Pareto Efficiency

Pareto Efficiency

Markets weed out inefficient processes, but only when no one has sufficient power to manipulate them.

—Ha-Joon Chang

Efficiency can mean different things. A video-game player might seek the most points in the least time. A producer might seek more output from the same inputs. These are questions about using resources to achieve an objective.

In economics, “efficiency” also concerns allocation. A Pareto improvement is a feasible change that makes at least one person better off without making anyone worse off. An allocation is Pareto efficient when no such improvement remains. The concept is named for Vilfredo Pareto.

Market power or poor information can prevent mutually beneficial changes. Economists describe such inefficient market outcomes as “market failure.” Identifying a particular failure requires examining how the market works and whose costs and benefits are counted.

Pareto efficiency is a limited test. Many distributions can satisfy it, including highly unequal ones. It does not require that everyone have what they need, that every firm earn the highest possible profit, or that total satisfaction be as large as possible. A change that helps many people while imposing a cost on someone else may be desirable under another criterion, but it is not a Pareto improvement unless that person is also left no worse off.

Changing resources and preferences

Imagine a drought destroys the apple crop. People who wanted apples lose something they valued. Switching to oranges may help them adapt, but it does not necessarily restore their previous well-being without a cost to anyone. The drought changes what allocations are feasible. Within those new constraints, people can look for trades or adjustments that benefit someone without harming others.

An allocation that was efficient under one set of resources, preferences, and technologies may leave opportunities for improvement after those conditions change. Maintaining efficiency therefore involves finding and assessing new possibilities, rather than preserving one arrangement forever.

Information and market outcomes

Information can help people discover available goods, compare alternatives, and identify gains from trade. No participant knows everything, and differences in knowledge can affect the terms on which people trade. More information is useful when it helps participants understand the relevant choices and consequences.

The Internet moves us closer to “perfect information” on markets. Individuals and companies alike can buy and sell across borders and jurisdictions wherever they find the best match of supply and demand.

—Milton Friedman

Efficiency also depends on the preferences being considered. People buy necessities, but they also buy status. Thorstein Veblen called the latter “conspicuous consumption” and argued that it “diverts economic energy from the production of what people really need into what they can show off with.” That is a criticism of what production serves. A market can satisfy preferences for display while leaving basic needs unmet; Pareto efficiency alone does not resolve that conflict.

To apply the model, specify the feasible change and ask who benefits and who bears a cost. When someone would be worse off, the decision requires an explicit judgment about that tradeoff rather than an assumption that efficiency settles it.