Prepared by:
Fernando & Yvonn Quijano
© 2007 Worth Publishers Essentials of Economics Krugman • Wells • Olney
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What you will learn in
this chapter:
➤ A set of principles for
understanding the
economics of how
individuals make choices
➤ A set of principles for
understanding how
individual choices interact
One must choose
© 2007 Worth Publishers Essentials of Economics Krugman • Wells • Olney
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Individual Choice: The Core of Economics
Individual choice is the decision by an individual
of what to do, which necessarily involves a
decision of what not to do.
TABLE 1-1
Principles That Underlie the Economics of
Individual Choice
1.
2.
3.
4.
Resources are scarce.
The real cost of something is what you must
give up to get it.
“How much?” is a decision at the margin.
People usually exploit opportunities to make
themselves better off.
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Individual Choice: The Core of Economics
Resources Are Scarce
A resource is anything that can be used to produce
something else.
Resources are scarce—the quantity available isn’t
large enough to satisfy all productive uses.
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Individual Choice: The Core of Economics
Opportunity Cost: The Real Cost of
Something Is What You Must Give Up to Get It
The real cost of an item is its opportunity
cost: what you must give up in order to
get it.
Tiger Woods understood
the concept of opportunity
cost. The rest is history.
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Individual Choice: The Core of Economics
“How Much?” Is a Decision at the Margin
You make a trade-off when you compare
the costs with the benefits of doing
something.
Decisions about whether to do a bit more or
a bit less of an activity are marginal
decisions. The study of such decisions is
known as marginal analysis.
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Individual Choice: The Core of Economics
People Usually Exploit Opportunities to Make
Themselves Better Off
An incentive is anything that offers rewards
to people who change their behavior.
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Individual Choice: The Core of Economics
Individual Choice: Summing It Up
We have just seen that there are four basic principles
of individual choice:
■ Resources are scarce. It is always necessary to
make choices.
■ The real cost of something is what you must give
up to get it. All costs are opportunity costs.
■ “How much?” is a decision at the margin. Usually
the question is not “whether,” but “how much. And
that is a question whose answer hinges on the
costs and benefits of doing a bit more.
■ People usually exploit opportunities to make
themselves better off. As a result, people will
respond to incentives.
© 2007 Worth Publishers Essentials of Economics Krugman • Wells • Olney
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Interaction: How Economies Work
Interaction of choices—my choices affect your
choices, and vice versa—is a feature of most
economic situations. The results of this interaction
are often quite different from what the individuals
intend.
TABLE 1-2
Principles That Underlie the
Interaction of Individual Choices
1. There are gains from trade.
2. Markets move toward equilibrium.
3. Resources should be used as efficiently as
possible to achieve society’s goals.
4. Markets usually lead to efficiency.
5. When markets don’t achieve efficiency,
government intervention can improve society’s
welfare.
© 2007 Worth Publishers Essentials of Economics Krugman • Wells • Olney
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Interaction: How Economies Work
There Are Gains from Trade
“I hunt and she gathers-otherwise we couldn’t make ends meet.”
© 2007 Worth Publishers Essentials of Economics Krugman • Wells • Olney
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Interaction: How Economies Work
There Are Gains from Trade
In a market economy, individuals engage in trade:
They provide goods and services to others and
receive goods and services in return.
There are gains from trade: people can get more
of what they want through trade than they could if
they tried to be self-sufficient. This increase in
output is due to specialization: each person
specializes in the task that he or she is good at
performing.
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Interaction: How Economies Work
Markets Move Toward Equilibrium
An economic situation is in equilibrium
when no individual would be better off doing
something different.
Witness equilibrium in
action at the checkout
lines in your neighborhood
supermarket.
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Interaction: How Economies Work
Resources Should Be Used as Efficiently
as Possible to Achieve Society’s Goals
An economy is efficient if it takes all
opportunities to make some people better off
without making other people worse off.
Equity means that everyone gets his or
her fair share. Since people can disagree
about what’s “fair,” equity isn’t as welldefined a concept as efficiency.
© 2007 Worth Publishers Essentials of Economics Krugman • Wells • Olney
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Interaction: How Economies Work
Markets Usually Lead to Efficiency
The incentives built into a market economy already
ensure that resources are usually put to good use,
that opportunities to make people better off are not
wasted.
© 2007 Worth Publishers Essentials of Economics Krugman • Wells • Olney
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Interaction: How Economies Work
When Markets Don’t Achieve Efficiency, Government
Intervention Can Improve Society’s Welfare
A very important branch of economics is devoted to
studying why markets fail and what policies should be
adopted to improve social welfare. They fail for three
principal reasons:
■ Individual actions have side effects that are not
properly taken into account by the market.
■ One party prevents mutually beneficial trades from
occurring in the attempt to capture a greater share
of resources for itself.
■ Some goods, by their very nature, are unsuited for
efficient management by markets.
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KEY TERMS
Individual choice
Interaction
Resource
Trade
Scarce
Gains from trade
Opportunity cost
Specialization
Trade-off
Equilibrium
Marginal decisions
Efficient
Marginal analysis
Equity
Incentive
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