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Principles of Economics 2e

1.3 How Economists Use Theories and Models to Understand Economic Issues

Principles of Economics 2e1.3 How Economists Use Theories and Models to Understand Economic Issues
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  1. Preface
  2. 1 Welcome to Economics!
    1. Introduction
    2. 1.1 What Is Economics, and Why Is It Important?
    3. 1.2 Microeconomics and Macroeconomics
    4. 1.3 How Economists Use Theories and Models to Understand Economic Issues
    5. 1.4 How To Organize Economies: An Overview of Economic Systems
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
  3. 2 Choice in a World of Scarcity
    1. Introduction to Choice in a World of Scarcity
    2. 2.1 How Individuals Make Choices Based on Their Budget Constraint
    3. 2.2 The Production Possibilities Frontier and Social Choices
    4. 2.3 Confronting Objections to the Economic Approach
    5. Key Terms
    6. Key Concepts and Summary
    7. Self-Check Questions
    8. Review Questions
    9. Critical Thinking Questions
    10. Problems
  4. 3 Demand and Supply
    1. Introduction to Demand and Supply
    2. 3.1 Demand, Supply, and Equilibrium in Markets for Goods and Services
    3. 3.2 Shifts in Demand and Supply for Goods and Services
    4. 3.3 Changes in Equilibrium Price and Quantity: The Four-Step Process
    5. 3.4 Price Ceilings and Price Floors
    6. 3.5 Demand, Supply, and Efficiency
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  5. 4 Labor and Financial Markets
    1. Introduction to Labor and Financial Markets
    2. 4.1 Demand and Supply at Work in Labor Markets
    3. 4.2 Demand and Supply in Financial Markets
    4. 4.3 The Market System as an Efficient Mechanism for Information
    5. Key Terms
    6. Key Concepts and Summary
    7. Self-Check Questions
    8. Review Questions
    9. Critical Thinking Questions
    10. Problems
  6. 5 Elasticity
    1. Introduction to Elasticity
    2. 5.1 Price Elasticity of Demand and Price Elasticity of Supply
    3. 5.2 Polar Cases of Elasticity and Constant Elasticity
    4. 5.3 Elasticity and Pricing
    5. 5.4 Elasticity in Areas Other Than Price
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  7. 6 Consumer Choices
    1. Introduction to Consumer Choices
    2. 6.1 Consumption Choices
    3. 6.2 How Changes in Income and Prices Affect Consumption Choices
    4. 6.3 Behavioral Economics: An Alternative Framework for Consumer Choice
    5. Key Terms
    6. Key Concepts and Summary
    7. Self-Check Questions
    8. Review Questions
    9. Critical Thinking Questions
    10. Problems
  8. 7 Production, Costs, and Industry Structure
    1. Introduction to Production, Costs, and Industry Structure
    2. 7.1 Explicit and Implicit Costs, and Accounting and Economic Profit
    3. 7.2 Production in the Short Run
    4. 7.3 Costs in the Short Run
    5. 7.4 Production in the Long Run
    6. 7.5 Costs in the Long Run
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  9. 8 Perfect Competition
    1. Introduction to Perfect Competition
    2. 8.1 Perfect Competition and Why It Matters
    3. 8.2 How Perfectly Competitive Firms Make Output Decisions
    4. 8.3 Entry and Exit Decisions in the Long Run
    5. 8.4 Efficiency in Perfectly Competitive Markets
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  10. 9 Monopoly
    1. Introduction to a Monopoly
    2. 9.1 How Monopolies Form: Barriers to Entry
    3. 9.2 How a Profit-Maximizing Monopoly Chooses Output and Price
    4. Key Terms
    5. Key Concepts and Summary
    6. Self-Check Questions
    7. Review Questions
    8. Critical Thinking Questions
    9. Problems
  11. 10 Monopolistic Competition and Oligopoly
    1. Introduction to Monopolistic Competition and Oligopoly
    2. 10.1 Monopolistic Competition
    3. 10.2 Oligopoly
    4. Key Terms
    5. Key Concepts and Summary
    6. Self-Check Questions
    7. Review Questions
    8. Critical Thinking Questions
    9. Problems
  12. 11 Monopoly and Antitrust Policy
    1. Introduction to Monopoly and Antitrust Policy
    2. 11.1 Corporate Mergers
    3. 11.2 Regulating Anticompetitive Behavior
    4. 11.3 Regulating Natural Monopolies
    5. 11.4 The Great Deregulation Experiment
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  13. 12 Environmental Protection and Negative Externalities
    1. Introduction to Environmental Protection and Negative Externalities
    2. 12.1 The Economics of Pollution
    3. 12.2 Command-and-Control Regulation
    4. 12.3 Market-Oriented Environmental Tools
    5. 12.4 The Benefits and Costs of U.S. Environmental Laws
    6. 12.5 International Environmental Issues
    7. 12.6 The Tradeoff between Economic Output and Environmental Protection
    8. Key Terms
    9. Key Concepts and Summary
    10. Self-Check Questions
    11. Review Questions
    12. Critical Thinking Questions
    13. Problems
  14. 13 Positive Externalities and Public Goods
    1. Introduction to Positive Externalities and Public Goods
    2. 13.1 Why the Private Sector Underinvests in Innovation
    3. 13.2 How Governments Can Encourage Innovation
    4. 13.3 Public Goods
    5. Key Terms
    6. Key Concepts and Summary
    7. Self-Check Questions
    8. Review Questions
    9. Critical Thinking Questions
    10. Problems
  15. 14 Labor Markets and Income
    1. Introduction to Labor Markets and Income
    2. 14.1 The Theory of Labor Markets
    3. 14.2 Wages and Employment in an Imperfectly Competitive Labor Market
    4. 14.3 Market Power on the Supply Side of Labor Markets: Unions
    5. 14.4 Bilateral Monopoly
    6. 14.5 Employment Discrimination
    7. 14.6 Immigration
    8. Key Terms
    9. Key Concepts and Summary
    10. Self-Check Questions
    11. Review Questions
    12. Critical Thinking Questions
  16. 15 Poverty and Economic Inequality
    1. Introduction to Poverty and Economic Inequality
    2. 15.1 Drawing the Poverty Line
    3. 15.2 The Poverty Trap
    4. 15.3 The Safety Net
    5. 15.4 Income Inequality: Measurement and Causes
    6. 15.5 Government Policies to Reduce Income Inequality
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  17. 16 Information, Risk, and Insurance
    1. Introduction to Information, Risk, and Insurance
    2. 16.1 The Problem of Imperfect Information and Asymmetric Information
    3. 16.2 Insurance and Imperfect Information
    4. Key Terms
    5. Key Concepts and Summary
    6. Self-Check Questions
    7. Review Questions
    8. Critical Thinking Questions
    9. Problems
  18. 17 Financial Markets
    1. Introduction to Financial Markets
    2. 17.1 How Businesses Raise Financial Capital
    3. 17.2 How Households Supply Financial Capital
    4. 17.3 How to Accumulate Personal Wealth
    5. Key Terms
    6. Key Concepts and Summary
    7. Self-Check Questions
    8. Review Questions
    9. Critical Thinking Questions
    10. Problems
  19. 18 Public Economy
    1. Introduction to Public Economy
    2. 18.1 Voter Participation and Costs of Elections
    3. 18.2 Special Interest Politics
    4. 18.3 Flaws in the Democratic System of Government
    5. Key Terms
    6. Key Concepts and Summary
    7. Self-Check Questions
    8. Review Questions
    9. Critical Thinking Questions
    10. Problems
  20. 19 The Macroeconomic Perspective
    1. Introduction to the Macroeconomic Perspective
    2. 19.1 Measuring the Size of the Economy: Gross Domestic Product
    3. 19.2 Adjusting Nominal Values to Real Values
    4. 19.3 Tracking Real GDP over Time
    5. 19.4 Comparing GDP among Countries
    6. 19.5 How Well GDP Measures the Well-Being of Society
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  21. 20 Economic Growth
    1. Introduction to Economic Growth
    2. 20.1 The Relatively Recent Arrival of Economic Growth
    3. 20.2 Labor Productivity and Economic Growth
    4. 20.3 Components of Economic Growth
    5. 20.4 Economic Convergence
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  22. 21 Unemployment
    1. Introduction to Unemployment
    2. 21.1 How Economists Define and Compute Unemployment Rate
    3. 21.2 Patterns of Unemployment
    4. 21.3 What Causes Changes in Unemployment over the Short Run
    5. 21.4 What Causes Changes in Unemployment over the Long Run
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  23. 22 Inflation
    1. Introduction to Inflation
    2. 22.1 Tracking Inflation
    3. 22.2 How to Measure Changes in the Cost of Living
    4. 22.3 How the U.S. and Other Countries Experience Inflation
    5. 22.4 The Confusion Over Inflation
    6. 22.5 Indexing and Its Limitations
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  24. 23 The International Trade and Capital Flows
    1. Introduction to the International Trade and Capital Flows
    2. 23.1 Measuring Trade Balances
    3. 23.2 Trade Balances in Historical and International Context
    4. 23.3 Trade Balances and Flows of Financial Capital
    5. 23.4 The National Saving and Investment Identity
    6. 23.5 The Pros and Cons of Trade Deficits and Surpluses
    7. 23.6 The Difference between Level of Trade and the Trade Balance
    8. Key Terms
    9. Key Concepts and Summary
    10. Self-Check Questions
    11. Review Questions
    12. Critical Thinking Questions
    13. Problems
  25. 24 The Aggregate Demand/Aggregate Supply Model
    1. Introduction to the Aggregate Supply–Aggregate Demand Model
    2. 24.1 Macroeconomic Perspectives on Demand and Supply
    3. 24.2 Building a Model of Aggregate Demand and Aggregate Supply
    4. 24.3 Shifts in Aggregate Supply
    5. 24.4 Shifts in Aggregate Demand
    6. 24.5 How the AD/AS Model Incorporates Growth, Unemployment, and Inflation
    7. 24.6 Keynes’ Law and Say’s Law in the AD/AS Model
    8. Key Terms
    9. Key Concepts and Summary
    10. Self-Check Questions
    11. Review Questions
    12. Critical Thinking Questions
    13. Problems
  26. 25 The Keynesian Perspective
    1. Introduction to the Keynesian Perspective
    2. 25.1 Aggregate Demand in Keynesian Analysis
    3. 25.2 The Building Blocks of Keynesian Analysis
    4. 25.3 The Phillips Curve
    5. 25.4 The Keynesian Perspective on Market Forces
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
  27. 26 The Neoclassical Perspective
    1. Introduction to the Neoclassical Perspective
    2. 26.1 The Building Blocks of Neoclassical Analysis
    3. 26.2 The Policy Implications of the Neoclassical Perspective
    4. 26.3 Balancing Keynesian and Neoclassical Models
    5. Key Terms
    6. Key Concepts and Summary
    7. Self-Check Questions
    8. Review Questions
    9. Critical Thinking Questions
    10. Problems
  28. 27 Money and Banking
    1. Introduction to Money and Banking
    2. 27.1 Defining Money by Its Functions
    3. 27.2 Measuring Money: Currency, M1, and M2
    4. 27.3 The Role of Banks
    5. 27.4 How Banks Create Money
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  29. 28 Monetary Policy and Bank Regulation
    1. Introduction to Monetary Policy and Bank Regulation
    2. 28.1 The Federal Reserve Banking System and Central Banks
    3. 28.2 Bank Regulation
    4. 28.3 How a Central Bank Executes Monetary Policy
    5. 28.4 Monetary Policy and Economic Outcomes
    6. 28.5 Pitfalls for Monetary Policy
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  30. 29 Exchange Rates and International Capital Flows
    1. Introduction to Exchange Rates and International Capital Flows
    2. 29.1 How the Foreign Exchange Market Works
    3. 29.2 Demand and Supply Shifts in Foreign Exchange Markets
    4. 29.3 Macroeconomic Effects of Exchange Rates
    5. 29.4 Exchange Rate Policies
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  31. 30 Government Budgets and Fiscal Policy
    1. Introduction to Government Budgets and Fiscal Policy
    2. 30.1 Government Spending
    3. 30.2 Taxation
    4. 30.3 Federal Deficits and the National Debt
    5. 30.4 Using Fiscal Policy to Fight Recession, Unemployment, and Inflation
    6. 30.5 Automatic Stabilizers
    7. 30.6 Practical Problems with Discretionary Fiscal Policy
    8. 30.7 The Question of a Balanced Budget
    9. Key Terms
    10. Key Concepts and Summary
    11. Self-Check Questions
    12. Review Questions
    13. Critical Thinking Questions
    14. Problems
  32. 31 The Impacts of Government Borrowing
    1. Introduction to the Impacts of Government Borrowing
    2. 31.1 How Government Borrowing Affects Investment and the Trade Balance
    3. 31.2 Fiscal Policy and the Trade Balance
    4. 31.3 How Government Borrowing Affects Private Saving
    5. 31.4 Fiscal Policy, Investment, and Economic Growth
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  33. 32 Macroeconomic Policy Around the World
    1. Introduction to Macroeconomic Policy around the World
    2. 32.1 The Diversity of Countries and Economies across the World
    3. 32.2 Improving Countries’ Standards of Living
    4. 32.3 Causes of Unemployment around the World
    5. 32.4 Causes of Inflation in Various Countries and Regions
    6. 32.5 Balance of Trade Concerns
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  34. 33 International Trade
    1. Introduction to International Trade
    2. 33.1 Absolute and Comparative Advantage
    3. 33.2 What Happens When a Country Has an Absolute Advantage in All Goods
    4. 33.3 Intra-industry Trade between Similar Economies
    5. 33.4 The Benefits of Reducing Barriers to International Trade
    6. Key Terms
    7. Key Concepts and Summary
    8. Self-Check Questions
    9. Review Questions
    10. Critical Thinking Questions
    11. Problems
  35. 34 Globalization and Protectionism
    1. Introduction to Globalization and Protectionism
    2. 34.1 Protectionism: An Indirect Subsidy from Consumers to Producers
    3. 34.2 International Trade and Its Effects on Jobs, Wages, and Working Conditions
    4. 34.3 Arguments in Support of Restricting Imports
    5. 34.4 How Governments Enact Trade Policy: Globally, Regionally, and Nationally
    6. 34.5 The Tradeoffs of Trade Policy
    7. Key Terms
    8. Key Concepts and Summary
    9. Self-Check Questions
    10. Review Questions
    11. Critical Thinking Questions
    12. Problems
  36. A | The Use of Mathematics in Principles of Economics
  37. B | Indifference Curves
  38. C | Present Discounted Value
  39. D | The Expenditure-Output Model
  40. Answer Key
    1. Chapter 1
    2. Chapter 2
    3. Chapter 3
    4. Chapter 4
    5. Chapter 5
    6. Chapter 6
    7. Chapter 7
    8. Chapter 8
    9. Chapter 9
    10. Chapter 10
    11. Chapter 11
    12. Chapter 12
    13. Chapter 13
    14. Chapter 14
    15. Chapter 15
    16. Chapter 16
    17. Chapter 17
    18. Chapter 18
    19. Chapter 19
    20. Chapter 20
    21. Chapter 21
    22. Chapter 22
    23. Chapter 23
    24. Chapter 24
    25. Chapter 25
    26. Chapter 26
    27. Chapter 27
    28. Chapter 28
    29. Chapter 29
    30. Chapter 30
    31. Chapter 31
    32. Chapter 32
    33. Chapter 33
    34. Chapter 34
  41. References
  42. Index

By the end of this section, you will be able to:

  • Interpret a circular flow diagram
  • Explain the importance of economic theories and models
  • Describe goods and services markets and labor markets
The image is a photograph of John Maynard Keynes.
Figure 1.5 John Maynard Keynes One of the most influential economists in modern times was John Maynard Keynes. (Credit: Wikimedia Commons)

John Maynard Keynes (1883–1946), one of the greatest economists of the twentieth century, pointed out that economics is not just a subject area but also a way of thinking. Keynes (Figure 1.5) famously wrote in the introduction to a fellow economist’s book: “[Economics] is a method rather than a doctrine, an apparatus of the mind, a technique of thinking, which helps its possessor to draw correct conclusions.” In other words, economics teaches you how to think, not what to think.

Link It Up

Watch this video about John Maynard Keynes and his influence on economics.

Economists see the world through a different lens than anthropologists, biologists, classicists, or practitioners of any other discipline. They analyze issues and problems using economic theories that are based on particular assumptions about human behavior. These assumptions tend to be different than the assumptions an anthropologist or psychologist might use. A theory is a simplified representation of how two or more variables interact with each other. The purpose of a theory is to take a complex, real-world issue and simplify it down to its essentials. If done well, this enables the analyst to understand the issue and any problems around it. A good theory is simple enough to understand, while complex enough to capture the key features of the object or situation you are studying.

Sometimes economists use the term model instead of theory. Strictly speaking, a theory is a more abstract representation, while a model is a more applied or empirical representation. We use models to test theories, but for this course we will use the terms interchangeably.

For example, an architect who is planning a major office building will often build a physical model that sits on a tabletop to show how the entire city block will look after the new building is constructed. Companies often build models of their new products, which are more rough and unfinished than the final product, but can still demonstrate how the new product will work.

A good model to start with in economics is the circular flow diagram (Figure 1.6). It pictures the economy as consisting of two groups—households and firms—that interact in two markets: the goods and services market in which firms sell and households buy and the labor market in which households sell labor to business firms or other employees.

The circular flow diagram’s outer arrows represent a goods and services market, and the inner arrows represent a labor market. As illustrated by the outer arrows, in a goods and services market, firms give goods and services to households and, in exchange, households give payment to firms. As illustrated by the inner arrows, in a labor market, households provide labor to firms and, in exchange, firms give wages, salaries, and benefits to households.
Figure 1.6 The Circular Flow Diagram The circular flow diagram shows how households and firms interact in the goods and services market, and in the labor market. The direction of the arrows shows that in the goods and services market, households receive goods and services and pay firms for them. In the labor market, households provide labor and receive payment from firms through wages, salaries, and benefits.

Firms produce and sell goods and services to households in the market for goods and services (or product market). Arrow “A” indicates this. Households pay for goods and services, which becomes the revenues to firms. Arrow “B” indicates this. Arrows A and B represent the two sides of the product market. Where do households obtain the income to buy goods and services? They provide the labor and other resources (e.g. land, capital, raw materials) firms need to produce goods and services in the market for inputs (or factors of production). Arrow “C” indicates this. In return, firms pay for the inputs (or resources) they use in the form of wages and other factor payments. Arrow “D” indicates this. Arrows “C” and “D” represent the two sides of the factor market.

Of course, in the real world, there are many different markets for goods and services and markets for many different types of labor. The circular flow diagram simplifies this to make the picture easier to grasp. In the diagram, firms produce goods and services, which they sell to households in return for revenues. The outer circle shows this, and represents the two sides of the product market (for example, the market for goods and services) in which households demand and firms supply. Households sell their labor as workers to firms in return for wages, salaries, and benefits. The inner circle shows this and represents the two sides of the labor market in which households supply and firms demand.

This version of the circular flow model is stripped down to the essentials, but it has enough features to explain how the product and labor markets work in the economy. We could easily add details to this basic model if we wanted to introduce more real-world elements, like financial markets, governments, and interactions with the rest of the globe (imports and exports).

Economists carry a set of theories in their heads like a carpenter carries around a toolkit. When they see an economic issue or problem, they go through the theories they know to see if they can find one that fits. Then they use the theory to derive insights about the issue or problem. Economists express theories as diagrams, graphs, or even as mathematical equations. (Do not worry. In this course, we will mostly use graphs.) Economists do not figure out the answer to the problem first and then draw the graph to illustrate. Rather, they use the graph of the theory to help them figure out the answer. Although at the introductory level, you can sometimes figure out the right answer without applying a model, if you keep studying economics, before too long you will run into issues and problems that you will need to graph to solve. We explain both micro and macroeconomics in terms of theories and models. The most well-known theories are probably those of supply and demand, but you will learn a number of others.

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