Opportunity Cost | 机会成本

📚 Opportunity Cost | 机会成本

Opportunity cost is one of the most fundamental concepts in economics. It refers to the next best alternative that is given up when a choice is made.

机会成本是经济学中最基本的概念之一。它指的是在做出选择时，所放弃的下一个最佳替代选项。

Because resources are scarce, every choice involves a trade-off. When you spend money on one thing, you cannot spend that same money on something else. The value of the alternative you sacrifice is your opportunity cost.

由于资源是稀缺的，每一项选择都涉及取舍。当你把钱花在一件事上，你就不能把这笔钱花在另一件事上。你所牺牲的那个替代选择的价值，就是你的机会成本。

1. Scarcity Forces Choice | 稀缺迫使人们作出选择

Scarcity means that human wants are infinite while resources are finite. In Cambridge IGCSE Economics, you are expected to understand that scarcity is the basic economic problem that affects individuals, firms and governments.

稀缺性意味着人类的欲望是无限的，而资源是有限的。在剑桥 IGCSE 经济学中，你需要理解稀缺性是一个影响个人、企业和政府的基本经济问题。

Because resources such as land, labour, capital and enterprise cannot produce all goods and services that people want, we must choose which wants to satisfy first. Every time we choose one option, we lose the chance to enjoy another option.

由于土地、劳动、资本和企业家才能等资源无法生产出人们想要的所有商品和服务，我们必须选择先满足哪些欲望。每当我们选择一个选项，我们就失去了享受另一个选项的机会。

Scarcity is the gap between unlimited wants and limited resources.

稀缺性是无限欲望与有限资源之间的差距。
Choice arises from scarcity.

选择源于稀缺性。
Opportunity cost measures the cost of the choice in terms of the next best alternative foregone.

机会成本以所放弃的下一个最佳替代方案来衡量选择的成本。

2. Definition of Opportunity Cost | 机会成本的定义

The formal definition used in Cambridge IGCSE Economics is: opportunity cost is the next best alternative given up when an economic decision is made.

剑桥 IGCSE 经济学使用的正式定义是：机会成本是作出经济决策时被放弃的下一个最佳替代选择。

Notice that opportunity cost is not the total value of all alternatives that are sacrificed. It is only the value of the next best alternative. If you choose to study economics rather than studying history or geography, your opportunity cost is only the value of studying the subject you preferred among the alternatives not chosen.

请注意，机会成本并不是所有被放弃替代选择的总体价值。它只是下一个最佳替代选择的价值。如果你选择学习经济学，而不是学习历史或地理，你的机会成本只是未被选择选项中你最偏好的那个学科的价值。

Opportunity cost = value of the next best alternative foregone

机会成本 = 所放弃的下一个最佳替代选择的价值

3. Consumer Example: Spending £10 | 消费者例子：花费 10 英镑

Imagine a student has £10 and wants to buy either a T-shirt or a cinema ticket. The T-shirt costs £10 and the cinema ticket also costs £10. If the student chooses the T-shirt, the opportunity cost is the satisfaction that would have been gained from watching the film.

想象一名学生有 10 英镑，想买一件 T 恤或一张电影票。T 恤售价为 10 英镑，电影票也是 10 英镑。如果学生选择 T 恤，机会成本就是看电影本可以带来的满足感。

The money cost of the T-shirt is £10, but the true economic cost includes the lost enjoyment from the cinema. This distinction is important because money cost and opportunity cost are not always the same.

T 恤的货币成本是 10 英镑，但真正的经济成本包括失去的电影享受。这一区别很重要，因为货币成本和机会成本并不总是相同的。

If the student did not plan to go to the cinema anyway, and the next best alternative was buying a book for £10, then the opportunity cost becomes the value of the book. The opportunity cost depends on what the decision maker would have done next.

如果学生本来也没打算去看电影，而下一个最佳替代选择是花 10 英镑买一本书，那么机会成本就变成了那本书的价值。机会成本取决于决策者本来接下来会做什么。

4. Producer Opportunity Cost | 生产者的机会成本

Firms also face opportunity costs. A factory that can produce only one product at a time must decide between producing cars or producing bicycles. If it chooses to produce one car, the opportunity cost is the number of bicycles it could have produced instead.

企业也面临着机会成本。一家每次只能生产一种产品的工厂必须决定是生产汽车还是生产自行车。如果它选择生产一辆汽车，机会成本就是它本来可以生产出的自行车数量。

Similarly, a farmer who uses one field to grow wheat cannot use that same field to grow corn. The opportunity cost of wheat is the corn that could have been grown.

同样，一个农民用一块地种小麦，就不能用同一块地种玉米。种小麦的机会成本就是本来可以种出的玉米。

Producers must consider the trade-off between different goods.

生产者必须考虑不同商品之间的取舍。
Resources used for one purpose cannot be used for another purpose at the same time.

用于某一用途的资源不能同时用于另一用途。
Efficient production means minimising waste, which includes avoiding high opportunity cost decisions.

有效生产意味着减少浪费，其中包括避免作出机会成本较高的决策。

5. Government and Society | 政府与社会

Governments face opportunity cost too. If the government spends more money on building hospitals, it may have less money to spend on building schools or roads. The opportunity cost of a new hospital is the value of the new school or road that is given up.

政府也面临机会成本。如果政府把更多资金用于建设医院，它可能就没有那么多资金来建设学校或道路。新医院的机会成本就是被放弃的新学校或新道路的价值。

This idea is closely related to the production possibility frontier, which illustrates the maximum possible output combinations of two goods that an economy can produce using all its resources efficiently.

这个想法与生产可能性边界密切相关，生产可能性边界说明了一个经济体在有效利用其全部资源的情况下，两种商品可能达到的最大产量组合。

When the government decides to spend on defence rather than health care, the true cost is not just the money spent, but the health services that were sacrificed. Economists care about this cost because it measures the real sacrifice for society.

当政府决定在国防而不是医疗上支出时，真正的成本不仅仅是花掉的钱，还有被牺牲的医疗服务。经济学家关注这一成本，因为它衡量了社会真正的牺牲。

6. Production Possibility Curve | 生产可能性曲线

The production possibility curve (PPC) is a diagram that shows the maximum combinations of two goods an economy can produce when all resources are fully and efficiently used.

生产可能性曲线是一个图形，它显示了一个经济体内在全部资源得到充分有效利用时，两种商品可以达到的最大组合。

A common Cambridge question asks you to interpret a PPC. Points on the curve represent efficient production, points inside the curve represent inefficiency, and points outside the curve are unattainable with current resources.

一个常见的剑桥考题要求你解释生产可能性曲线。曲线上的点表示有效生产，曲线内的点表示低效率，而曲线外的点在当前资源条件下是无法达到的。

Position	Meaning
On the curve	All resources are used efficiently; output is maximised.
Inside the curve	Some resources are unemployed or used inefficiently.
Outside the curve	Unattainable with current resources and technology.
Moving along the curve	Involves an opportunity cost; more of one good means less of the other.

位置含义表格：曲线上、曲线内、曲线外、沿曲线移动分别代表有效、低效、不可达和机会成本。

7. Opportunity Cost and the Shape of the PPC | 机会成本与生产可能性曲线的形状

The shape of the PPC depends on whether opportunity cost is constant or increasing. In Cambridge IGCSE Economics, you should know the difference between a straight-line PPC and a bowed-outward PPC.

生产可能性曲线的形状取决于机会成本是不变还是递增。在剑桥 IGCSE 经济学中，你应该知道直线型生产可能性曲线和向外弯曲的生产可能性曲线之间的区别。

A straight-line PPC means that the opportunity cost of producing more of one good is constant. This happens when resources are equally suitable for producing both goods.

直线型生产可能性曲线意味着生产更多一种商品的机会成本是不变的。当资源同样适用于生产两种商品时，就会出现这种情况。

A bowed-outward PPC means that opportunity cost increases as more of one good is produced. This occurs because resources are not equally efficient in producing all goods. For example, some workers are better at farming, while others are better at making machines.

向外弯曲的生产可能性曲线意味着随着一种商品产量的增加，机会成本也在增加。这是因为资源在生产所有商品时并非同等有效。例如，有些工人更擅长务农，而另一些工人更擅长制造机器。

Increasing opportunity cost → concave (bowed-outward) PPC

机会成本递增 → 凹向原点（向外弯曲）的生产可能性曲线

8. Opportunity Cost in Everyday Decisions | 日常决策中的机会成本

Opportunity cost applies to everyone, not just firms and governments. When you choose to sleep an extra hour instead of studying, the opportunity cost is the higher grade you might have earned.

机会成本适用于每个人，不仅仅是企业和政府。当你选择多睡一小时而不是学习时，机会成本就是你本可以获得的更高分数。

Attending university has a money cost, such as tuition fees, but it also has an opportunity cost. While studying full time, a student gives up the wages they could have earned from a full-time job. This is often called the indirect cost of education.

上大学有货币成本，例如学费，但它也有机会成本。在全日制学习期间，学生放弃了他们本可以从全职工作中赚到的工资。这通常被称为教育的间接成本。

Leisure time has an opportunity cost of lost earnings.

闲暇时间的机会成本是失去的收入。
Spending on luxury goods has an opportunity cost of reduced savings.

在奢侈品上花钱的机会成本是储蓄减少。
Using a road for one type of transport prevents another type using the same road.

一条路被一种交通工具使用，就不能同时被另一种交通工具使用。

9. Sunk Costs vs Opportunity Cost | 沉没成本与机会成本

Sunk costs are costs that have already been paid and cannot be recovered. Sunk costs should not influence future decisions because they are unaffected by the choice being made.

沉没成本是已经支付且无法收回的成本。沉没成本不应该影响未来的决策，因为它们不受当前选择的影响。

For example, if a firm has already spent £1,000 on advertising and the campaign is not working, the £1,000 is a sunk cost. The firm should decide whether to continue based on the future benefits and the next best use of the money, not on the money already spent.

例如，如果一家公司已经在广告上花费了 1,000 英镑，而广告活动没有效果，这 1,000 英镑就是沉没成本。公司应该根据未来的收益和这笔钱的下一个最佳用途来决定是否继续，而不是基于已经花掉的钱。

Opportunity cost always involves the future, because it looks at what you could do instead. Sunk costs look at the past, so they are irrelevant to rational economic decisions.

机会成本始终涉及未来，因为它关注的是你本来可以做些什么。沉没成本着眼于过去，因此它们与理性经济决策无关。

10. Common Mistakes in Exams | 考试中的常见错误

Students often confuse opportunity cost with money cost. In an exam, if you write that opportunity cost is ‘the amount of money paid’, you will not earn the mark.

学生经常把机会成本和货币成本混淆。在考试中，如果你写机会成本是“支付的金额”，你将无法得分。

Another common error is to state that opportunity cost is ‘the alternative not chosen’. The correct phrase is the next best alternative foregone. There may be many alternatives, but only the highest-valued one is counted.

另一个常见错误是写机会成本是“没有被选择的替代选项”。正确的说法是被放弃的下一个最佳替代选择。可能有许多替代选项，但只有价值最高的那一个才被计入。

Always use the phrase ‘next best alternative foregone’ in definitions.

在定义中始终使用“所放弃的下一个最佳替代选择”这一表达。
Use examples from consumers, producers and governments.

举出消费者、生产者和政府的例子。
When a question shows a PPC, describe the trade-off and state the opportunity cost clearly.

当题目给出生产可能性曲线时，描述取舍并清楚说明机会成本。
Do not say ‘all alternatives’; say ‘the next best alternative’.

不要说“所有替代选择”；要说“下一个最佳替代选择”。

11. Why Opportunity Cost Matters in Economics | 为什么机会成本在经济学中很重要

Opportunity cost is at the heart of economic thinking. It reminds us that every choice has a cost, even when no money is directly paid.

机会成本是经济思维的核心。它提醒我们，每项选择都有代价，即使没有直接支付金钱。

Economists use opportunity cost to evaluate the real cost of government projects, business investments and personal decisions. When comparing policies, economists do not only ask how much money they cost, but what else could have been done with that money.

经济学家利用机会成本来评估政府项目、企业投资和个人决策的真实成本。在比较不同政策时，经济学家不仅会问它们花费多少钱，还会问这笔钱本可以用来做些什么。

This concept also explains why countries specialise and trade. If a country has a lower opportunity cost in producing a good, it holds a comparative advantage, and trade can make both countries better off.

这个概念也解释了为什么国家会进行专业化和国际贸易。如果一个国家在生产某种商品时机会成本较低，它就拥有比较优势，而贸易可以使两国都变得更好。

12. Summary of Key Points | 要点总结

Opportunity cost is the value of the next best alternative given up when a choice is made. It applies to consumers, producers and governments.

机会成本是作出选择时被放弃的下一个最佳替代选择的价值。它适用于消费者、生产者和政府。

There is no such thing as a free lunch because every use of a scarce resource involves an opportunity cost. The PPC is a powerful tool for showing opportunity cost visually, and increasing opportunity cost gives the curve its bowed-outward shape.

天下没有免费的午餐，因为对稀缺资源的每一次使用都涉及机会成本。生产可能性曲线是一个直观展示机会成本的强大工具，而递增的机会成本使曲线呈现向外弯曲的形状。

Remember to avoid confusing opportunity cost with money cost, and always focus on the highest-valued alternative not chosen.

记住不要将机会成本与货币成本混淆，并且始终关注未选择选项中价值最高的那一个。

Published by TutorHao | Economics Revision Series | aleveler.com

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Opportunity Cost | 机会成本