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Sunk costs

In the budget constraint framework, all decisions involve what will happen next: that is, what quantities of goods will you consume, how many hours will you work, or how much will you save. These decisions do not look back to past choices. Thus, the budget constraint framework assumes that sunk costs    , which are costs that were incurred in the past and cannot be recovered, should not affect the current decision.

Consider the case of Selena, who pays $8 to see a movie, but after watching the film for 30 minutes, she knows that it is truly terrible. Should she stay and watch the rest of the movie because she paid for the ticket, or should she leave? The money she spent is a sunk cost, and unless the theater manager is feeling kindly, Selena will not get a refund. But staying in the movie still means paying an opportunity cost in time. Her choice is whether to spend the next 90 minutes suffering through a cinematic disaster or to do something—anything—else. The lesson of sunk costs is to forget about the money and time that is irretrievably gone and instead to focus on the marginal costs and benefits of current and future options.

For people and firms alike, dealing with sunk costs can be frustrating. It often means admitting an earlier error in judgment. Many firms, for example, find it hard to give up on a new product that is doing poorly because they spent so much money in creating and launching the product. But the lesson of sunk costs is to ignore them and make decisions based on what will happen in the future.

From a model with two goods to one of many goods

The budget constraint diagram containing just two goods, like most models used in this book, is not realistic. After all, in a modern economy people choose from thousands of goods. However, thinking about a model with many goods is a straightforward extension of what we discussed here. Instead of drawing just one budget constraint, showing the tradeoff between two goods, you can draw multiple budget constraints, showing the possible tradeoffs between many different pairs of goods. Or in more advanced classes in economics, you would use mathematical equations that include many possible goods and services that can be purchased, together with their quantities and prices, and show how the total spending on all goods and services is limited to the overall budget available. The graph with two goods that was presented here clearly illustrates that every choice has an opportunity cost, which is the point that does carry over to the real world.

Key concepts and summary

Economists see the real world as one of scarcity: that is, a world in which people’s desires exceed what is possible. As a result, economic behavior involves tradeoffs in which individuals, firms, and society must give up something that they desire to obtain things that they desire more. Individuals face the tradeoff of what quantities of goods and services to consume. The budget constraint, which is the frontier of the opportunity set, illustrates the range of choices available. The slope of the budget constraint is determined by the relative price of the choices. Choices beyond the budget constraint are not affordable.

Opportunity cost measures cost by what is given up in exchange. Sometimes opportunity cost can be measured in money, but it is often useful to consider time as well, or to measure it in terms of the actual resources that must be given up.

Most economic decisions and tradeoffs are not all-or-nothing. Instead, they involve marginal analysis, which means they are about decisions on the margin, involving a little more or a little less. The law of diminishing marginal utility points out that as a person receives more of something—whether it is a specific good or another resource—the additional marginal gains tend to become smaller. Because sunk costs occurred in the past and cannot be recovered, they should be disregarded in making current decisions.


Use this information to answer the following 4 questions: Marie has a weekly budget of $24, which she likes to spend on magazines and pies.

If the price of a magazine is $4 each, what is the maximum number of magazines she could buy in a week?

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If the price of a pie is $12, what is the maximum number of pies she could buy in a week?

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Draw Marie’s budget constraint with pies on the horizontal axis and magazines on the vertical axis. What is the slope of the budget constraint?

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What is Marie’s opportunity cost of purchasing a pie?

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Bureau of Labor Statistics, U.S. Department of Labor. 2015. “Median Weekly Earnings by Educational Attainment in 2014.” Accessed March 27, 2015. http://www.bls.gov/opub/ted/2015/median-weekly-earnings-by-education-gender-race-and-ethnicity-in-2014.htm.

Robbins, Lionel. An Essay on the Nature and Significance of Economic Science . London: Macmillan. 1932.

United States Department of Transportation. “Total Passengers on U.S Airlines and Foreign Airlines U.S. Flights Increased 1.3% in 2012 from 2011.” Accessed October 2013. http://www.rita.dot.gov/bts/press_releases/bts016_13

Questions & Answers

important of enocomic
Adu Reply
what is division of labour
Dennis Reply
division of labour can be defined as the separation of task to individuals in any economic system to specialize on it.
what is demand curve
Victoria Reply
demand curve is a downward sloping economic graph that shows the relationship between the price of product and the quantity of the product demanded.
What is demand
Frank Reply
It refers to the quantity of a commodity purchased in the market at a price and at a point of time.
refers to amount of commodities a consumer is willing and able to buy at particular price within a period of time
It is the ability and willingness a customer buys a product or service at a particular price, place and time while other things remaining constant or the same
In which case is opportunity cost is zero
Francis Reply
where no alternative is available
who is the father of economic
Omar Reply
Adam Smith
Adam Smith
Adam smith
Adam Smith
What is monopoly
Mauthoor Reply
it an economic situation where one individual controls the essential commodities or value product for maximum profit
monopoly is a market situation in which there is only one producer of a good or service which has no close substitutes
is where only one person is solely the price taker
what is Monopoly
Dauda Reply
The word Monopoly is a Latin word. it is the combination of two words-Mono means single and Poly means seller. thus Monopoly means single seller. but this is not the full meaning of Monopoly. Monopoly must produce a product which does not have close substitute in the market.
Monopoly is define as a firm in an industry with very high barriers to entry.
If close substitute is available, Monopoly will be a king without a crown.
what does it array
Cbdishakur Reply
what are the differences between monopoly and.oligopoly
Onome Reply
what are the difference between monopoly and oligopoly
The deference between Monopoly and Oligopoly: Monopoly means:A single-firm-Industry producing and selling a product having no close business and Oligopoly means:A market structure where a few sellers compete with each other and each controls a significant portion of market .
so that the price-output policy one affects the other.
what are difference between physical policy and monotory policy
what is economic
Emakpor Reply
what is economic
the word economic was derived from the Greek word oikos (a house)and mein(to manage) which in effect meant managing a household with the limited funds available 🙂.
good excample about scarsity
An Enquiry into the nature and causes of wealth Nations, this book clearly defined what economic is🙂🙂🙏🙏 thank you...
good example about scarcity: money,time, energy, human or natural resources. Scarcity of resources implies that there supply is very much limited in relation to demand.
equilibrium is a situation in which economic forces such as demand and supply are balanced and in the absence of external influences,the value of economic variables will not change
Onome Reply
marginal cost and marginal revenue is equilibrium .
what is equilibrium
Rodrice Reply
policy prescriptions for unemployment
Jeslyne Reply
Am working on it
what are the factors effecting demand sedule
Kalimu Reply
we should talk about more important topics, you can search it on Google n u will find your answer we should try to focus on how we can improve our society using economics
so good night
Why do people buy more grapes in December than in July?
because at time know money

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Source:  OpenStax, Principles of economics. OpenStax CNX. Sep 19, 2014 Download for free at http://legacy.cnx.org/content/col11613/1.11
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