used to analyze topics beyond traditional markets (public choice theory, law, war, etc.).
Real-world relevance includes applications even in fictional settings (e.g., game economies in Dungeons & Dragons).
A definitional anchor (textbook-style): economics is a study of how individuals and societies allocate their limited resources to satisfy practically unlimited wants. The course adds emphasis on exchange and choice, the rules and incentives that govern behavior, and the evolution of institutions.
The Methodological Core: Methodological Individualism and Assumptions
Methodological individualism as a research method:
Look at individuals interacting in markets to understand how outcomes arise.
Institutions (like Congress or markets) are the result of many individual actions and interactions, not the vice versa.
Agents and rationality:
Assumptions about humans:
Self-interest: people act to improve their own position, relieve pain, gain satisfaction, or help others if it serves a goal.
Rationality (not perfect): given information, people attempt to choose the best available option; mistakes happen due to bounded knowledge and constraints.
Users should think in terms of the constraints that shape decisions (time, budget, information, etc.).
Boundaries of the model:
We use simplifying assumptions to gain insights; these assumptions need not be true in every case for the model to be useful (parallels with physics: e.g., ignoring wind resistance to see core forces).
Value judgments about costs and benefits are subjective, not objective: the worth of goods depends on the person and context (e.g., a bottle of water is worth more in the desert than in a temperate climate).
Individuals vs. institutions:
Institutions are analyzed as collections of individual actions and constraints; e.g., Congress does not “do” something on its own, but the actions of 535 people lead to outcomes.
Prices emerge from interactions, not from a central decree.
Scope beyond markets:
The methodological approach applies to topics like voting, law, and war, illustrating the broad applicability of analyzing choices and incentives.
Behavioral economics note:
Psychology can inform economic analysis, but this course emphasizes standard economic analysis of behavior, while acknowledging that behavioral insights can enrich understanding.
Core Assumptions About Humans in Economic Reasoning
People act to move toward a better position: self-interest drives actions aimed at improving circumstances, reducing pain, or creating gains.
Rationality (bounded): individuals are rational in the sense that given information and constraints, they attempt to maximize perceived benefits; not perfect knowledge or omniscience.
Constraints shape choices: time, money, information, and other resources bound decisions.
Subjective evaluation of costs and benefits: value is not intrinsic to the object but varies by person and context.
No gods or kings; focus on people: economics analyzes decisions made by real humans under real constraints, not abstract collective entities.
Implications:
These assumptions help explain why people sometimes act in seemingly inconsistent ways when viewed without the constraint of individual motives and information.
They also pave the way to explain paradoxes in policy and institutional design (e.g., why certain policies persist even when they make many individuals worse off).
Money, Markets, and the Scope of Analysis
Money is important but not the central subject:
The economy is about how people exchange and interact, not merely about dollar values.
Money serves as a medium of exchange, a unit of account, and a store of value; however, the analysis foregrounds exchange relationships beyond just monetary transactions.
Institutions as aggregates of individuals:
Market prices emerge from the interactions of buyers and sellers, not from authorities alone.
The same methodological lens can be applied to various institutions (e.g., legal systems, voting regimes) to understand outcomes.
Five Big Ideas (compressed from ten) that Shape Economic Thinking
1) Incentives matter
Incentives can be positive (rewards) or negative (punishments).
Real-world examples:
Course incentives: doing well can yield an A, scholarships, etc.; disincentives can include penalties for cheating.
COBRA problem (historical): British India bounty on cobras led to breeding cobras and selling eggs—perverse incentive example showing incentives can backfire.
Australian convict transport: pay-per-prisoner-delivered-alive shifted behavior to reduce deaths; improved survival rates.
Core takeaway: incentives shape behavior; they do not always work as intended due to unintended consequences and information gaps.
2) Trade-offs are everywhere (scarcity and choice)
We live in a world of scarcity; every action involves giving up something else (even if costs are non-monetary).
Example: choosing to watch this video means giving up other activities (e.g., Facebook, multitasking, etc.).
Implication: there is always a trade-off even when costs are not explicit.
3) Opportunity costs (the true cost of any choice)
Defined as the highest-valued alternative sacrificed to take an action.
Example from the lecture:
Decision: stay in a current job as a consultant vs. going to grad school.
Monetary tuition for PhD is often zero (funding covers tuition), so the real cost is the foregone salary from the job: about $ ext{ extdollar}100{,}000$ per year for six years, roughly $ ext{ extdollar}600{,}000$ total.
Formal expression: the opportunity cost of action A is the value of the best foregone alternative.
4) Marginal thinking (think at the margin)
Most decisions are not all-or-nothing; they involve small changes (one more unit of something).
Decision rule (standard): compare marginal benefits and marginal costs.
Formal intuition:
Let MB be marginal benefit and MC be marginal cost of the next unit; act if , or more precisely if the net marginal benefit is positive:
ext{Net Benefit}{ ext{marginal}} = MB{ ext{marginal}} - MC_{ ext{marginal}} > 0.
5) Trade creates value (voluntary exchange and mutual benefit)
When parties trade, each is typically made better off because value is subjective and people transfer goods they value less for goods they value more.
Intuition with a water bottle example:
Buyer (you) values water at more than the price paid; seller (Aldi) values the money more than holding the water.
The result: both parties gain; trade expands total value in society when voluntary.
Important caveat: restrictions on trade reduce total value by impeding voluntary exchanges.
Interconnections among the five ideas:
Incentives influence trade-offs and marginal decisions, which in turn shape trade patterns and the creation (or destruction) of value.
The same framework helps explain economic phenomena beyond markets, such as public policy choices (tariffs, regulation) and institutional outcomes.
Concrete Incentives and Market-Structure Examples
The Cobra bounty (19th century India):
Government paid for every dead cobra; unintended consequence was breeding cobras and selling the dead bodies for the bounty.
Lesson: incentives can misalign with intended policy goals; design features matter for the intended behavior.
The Australian convict transport incentive reform:
First policy: pay captains per prisoner loaded in London.
Result: high death rate and poor treatment; a later reform paid per prisoner delivered alive to Australia.
Result: sharply reduced deaths; almost all prisoners survived the voyage.
Tariffs under the 2018 policy (Trump administration):
Net cost to the country estimated at about over the period considered.
Per capita impact: roughly dollars per day, or about per year per person.
The tariff benefits concentrated in a small group (steelworkers) and the costs dispersed across everyone else due to higher prices and reduced consumption.
Why policies persist: highly concentrated benefits for a lobbying group can outweigh dispersed costs that individuals face, leading to policies that make the average person worse off but benefit a focused minority.
Implication for methodological individualism:
When analyzing policy outcomes, consider the incentives faced by individual actors (voters, firms, workers) rather than assuming a single national will.
This framework helps explain why seemingly irrational policies persist in democracies.
Economics Beyond Markets: Applications of Methodological Individualism
Public choice economics: how politicians, voters, and bureaucrats make decisions; the incentives at the individual level help explain collective outcomes.
Law and judges: how individual beliefs, incentives, and information affect legal decisions and the law’s evolution.
War and international relations: why nations undertake certain actions; the drivers of conflict can be analyzed through individual incentives and strategic interactions.
Fictional/game economies: real economic thinking can be applied to balance in-game economies (e.g., Dungeons & Dragons) to understand resource distribution and player incentives.
The Economic Way of Thinking: What Economics Tries to Explain
Economics as the study of exchange and choice:
How people think about actions, how they weigh costs and benefits, and how those calculations lead to patterns of trade and cooperation.
The aim is to understand not only what actions are taken but why they are taken given incentives and constraints.
The role of rules, institutions, and norms:
Social rules (justice, benevolence, reciprocity) shape incentives and thereby influence market outcomes.
Practical takeaway for students:
Learn to identify incentives, trade-offs, and marginal decisions in everyday life and public policy.
Use the economic way of thinking to interpret behavior beyond the market: voting, law, war, and even fictional economies.
Summary: How the Big Ideas Fit Together
The core toolkit rests on five big ideas (with an eye toward tied concepts like opportunity cost and marginal analysis):
Incentives matter
Trade-offs are everywhere
Opportunity costs are the true costs of choices
Marginal thinking guides most decisions
Trade creates value through voluntary exchange
These ideas are interconnected; changing incentives alters trade-offs, marginal decisions, and the value created through trade, which can in turn affect broader institutional outcomes.
The methodological individualist lens helps explain why policies can have unintentionally bad outcomes or persist despite making many people worse off, by focusing on the incentives faced by individual actors rather than broad aggregates.
Final Takeaways
Economics studies how people behave in exchange relationships, using simplifying assumptions to reveal core mechanisms.
Money matters, but the subject is the broader set of market relationships and the incentives that drive behavior.
A disciplined way of thinking (incentives, opportunity costs, marginal analysis, and trade) provides powerful tools for understanding everyday life and public policy.