What is Economics?

Definition and Core Principles

Economics is the study of incentives and how these incentives influence people's choices. The discipline is built on three foundational principles:

• Optimization: Individuals strive to choose the best available option, given their information and constraints.

• Equilibrium: Economic systems tend to reach a state where no one can benefit by changing their own behavior, known as equilibrium.

• Empiricism: Economists use data and empirical analysis to test theories and understand real-world phenomena.

Key Terms

• Incentives: Factors that motivate individuals to act in certain ways.

• Optimize: To make the best possible choice given available information.

• Equilibrium: A situation where no agent has an incentive to change their behavior.

• Empiricism: The use of data and statistical analysis to inform economic understanding.

The Principles and Practice of Economics

Human Behavior and Choice

Economists study human behaviour, focusing on the choices individuals and groups make. The central theme is that choice—not money—is the unifying feature of all economic study. Economics applies to nearly every aspect of life, as choices are made in all domains.

Economic Agents

An economic agent is any individual or group that makes choices, such as consumers, firms, parents, or politicians. These agents interact within the economy, making decisions that affect themselves and society.

The Scope of Economics

Scarcity and Resource Allocation

Economics examines how agents make choices among scarce resources and how these choices impact society. Scarce resources are things people desire, but the quantity available is often less than the quantity wanted.

• Scarce resources: Goods or services for which demand exceeds supply.

Microeconomics vs. Macroeconomics

• Microeconomics: The study of incentives and choices facing individuals, firms, and governments.

• Macroeconomics: The study of the entire economy, including how monetary and fiscal policy affect microeconomic incentives and choices.

Normative and Positive Economics

Distinguishing Between Descriptive and Prescriptive Analysis

• Positive Economics: Describes and explains economic phenomena as they are. Example: "Some people took more than one candy and not everyone got a piece."

• Normative Economics: Prescribes what ought to happen based on value judgments. Example: "Each student should just take one so that everyone gets a piece."

Example: The Candy Bowl

• Positive question: How many pieces did each person take?

• Normative question: How many pieces should each person take?

Three Principles of Economics

Optimization, Equilibrium, and Empiricism

• Optimization: Making the best choice possible with given information.

• Equilibrium: When everyone is optimizing, and no one would be better off with a different choice.

• Empiricism: Using data to answer interesting questions and test economic theories.

The First Principle of Economics: Optimization, Trade-offs, and Budget Constraints

Optimization and Real-World Decision Making

Optimization involves making the best possible choice given available information. While individuals may not always succeed in optimizing due to limited information or cognitive limitations, they generally attempt to do so.

• Trade-offs: All optimization problems involve trade-offs, where some benefits must be sacrificed to gain others.

• Budget Constraint: The set of options a person can choose without exceeding their budget.

Opportunity Cost

Opportunity cost is the value of the best alternative forgone when a choice is made. It is a central concept in economics, guiding both individual and public policy decisions.

Example:

• The opportunity cost of attending university may be the income forgone from working during that time.

• The opportunity cost of buying a book for 10 (by driving 3 miles) is the time and cost of travel.

Cost-Benefit Analysis

Cost-benefit analysis weighs all opportunity costs and benefits to inform decision-making. Both individuals and policymakers should consider all opportunity costs, though these may sometimes be overlooked or exaggerated.

Summary Table: Positive vs. Normative Economics

Additional info:

• These notes provide foundational concepts for microeconomics, focusing on individual choice, resource allocation, and the distinction between descriptive and prescriptive economic analysis.