Learn: Economics 101: The Four Core Principles

Definition of Economics

The study of people in the ordinary business of life and a toolkit for making choices.

Microeconomics vs Macroeconomics

Microeconomics studies individual decisions, while macroeconomics traces broader implications across the whole economy.

The Cost-Benefit Principle

Evaluate the full set of costs and benefits; pursue a choice only if benefits are at least as large as costs.

Incentives Matter

The core conclusion of the cost-benefit principle stating that costs and benefits shape decisions.

Willingness to Pay

The most that an individual would be willing to pay to obtain a particular benefit or avoid a cost.

Economic Surplus

The difference between the total benefits you enjoy and the total costs you incur from a decision.

Voluntary Exchange

Transactions where both buyers and sellers benefit by earning an economic surplus.

Framing Effect

The phenomenon where small differences in how alternatives are described lead people to make different choices.

The Opportunity Cost Principle

The true cost of something is the next best alternative you must give up to get it.

Scarcity

The fundamental economic problem that resources like time, money, and attention are limited.

The 'Or What?' Trick

Asking 'or what?' to compare your primary choice against its next best alternative.

Sunk Costs

Time, effort, and money spent that cannot be reversed and should be ignored in decision-making.

Production Possibility Frontier (PPF)

A graph that maps out the different sets of output attainable with your scarce resources.

Effect of Productivity Gains on PPF

New techniques that allow doing more with the same inputs shift the production possibility frontier outward.

Either/Or Choices vs Quantity Choices

Either/or choices involve doing something or not, whereas quantity choices involve deciding 'how many'.

The Marginal Principle

Decisions about quantities are best made incrementally by breaking them down into smaller marginal choices.

Marginal Benefit

The extra benefit you get from one more unit of something.

Marginal Cost

The extra cost that comes with one more unit of something.

The Rational Rule

If something is worth doing, keep doing it until your marginal benefits equal your marginal costs.

Business Experimentation at the Margin

Testing incremental changes to discover marginal costs and benefits when exact values are unknown.

The Interdependence Principle

Your best choice depends on your other choices, others' choices, market developments, and future expectations.

Four Types of Interdependencies

Own choices, people in the same market, different markets, and dependencies through time.

MCOI Framework

The four-step process for solving economic problems: Marginal, Cost-benefit, Opportunity cost, Interdependence.

Someone Else's Shoes Technique

An empathetic technique used to understand and predict the decisions made by other economic actors.

The Four Core Questions

One more? (Marginal), Does benefit beat cost? (Cost-Benefit), Or what? (Opportunity Cost), What else? (Interdependence).

Nonfinancial Costs in Opportunity Cost

Costs that do not involve out-of-pocket money, such as time, effort, or forgone opportunities.

Comparative Advantage Analogy of Study Time

Treating oneself as a grades-producing factory whose inputs are study time and outputs are test scores.

Economic Profit

Total benefits less total costs, representing the surplus earned by a business.

Market Competition for Scarce Resources

Interactions where the more resources others get, the less are left over for you.

Interdependence Across Time

Choices today that expand or restrict your opportunities and trade-offs in the future.