Thinking Like An Economist

1. Thinking LikeAn Economist

2. Introduction • What is the Optimal Class Size? • To maximize learning without consideration of cost? • How would considering costs change our answer? • A personal tutorial course in economics might cost $40,000 • A class of 300 students might cost $200/student Chapter 1: Thinking Like an Economist

3. Introduction • What is the Optimal Class Size? • What trade-offs must university administrators and students consider when choosing class size? Chapter 1: Thinking Like an Economist

4. Economics: StudyingChoice In a World of Scarcity • The Scarcity Principle • Boundless wants cannot be satisfied with limited resources. • Therefore, having more of one thing usually means having less of another. • Because of scarcity we must make choices. Chapter 1: Thinking Like an Economist

5. Scarcity Choices Economics: StudyingChoice In a World of Scarcity Wants vs. Resources Chapter 1: Thinking Like an Economist

6. Economics: StudyingChoice In a World of Scarcity • Economics • The study of how people make choices under conditions of scarcity and of the results of those choices for society. Chapter 1: Thinking Like an Economist

7. Economics: StudyingChoice In a World of Scarcity • The Cost-Benefit Principle • An individual (or a firm or a society) should take an action if, and only if, the extra benefits from taking the action are at least as great as the extra costs Chapter 1: Thinking Like an Economist

8. Economics: StudyingChoice In a World of Scarcity • Choosing the Optimal Class Size Revisited • Assumptions: • Two class sizes: 100 and 20 • Introductory economics classes currently have 100 students • Question • Should the class size be reduced to 20 students? Chapter 1: Thinking Like an Economist

9. Economics: StudyingChoice In a World of Scarcity • Observations • The “best” class from an economic point of view will generally not be the same as the “best” size from the point of view of an educational psychologist. • People will feel differently about the value of smaller classes. Chapter 1: Thinking Like an Economist

10. Economics: StudyingChoice In a World of Scarcity • Application • What other examples of scarcity and trade-offs can we identify? Chapter 1: Thinking Like an Economist

11. Economics: StudyingChoice In a World of Scarcity • Choosing the Optimal Class Size • Assume: • The cost of a class with 20 students is $1,000 per student more than a class of 100 students • What do you think: • Would it be a good idea to reduce the class size? Chapter 1: Thinking Like an Economist

12. Applying The Cost-Benefit Principle • Rational Person • Someone with well-defined goals who tries to fulfill those goals as best he or she can Chapter 1: Thinking Like an Economist

13. Applying The Cost-Benefit Principle • Should you walk downtown to save $10 on a $25 computer game? • The benefit of going downtown = $10 • The cost of going downtown is the dollar value of everything you give up to go downtown Chapter 1: Thinking Like an Economist

14. Applying The Cost-Benefit Principle • Should you walk downtown to save $10 on a $25 computer game? • Estimating the cost: • How much would someone have to pay you to walk downtown? • If you would walk downtown for $9; the trip’s cost is $9 • The benefit ($10) exceeds the cost of ($9) of buying the game downtown Chapter 1: Thinking Like an Economist

15. Applying The Cost-Benefit Principle • Question • Will everyone choose to buy the computer game downtown? Chapter 1: Thinking Like an Economist

16. Applying The Cost-Benefit Principle • Economic Surplus • The benefit of taking any action minus its cost • The goal of economic decision makers is to maximize their economic surplus Chapter 1: Thinking Like an Economist

17. Applying The Cost-Benefit Principle • Opportunity Cost • The value of the next-best alternative that must be forgone to undertake an activity Chapter 1: Thinking Like an Economist

18. Applying The Cost-Benefit Principle • Question • What is the opportunity cost of buying the game downtown? Chapter 1: Thinking Like an Economist

19. Applying The Cost-Benefit Principle • Assume • The benefit of buying the game downtown is $10 • The cost of making the trip is $12 • Questions • What is your economic surplus from buying the game downtown? • Where should you buy the game? Chapter 1: Thinking Like an Economist

20. Applying The Cost-Benefit Principle • The Role of Economic Models • Economic models are abstract (simplified descriptions) models that allow us to analyze situations in a logical way • Other examples of abstract models • A computer model of climate change • A road map Chapter 1: Thinking Like an Economist

21. Applying The Cost-Benefit Principle • Observation • The cost-benefit principle suggests that we take only those actions that create additional economic surplus. Chapter 1: Thinking Like an Economist

22. Four Important Decision Pitfalls • Pitfall 1: Measuring cost and benefits as proportions rather than absolute dollar amounts • Examples: • Should you walk downtown to save $10 on a $2,020 laptop computer? • Which is more valuable, saving $100 on a $2,000 plane ticket to Tokyo or saving $90 on a $200 plane ticket to Chicago? Chapter 1: Thinking Like an Economist

23. Four Important Decision Pitfalls • Pitfall 2: Ignoring Opportunity Costs • Example: • Should you use your frequent-flyer coupon to fly to Fort Lauderdale for spring break? • Assume: • Round trip airfare is $500 and is equal to your frequent flyer coupon • Other costs equal $1,000 Chapter 1: Thinking Like an Economist

24. Four Important Decision Pitfalls • Pitfall 2: Ignoring Opportunity Costs • Assume (cont): • The most you are willing to pay for the Fort Lauderdale trip is $1,350 • Alternate use for the frequent flyer coupon is to attend a wedding in Boston the week after spring break and the Boston airfare is $400 (coupon expires just after the wedding) Chapter 1: Thinking Like an Economist

25. Four Important Decision Pitfalls • Pitfall 2: Ignoring Opportunity Costs • Example: • Should you use your frequent flyer coupon to fly to Fort Lauderdale for spring break? • Without the coupon: • Benefits = $1,350 • Cost = $1,400 ($400 opportunity cost + $1,000 other costs) • Question • What would you do if the coupon expires just after spring break? Chapter 1: Thinking Like an Economist

26. Four Important Decision Pitfalls • Pitfall 2: Ignoring Opportunity Costs • The key to using the concept of opportunity cost correctly lies in recognizing precisely what taking a given action prevents us from doing. Chapter 1: Thinking Like an Economist

27. Four Important Decision Pitfalls • Pitfall 3: Failure To Ignore Sunk Costs • The only costs that should influence a decision about whether to take an action are those that we can avoid by not taking the action Chapter 1: Thinking Like an Economist

28. Four Important Decision Pitfalls • Pitfall 3: Failure To Ignore Sunk Costs • Sunk cost • A cost that is beyond recovery at the moment a decision must be made Chapter 1: Thinking Like an Economist

29. Four Important Decision Pitfalls • Pitfall 3: Failure To Ignore Sunk Costs • Example • How much should you eat at an all-you-can-eat restaurant? • Assume: • Price = $5 • 20 randomly selected guests will get lunch on the house Chapter 1: Thinking Like an Economist

30. Four Important Decision Pitfalls • Pitfall 3: Failure To Ignore Sunk Costs • Example • How much should you eat at an all-you-can-eat restaurant? • Question: • If all diners are rational, will there be any difference in the average quantity of food consumed by these two groups? Chapter 1: Thinking Like an Economist

31. Four Important Decision Pitfalls • Pitfall 4: Failure To Understand the Average-Marginal Distinction • Marginal Benefit • The increase in total benefit that results from carrying out one additional unit of an activity Chapter 1: Thinking Like an Economist

32. Four Important Decision Pitfalls • Pitfall 4: Failure To Understand the Average-Marginal Distinction • Marginal Cost • The increase in total cost that results from carrying out one additional unit of an activity Chapter 1: Thinking Like an Economist

33. Four Important Decision Pitfalls • Pitfall 4: Failure To Understand the Average-Marginal Distinction • Example • Should NASA expand the space shuttle program from four launches per year to five? • Benefits • $24 billion (average of $6 billion/launch) • Costs • $20 billion (average of $5 billion/launch) Chapter 1: Thinking Like an Economist

34. Four Important Decision Pitfalls • Pitfall 4: Failure To Understand the Average-Marginal Distinction • Average Cost • The total cost of undertaking n units of an activity divided by n Chapter 1: Thinking Like an Economist

35. Four Important Decision Pitfalls • Pitfall 4: Failure To Understand the Average-Marginal Distinction • Average Benefit • The total benefit of undertaking n units of an activity divided by n Chapter 1: Thinking Like an Economist

36. 0 0 0 1 3 3 2 7 3.5 3 12 4 4 20 5 5 32 6.4 3 4 5 8 12 Assume: Average Benefit = Marginal Benefit = $6 billion Four Important Decision Pitfalls # of Launches Total Cost Average Cost Marginal Cost ($ billion) ($ billion/launch) ($ billion/launch) What is the optimal number of launches? Chapter 1: Thinking Like an Economist

37. Normative Economicsvs. Positive Economics • Normative Economic Principle • One that says how people should behave • Example: Cost-benefit principle • Positive Economic Principle • One that predicts how people will behave • Example: The incentives matter principle • A person (or a firm or society) is more likely to take an action if its benefit rises and less likely if its cost rises) Chapter 1: Thinking Like an Economist

38. Economics: Micro and Macro • Microeconomics • The study of individual choice under scarcity and its implications for the behavior of prices and quantities in individual markets Chapter 1: Thinking Like an Economist

39. Economics: Micro and Macro • Macroeconomics • The study of the performance of national economies, and of the policies that governments use to try to improve that performance Chapter 1: Thinking Like an Economist

40. The Approach of This Text • Focus on core economic concepts • Scarcity principle • Cost-benefit principle • Incentive principle • Learning economics through applications Chapter 1: Thinking Like an Economist

41. Economic Naturalism • Using insights from economics to help make sense of observations from everyday life Chapter 1: Thinking Like an Economist

42. Economic Naturalism • Question • Why do so many computer hardware manufacturers include more than $1,000 worth of “free” software with a computer selling for only slightly more than that? Chapter 1: Thinking Like an Economist

43. Economic Naturalism • Questions • Why don’t automobile manufacturers make cars without heaters? • Why do the keypad buttons on drive-up automatic teller machines have Braille dots? Chapter 1: Thinking Like an Economist

44. Economic Naturalism • Applications • Use cost-benefit analysis to explain some pattern of events or behavior you have observed in your own environment Chapter 1: Thinking Like an Economist

45. End of Chapter