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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

why is the marginal curve u shaped
jake Reply
which of marginal curve?
marginal cost curve
what is demand function
uju Reply
demand function is the mathematical representation of price and quantity demanded of goods and services at various prices at a given time .
Demand function is an equation which shows the mathematical relationship between the quantity demanded of a good and the values of the various determinants of demand.
why would division of labour without trade not work
Frederick Reply
as far there is an output as a goal... trade can't be exempted... because the sole reason for division of labour is for an effective and efficient output or outcome.. with such exchange trade has taken place. .
Please what is paradox of value
what is the features of monopoly market? how it is different from monopolistic market?
how does scarcity described as the efficient byway to allocate resources in a free market?
God Reply
scarcity gives or births a rational thinking to an individual or state economy in the distribution of revenue or income to the right channels of their ends... assuming the market has the features of a free market (free entry and exit, close substitutes, market price control etc)
wath is the meaning the macro economics
Jimcaale Reply
What is the way out of Scarcity
a state referenced economic study, the manner or behavioural pattern of a state choice in making economic decisions in satisfying their ends
Thanks brother
what is macro economics
is the study of a national economy as a whole
what is micro economics
micro is not the study of the entire economy as a whole. that is macro economics.
micro focuses more on decisions that individuals and firms make but also uses examples of countries regarding production.
I think is why some people get mixed up.
thanks a lot
yes ,I think that is right
how would you use budget constraints to explain trade off?
what is the difference between wants and needs as in economics
wants may be unlimited but needs have the limit on the base of effort to pay.
who n who is d founder of economic. txn
adam smith is the founder of modern economics but previous than we can read ununified economic thought of kautilya and others.
thanx very much
In economic, the idea of survival is real, meaning someone would die with out the needs being met.This includes things like food, water, and shelter. A wants, in economic, is one step up in the order from needs and is simply something that people desire to have, that they may, or may not, obtain.
when total utility is constant, marginal utility do what?
rasheed Reply
Why is it that whenever I ask a question no one hears me out
This is deals with only 1producer 1producer 1consumer
Motasay Reply
thanks for you answer
With two buyers n sellers
nothing only I study
still oligopoly That is when there is a limited buyer and seller in the industry. There are no perfectly elastic market entry, that is for both the price taker and the seller
thanks for your advice
welcomed bro
we can ask our doubt also isn't
Yea you can as well
Like "beauty opportunity cost lies in the eyes of the beholder"discuss with practical examples
Criticism of scarcity definition
No Reply
life is all about scarcity. there is a big reason behind that
tell me the whole
as we are Muslims
so what
we believe that our Allah. the God of Universe is Examining each and every one on the planet this Scarcity. the only place there is no scarcity is Aakhiro Doomsday
i want Explanation ?
You have came back our book of Quran
Make some of our basic needs not available. For example like if we need a particular drugs to cure a virus ohh disease because if the scarcity of it it may lead to death
what men gdb
Jimcaale Reply
with men government demand price
how to draw demand curve
Michael Reply
What are the distinction between trade off and opportunity cost?
Eric Reply
what is monopoly
Mary Reply
What are the sources of monopoly
Sources of Monopoly Power Monopoly power is influenced by the following factors: Barriers to entry Number of competitors Advertising Degree of product differentiation The larger and more expensive the barriers to entry the greater the monopoly power The smaller the number of competitors in th
monopoly occurs when specific enterprise supplies goods and controls the market.
i think the sources of monopoly are barriers to enrty and product differentiation.
Monopoly is a market structure characterized by a single seller, selling a unique product in the market in which s/he faces no competition, as s/he is the sole seller of goods with no close substitute.
Monopoly is a market structure where the production of goods and services coupled with price determination of such commodities are left in the hands of a sole producer. Such factors are; Perfectly inelastic competition, High market barricade, High cost of raw materials,
what is price discrimination monopoly
sandra Reply
Charging different sets of consumers different prirces for the same good or service, for reasons not involved in cost of production. There are 3 degrees of price discrimination.
what are the 3 degree
What up guys
what are four sources of monopoly
dora Reply
examples of what cause demand and supply to shift to the left.
Verte Reply
how are you
are you fine
Why is there a trade off between inflation and employment? Give a situation to clear it up please

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