C H A P T E R

Principles of Microeconomics

E P R I N C I P L E S O F

conomics

N. Gregory Mankiw

© 2009 South-Western, a part of Cengage Learning, all rights reserved

In this section, we will cover:



What is Economics?



Basic Principles



Production Possibilities Frontier



Economists as Policy Advisors

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Economy. . .

. . . The word

economy

comes from a Greek word for “one who manages a household.” Definition of

Economics

: the study of how society manages its scarce resources.

How do we go from managing a household to managing an economy?

A household and an economy face many decisions:   Who will work?

What goods and how many of them should be produced?

  What resources should be used in production?

At what price should the goods be sold?

  Society and Scarce Resources: The management of society’s resources is important because resources are scarce.



Scarcity

. . . means that society has limited resources and therefore cannot produce all the goods and services people wish to have.

Microeconomics and Macroeconomics



Microeconomics

is the study of how households and firms make decisions and how they interact in markets. 

Macroeconomics

is the study of economy-wide phenomena, including inflation, unemployment, and economic growth.  These two branches of economics are closely intertwined, yet distinct – they address different questions. 5

HOW PEOPLE MAKE DECISIONS Principle #1: People Face Tradeoffs

All decisions involve tradeoffs.  Society faces an important tradeoff:

efficiency vs. equality



Efficiency

: when society gets the most from its scarce resources 

Equality

: when prosperity is distributed uniformly among society’s members 6

HOW PEOPLE MAKE DECISIONS Principle #2: The Cost of Something Is What You Give Up to Get It

 Making decisions requires comparing the costs and benefits of alternative choices.  The

opportunity cost

of any item is whatever must be given up to obtain it.  It is the relevant cost for decision making.

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HOW PEOPLE MAKE DECISIONS Principle #3: Rational People Think at the Margin Principle #4: People Respond to Incentives Principle #5: Trade Can Make Everyone Better Off

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HOW PEOPLE INTERACT Principle #6: Markets Are Usually A Good Way to Organize Economic Activity

 The invisible hand works through the price system:  The interaction of buyers and sellers determines prices.  Each price reflects the good’s value to buyers and the cost of producing the good.  Prices guide self-interested households and firms to make decisions that, in many cases, maximize society’s economic well-being. 9

HOW PEOPLE INTERACT Principle #7: Governments Can Sometimes Improve Market Outcomes Principle #8: A country’s standard of living depends on its ability to produce goods & services. Principle #9: Prices rise when the government prints too much money.

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Section 2 Models and Perspectives

This section introduces: Production Possibility Frontier Positive vs. normative statements Why economists disagree!

13

Our Second Model:

The Production Possibilities Frontier

 The

Production Possibilities Frontier (PPF)

: a graph that shows the combinations of two goods the economy can possibly produce given the available resources and the available technology  Example:    Two goods: computers and wheat One resource: labor (measured in hours) Economy has 50,000 labor hours per month available for production.

THINKING LIKE AN ECONOMIST

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Point on graph Production Com puters Soju A 500 0 B C 400 250 1,000 2,500 D E 100 0 4,000 5,000

Tradeoff is based on opportunity cost!

PPF Example Soju (trucks)

6,000 5,000

E

4,000 3,000 2,000 1,000 0 0

D C B

100 200 300 400 500

A

600

Computers

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Economic Growth and the PPF

With additional resources or an improvement in technology, the economy can produce more computers, more wheat, or any combination in between.

THINKING LIKE AN ECONOMIST

Wheat (tons)

6,000 5,000 4,000 3,000 2,000 1,000 0 0 Economic growth shifts the PPF outward.

100 200 300 400 500 600

Computers

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The Economist as Policy Advisor

 As scientists, economists make

positive statements

, which attempt to describe the world as it is.   As policy advisors, economists make

normative statements

, which attempt to prescribe how the world should be.  Positive statements can be confirmed or refuted, normative statements cannot. Govt employs many economists for policy advice.

E.g.,

the U.S. President has a Council of Economic Advisors, which the author of this textbook chaired from 2003 to 2005. 17

Why Economists Disagree

 Economists often give conflicting policy advice.  They sometimes disagree about the validity of alternative positive theories about the world.  They may have different values and, therefore, different normative views about what policy should try to accomplish.  Yet, there are many propositions about which most economists agree.

THINKING LIKE AN ECONOMIST

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