Opportunity cost

In economics, opportunity cost, or economic cost, is the cost of something in terms of an opportunity forgone (and the benefits that could be received from that opportunity), or the most valuable forgone alternative, i.e. the second best alternative. For example, if a city decides to build a hospital on vacant land that it owns, the opportunity cost is some other thing that might have been done with the land and construction funds instead. In building the hospital, the city has forgone the opportunity to build a sporting center on that land, or a parking lot, or the ability to sell the land to reduce the city's debt, and so on.

Opportunity cost need not be assessed in monetary terms, but rather can be assessed in terms of anything that is of value to the person or persons doing the assessing. For example, a person who chooses to watch, or to record, a television program cannot watch (or record) any other at the same time. (The rule still applies if the recording device can simultaneously record multiple programs; there is going to be a limit, and if the number of desired programs exceeds the capacity of the recorder, some of them will not be saved, and thus cannot be seen.) In any case, at the time the person chooses to watch a program, either live or on a recording, they cannot watch something else, and if they are not able to record another program showing at the same time, the opportunity to view it is lost (presuming the particular program is not repeated). Or another example, someone having a video game can choose to watch a program or play the video game on the TV; they can't do both simultaneously. Whichever one they choose is a lost opportunity to experience the other.

Assessing opportunity costs is fundamental to assessing the true cost of any course of action. In the case where there is no explicit accounting or monetary the land for a parking lot, or the money that could have been made from selling the land, or the loss of any of the various other possible uses -- but not all of these in aggregate, because the land cannot be used for more than one of these purposes.

However, most opportunities are difficult to compare. Opportunity cost has been seen as the foundation of the marginal theory of value.

In some cases it may be possible to have more of everything by making different choices; for instance, when an economy is within its production possibility frontier. In microeconomic models this is unusual, because individuals are assumed to maximise utility, but it is a feature of Keynesian macroeconomics. In these circumstances opportunity cost is a less useful concept.