📚 Year 8 CIE Economics: Case Study Skills in Action | 八年级CIE经济：案例分析实战演练
In Year 8 CIE Economics, case studies are more than just stories – they are your bridge between textbook theories and the real world. A well‑structured case study asks you to identify economic concepts, apply them to specific situations and make reasoned judgements. This article provides a hands‑on practical workout, guiding you through multiple case scenarios and showing you step by step how to think like an economist.
在八年级CIE经济课程中，案例分析不仅仅是讲故事——它是连接课本理论与真实世界的桥梁。一个结构清晰的案例分析要求你识别经济概念、将其应用到具体情境中并做出合理的判断。本文提供一次动手实战演练，带你走进多个案例场景，并逐步展示如何像经济学家一样思考。
1. What Is an Economic Case Study? | 什么是经济案例分析？
An economic case study is a short description of a real or realistic situation that involves a choice, a market or a policy decision. Your job is to unpack the information, spot the underlying economic problem and use concepts like scarcity, opportunity cost, supply and demand to explain what is happening and to suggest possible outcomes.
经济案例分析是对一个真实或贴近现实的场景的简短描述，其中涉及选择、市场或政策决定。你的任务是拆解信息，找出背后的经济问题，并用稀缺性、机会成本、供给和需求等概念来解释正在发生的事情并提出可能的结果。
Every case, no matter how simple, contains four key elements: a decision maker, limited resources, constraints and a 'what next' question. Learning to extract these elements is the first skill we will practise.
每个案例，无论多简单，都包含四个关键要素：决策者、有限的资源、约束条件和一个“接下来怎么办”的问题。学会提取这些要素是我们将要练习的第一项技能。
2. How to Break Down Case Information | 如何拆解案例信息
Before you look for answers, you must organise the information. Start by reading the case twice. On the first read, underline the names of the people, firms or governments involved and circle any numbers, prices or quantities. On the second read, note the central problem – is it about what to produce, how to produce or for whom to produce? Write down two economic keywords that fit the scene, such as 'scarcity', 'opportunity cost', 'demand', 'substitute' or 'incentive'.
在寻找答案之前，你必须整理信息。首先读两遍案例。第一遍阅读时，划出涉及的人物、企业或政府名称，并圈出所有数字、价格或数量。第二遍阅读时，注意核心问题——它是关于生产什么、如何生产还是为谁生产？写下两个符合场景的经济关键词，例如“稀缺性”“机会成本”“需求”“替代品”或“激励”。
Next, separate facts from opinions. Facts are objective statements like 'The price of flour rose by 15%'. Opinions are subjective, such as 'The manager thought customers would not mind'. Only facts can be used to build your economic reasoning; opinions may help you identify motives but must be treated with caution.
接下来将事实与观点分开。事实是客观陈述，比如“面粉价格上涨了15%”。观点是主观的，比如“经理认为顾客不会介意”。只有事实才能用来构建你的经济推理；观点可能有助于识别动机，但必须谨慎对待。
3. Case Practice 1: The Free Cinema Ticket | 案例实战一：免费电影票的选择
Scenario: Your friend gives you a free cinema ticket for tonight. The film is one you really want to see. However, you had planned to spend the evening working at your family's shop, where you can earn £25. You also have a geography revision session scheduled with a classmate. If you go to the cinema, you will miss both the work and the revision.
场景：你的朋友送你一张今晚的免费电影票，电影是你非常想看的。然而，你原本计划晚上在自家店里帮忙，可以赚到25英镑。你还和一个同学约好了一起复习地理。如果你去看电影，就会错过工作和复习。
Questions for you to consider:
请你思考以下问题：
1. What is the real cost of using the free ticket?
2. If you value the film at £30 worth of enjoyment, does it make economic sense to go?
3. How would your answer change if your classmate were relying on you to pass the exam?
1. 使用这张免费电影票的实际成本是什么？
2. 如果你认为这场电影带来的享受价值30英镑，从经济角度看，去看电影是否合理？
3. 如果你的同学靠你帮助才能通过考试，你的答案会如何变化？
4. Case 1 Answer and Analysis | 案例一答案与解析
The free ticket has a monetary price of zero, but economists think in terms of opportunity cost – the value of the next best alternative given up. Here, the next best alternative is either earning £25 or attending the revision session, whichever you value more. If you would have chosen to work, the opportunity cost is £25 plus the lost revision time, which might have an additional future value.
免费电影票的货币价格为零，但经济学家考虑的是机会成本——即所放弃的次优选择的价值。这里，次优选择要么是赚25英镑，要么是参加复习课，取决于你哪个价值更高。如果你本来会选择工作，机会成本就是25英镑加上失去的复习时间，后者可能还有额外的未来价值。
If you value the film at £30 and your opportunity cost is £25, the net gain is £5, so going would be rational. However, if the revision session is essential for a passing grade and you value that at £50, the opportunity cost becomes £50, making the cinema trip a poor choice economically.
如果你认为电影价值30英镑，而机会成本是25英镑，净收益为5英镑，那么去看电影是理性的。然而，如果复习课对于及格至关重要且你将其估值为50英镑，机会成本就变成了50英镑，这样去看电影就是一个不经济的选择。
The key lesson: 'free' rarely means zero cost. Every choice sacrifices something, and opportunity cost helps you compare unlike alternatives – money, time and even friendship.
关键启示：“免费”极少意味着零成本。每一次选择都牺牲了某种东西，而机会成本帮助你在金钱、时间甚至友谊等不同选项之间进行比较。
5. Case Practice 2: Pizza Demand in the School Canteen | 案例实战二：学校食堂的披萨需求
Scenario: The school canteen sells Margherita pizza at £2.50 per slice. On average, 120 slices are bought each day. The canteen manager decides to raise the price to £3.00. After one week, daily pizza sales drop to 85 slices. Meanwhile, the sales of pasta pots, priced at £2.20, increase from 70 to 95 units per day.
场景：学校食堂以每片2.50英镑的价格出售玛格丽特披萨，平均每天售出120片。食堂经理决定将价格提高到3.00英镑。一周后，披萨日销量降至85片。与此同时，定价2.20英镑的意面杯日销量从70份上升到95份。
Questions for you to consider:
请你思考以下问题：
1. Calculate the total daily revenue from pizza before and after the price change. Did revenue rise or fall?
2. Why did pizza sales fall? Relate your answer to the law of demand.
3. What is the economic relationship between pizza and pasta pots in this example?
1. 计算价格变动前后披萨的每日总收入。收入是上升了还是下降了？
2. 为什么披萨销量下降？请结合需求定律回答。
3. 在这个例子中，披萨和意面杯之间是什么经济关系？
6. Case 2 Answer and Analysis | 案例二答案与解析
Before the price rise, daily revenue from pizza was 120 × £2.50 = £300. After the rise, revenue became 85 × £3.00 = £255. So the price increase led to a £5 drop in total revenue. This shows that demand for pizza in this canteen is price elastic – n quantity demanded was larger than the percentage rise in price, causing revenue to fall.
涨价前，披萨的日收入为120 × 2.50英镑 = 300英镑。涨价后，收入变为85 × 3.00英镑 = 255英镑。因此，价格上涨导致总收入下降了45英镑。这表明食堂披萨的需求是富有价格弹性的——需求量的下降百分比大于价格上涨的百分比，从而导致收入下降。
Pizza sales fell because the law of demand states that, ceteris paribus, as price rises, quantity demanded decreases. Students likely switched to the more affordable pasta pot, which became relatively cheaper. Pasta pots are a substitute for pizza; when the price of one rises, demand for the substitute increases, which is exactly what the data show.
披萨销量下降是因为需求定律指出，在其他条件不变的情况下，价格上涨则需求量下降。学生们可能转向了更实惠的意面杯，后者变得相对便宜。意面杯是披萨的替代品；当一种商品的价格上升时，对其替代品的需求就会增加，数据恰好体现了这一点。
7. Case Practice 3: Supply Shock at a Lemonade Stand | 案例实战三：柠檬水摊的供给冲击
Scenario: Tom runs a small lemonade stand every Saturday. His usual recipe requires 8 lemons, 200 g of sugar and 3 litres of water to make 20 cups, which he sells for £0.80 each. One week, bad weather in the lemon‑growing region causes the price of lemons to double from £0.25 to £0.50 each. Tom cannot find a cheaper supplier and his other costs remain unchanged.
场景：汤姆每周六经营一个小柠檬水摊。他通常的配方需要8个柠檬、200克糖和3升水，可制作20杯，每杯售价0.80英镑。有一周，柠檬产区的恶劣天气导致柠檬价格从每个0.25英镑翻倍至0.50英镑。汤姆找不到更便宜的供应商，其他成本保持不变。
Questions for you to consider:
请你思考以下问题：
1. Calculate Tom's total cost and profit per 20 cups before the lemon price rise.
2. After the rise, what happens to his cost per cup? What are his options if he wants to maintain his profit?
3. How is this an example of a supply shock? Draw a supply‑side conclusion.
1. 计算柠檬价格上涨前汤姆每20杯的总成本和利润。
2. 价格上涨后，他的每杯成本发生了什么变化？如果他想维持利润，有哪些选择？
3. 这如何体现供给冲击？请得出一个供给侧的结论。
8. Case 3 Answer and Analysis | 案例三答案与解析
Before the shock, lemon cost per 20 cups was 8 × £0.25 = £2.00. Sugar and water cost, say, £1.20 in total, so total cost = £3.20. Revenue from 20 cups is 20 × £0.80 = £16.00, giving a profit of £12.80. After the price doubles, lemon cost becomes 8 × £0.50 = £4.00, so total cost rises to £5.20. Profit falls to £10.80, a drop of £2.00.
在冲击前，20杯柠檬水的柠檬成本为8 × 0.25英镑 = 2.00英镑。糖和水的成本假如合计为1.20英镑，则总成本为3.20英镑。20杯的收入为20 × 0.80英镑 = 16.00英镑，利润为12.80英镑。柠檬价格翻倍后，柠檬成本变为8 × 0.50英镑 = 4.00英镑，总成本升至5.20英镑。利润降至10.80英镑，减少了2.00英镑。
Tom now faces a supply shock – a sudden increase in the cost of a key input. To restore his profit, he could raise his selling price, use fewer lemons (which might lower quality), switch to a powdered lemon mix or absorb the loss. Each option has trade‑offs; for example, raising the price might reduce the quantity demanded, as seen in the pizza case.
汤姆现在面临供给冲击——关键投入品成本突然上升。要恢复利润，他可以提高售价、减少柠檬用量（可能降低质量）、改用柠檬粉或自己承担损失。每种选择都有权衡；例如，涨价可能会降低需求量，正如披萨案例所示。
This case illustrates that when the cost of production rises, the supply curve shifts to the left, leading to a lower quantity supplied at any given price unless the firm can pass on the cost. For Tom, the shock means he may supply fewer cups unless demand is very inelastic.
这个案例说明，当生产成本上升时，供给曲线向左移动，除非企业能将成本转嫁出去，否则在任何给定价格下供给量都会减少。对汤姆而言，这次冲击意味着除非需求非常缺乏弹性，否则他可能会减少供应量。
9. Case Practice 4: Government Subsidy for Bicycles | 案例实战四：政府补贴自行车
Scenario: The government is concerned about air pollution and wants more people to cycle to work. It introduces a £50 subsidy paid directly to bicycle manufacturers for every bicycle produced. Before the subsidy, the equilibrium price of a basic urban bicycle was £240, with 12 000 bicycles sold per month. After the subsidy, the price falls to £210 and quantity sold rises to 16 000 per month.
场景：政府担忧空气污染，希望更多人骑车上班。它推出了一项补贴政策，每生产一辆自行车，政府就向制造商支付50英镑。补贴前，一辆基础款城市自行车的均衡价格为240英镑，月销量为12 000辆。补贴后，价格降至210英镑，月销量升至16 000辆。
Questions for you to consider:
请你思考以下问题：
1. Explain why the subsidy causes the supply curve to shift. In which direction does it shift?
2. How does the subsidy affect the market for bicycles? Mention both consumers and producers.
3. What might happen to the demand for bus travel as a consequence? Why?
1. 解释为什么补贴会导致供给曲线移动。它向哪个方向移动？
2. 补贴如何影响自行车市场？请同时提及消费者和生产者。
3. 这一变化可能对公交车出行的需求产生什么影响？为什么？
10. Case 4 Answer and Analysis | 案例四答案与解析
A £50 subsidy per unit reduces the cost of production for manufacturers. This makes it profitable for firms to supply more at every price level, so the supply curve shifts to the right. On a diagram, the new supply line sits below the original one, intersecting the demand curve at a lower price and a higher quantity – exactly what the data show.
每辆50英镑的补贴降低了制造商的生产成本，这使得在每个价格水平上企业都愿意供应更多，因此供给曲线向右移动。在图上，新的供给线位于原供给线的下方，与需求曲线相交于一个更低的价格和更高的数量——数据恰好印证了这一点。
Consumers benefit from a lower price (£210 instead of £240) and buy more bicycles. Producers receive the market price plus the £50 subsidy, so their effective selling price is £260, which is higher than the pre‑subsidy equilibrium price. Both sides gain: consumer surplus and producer surplus both increase, though part of the subsidy is paid for by taxpayers.
消费者受益于更低的价格（210英镑而非240英镑）并购买了更多的自行车。生产者获得市场价格外加50英镑补贴，因此他们实际获得的售价为260英镑，高于补贴前的均衡价格。双方都受益：消费者剩余和生产者剩余都增加了，尽管部分补贴由纳税人承担。
Because cycling becomes cheaper, some people will switch from buses to bicycles. This makes bus travel a substitute for cycling. As the demand for bicycles rises, the demand for bus journeys is likely to fall, shifting the demand curve for bus travel to the left, which could reduce both the quantity and price of bus tickets in the long run.
由于骑车变得更便宜，一些人会从公交车转向自行车，这使得公交车出行成为骑车的替代品。随着自行车需求上升，公交车出行的需求可能会下降，导致公交车出行的需求曲线向左移动，长期来看可能降低公交车票的销量和价格。
11. Common Mistakes and Improvement Tips | 常见错误与改进技巧
Many Year 8 students lose marks by describing what happens without using economic terminology. Avoid simply retelling the story. Instead, always link events to a concept: say 'this is an example of opportunity cost' or 'this shows the law of demand'. Use the phrase 'ceteris paribus' when you assume other factors remain unchanged.
许多八年级学生因只是描述发生了什么而没有使用经济术语而失分。避免仅仅复述故事。相反，始终将事件与概念联系起来：说出“这是机会成本的一个例子”或“这显示了需求定律”。当你假设其他因素不变时，使用“其他条件不变”这一短语。
A second common error is ignoring the numbers. Calculations matter: a quick revenue or profit calculation often reveals whether a decision is sensible. Always show your working, even if the arithmetic is simple. Data tables and simple percentage changes make your analysis stronger and easier to follow.
第二个常见错误是忽略数字。计算很重要：一个快速的收入或利润计算常常能揭示一项决策是否合理。始终展示你的演算过程，即使算术很简单。数据表格和简单的百分比变化能让你的分析更有力度、更易理解。
12. Summary: Building Your Case Study Toolkit | 总结：打造你的案例分析工具箱
By working through these four practical cases, you have seen how the same core economic ideas – scarcity, opportunity cost, demand and supply – appear in very different everyday situations. The steps you practised (reading for keywords, identifying the decision maker, linking facts to concepts and using calculations to support your reasoning) form a repeatable toolkit for any CIE case study question.
通过这四次实战案例，你看到了相同的核心经济思想——稀缺性、机会成本、需求和供给——如何出现在完全不同的日常情境中。你练习的步骤（寻找关键词、识别决策者、将事实与概念联系起来以及用计算支持推理）构成了一套可重复使用的工具箱，适用于任何CIE案例分析题。
Remember that a strong answer always states the concept, applies it to the specific details of the case and then evaluates possible outcomes or trade‑offs. Practise with more scenarios from your textbook or from the news, and soon case studies will feel like puzzles you are well equipped to solve.
请记住，一个出色的答案总是先陈述概念，然后将其应用于案例的具体细节，最后评估可能的结果或权衡。请用你课本或新闻中的更多场景进行练习，很快案例分析就会变成你完全有能力解决的谜题。
Published by TutorHao | Economics Revision Series | aleveler.com
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