Imagine you and a friend are walking down the streetand a $100 bill magically appears. You would likelyshare the money evenly, each taking $50, deeming thisthe fairest division. According to Pareto efficiency, however,any allocation of the $100 would be optimal — including thedistribution you would likely prefer: keeping all $100 foryourself.Pareto efficiency says that an allocation is efficient if anaction makes some individual better off and no individualworse off. The concept was developed by Vilfredo Pareto, anItalian economist and sociologist known for his applicationof mathematics to economic analysis, and particularly for hisManual of Political Economy (1906).Pareto used this work to develophis theory of pure economics,analyze “ophelimity,” his ownterm indicating the power ofgiving satisfaction, and introduceindifference curves. Indoing so, he laid the foundationof modern welfare economics.Because the two individualsin the opening example willnot lose any of the money theyoriginally held, they cannot endup worse off than they started.Any additional amount ofmoney that they receive willmake them better off. If oneindividual keeps all $100, theother will be as well off as hewas before the money appeared. Whether the money issplit evenly or one individual keeps more than the other,Pareto efficiency is achieved.Consider another example: the sale of a used car. Theseller may value the car at $10,000, while the buyer iswilling to pay $15,000 for it. A deal in which the car is sold
for $12,500 would be Pareto efficient because both the
seller and the buyer are better off as a result of the trade. In
this case, they are better off by the same amount: $2,500.
However, any price between $10,000 and $15,000 is Pareto
efficient because the seller receives more value in money
than the value he places on the car, and the buyer values the
car more than the money he pays for it.
Pareto efficiency has applications in game theory,
multicriteria decisionmaking, engineering, and many of
the social sciences. It is a central principle in economics.
In general, an economic allocation problem has several
possible Pareto efficient outcomes. In the marketplace, the
competitive equilibrium is typically included among them.
A major drawback of Pareto efficiency, some ethicists claim,
is that it does not suggest which of the Pareto efficient
outcomes is best.
Furthermore, the concept does not require an equitable
distribution of wealth, nor does it necessarily suggest taking
remedial steps to correct for existing inequality. If the
incomes of the wealthy increase while the incomes of everyone
else remain stable, such a change is Pareto efficient.
Martin Feldstein, an economist at Harvard University and
president of the National Bureau of Economic Research,
explains that some see this as unfair. Such critics, while conceding
that the outcome is Pareto
efficient, might complain: “I don’t
have fewer material goods, but I
have the extra pain of living in a
more unequal world.” In short,
they are concerned about not only
a person’s absolute position but
also his relative position, and
argue that, as a result, Paretian
analysis has little to offer.
Feldstein rejects this argument
and maintains that Pareto efficiency
is a good guiding principle
for economists, even if some
actions that promote Pareto
efficiency lead to increases
in income inequality. Instead,
Feldstein argues that we should
focus on poverty, and to do this
we should not stifle changes that would increase the total
economic pie just because they would also produce
outcomes that would initially increase inequality.
In general, rich societies can more effectively deal with
such problems than poor ones. For instance, would you
rather live in a country that has almost perfect income
equality but is desperately poor or one that has quite a bit
of income inequality but is rich enough to help out its most
unfortunate citizens? Most people would choose the latter.
That said, Pareto efficiency may not be the only
benchmark that a society may wish to use in choosing
between alternative public policies. It can be a very helpful
guide — and, indeed, has enriched economic analysis a
great deal — but as Pareto himself wrote, “Political economy
does not have to take morality into account. But one who
extols some practical measure ought to take into account not
only the economic consequences, but also the moral,
religious, political, etc., consequences.” R
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