📚 Year 12 WJEC Economics: Case Study Practice Drill | Year 12 WJEC 经济：案例分析实战演练
A significant portion of your WJEC AS Economics assessment relies on your ability to apply theoretical knowledge to real-world case studies. This skill goes beyond memorising definitions; it requires interpreting extracts, graphs and data, then constructing clear, analytical arguments under timed conditions. This article provides a structured drill to help you master the case study approach for Unit 1 and Unit 2.
WJEC AS 经济考试中，有相当一部分题目考查你将理论知识应用于真实案例的能力。这项技能不只是背诵定义，更需要在限时条件下解读摘录、图表和数据，然后构建清晰、有分析性的论证。本文为你提供一套结构化实战演练，帮助你掌握第一单元和第二单元的案例分析答题方法。
1. Understanding the Case Study Format | 理解案例分析题的格式
WJEC case study questions typically present a short extract describing an economic situation, often accompanied by a table or graph. The questions that follow test knowledge, application, analysis and evaluation.
WJEC 的案例分析题通常会提供一段描述某一经济情况的简短摘录，并常常配有一张表格或图表。后续的问题会考查知识、应用、分析和评价能力。
For Unit 1 (Markets in Action), you can expect topics such as shifts in demand and supply, price elasticity, market failure or government intervention. Unit 2 (Macroeconomic Theory) case studies may focus on GDP, inflation, unemployment, fiscal or monetary policy.
在第一单元（市场行为）中，你可能会遇到需求与供给的变动、价格弹性、市场失灵或政府干预等主题。第二单元（宏观经济理论）的案例可能聚焦于国内生产总值、通货膨胀、失业、财政政策或货币政策。
Always identify the command words: ‘Explain’, ‘Analyse’, ‘Evaluate’ or ‘Discuss’. Each demands a different depth of response. For example, ‘Analyse’ requires step-by-step reasoning using the case evidence, whereas ‘Evaluate’ expects you to weigh up arguments and make a supported judgement.
一定要识别出指令词：“解释”、“分析”、“评价”或“讨论”。每个词要求的答题深度不同。例如，“分析”需要利用案例证据逐步推理，而“评价”则要求你权衡论点并作出有依据的判断。
2. Extracting Key Economic Concepts | 提取关键经济概念
Before writing, underline or highlight every piece of economic terminology in the extract. Words like ‘subsidy’, ‘external cost’, ‘derived demand’, ‘fiscal drag’ or ‘output gap’ signal the theories you need to apply.
动笔之前，请先划出或高亮摘录中出现的每一个经济术语。“补贴”、“外部成本”、“引致需求”、“财政拖累”或“产出缺口”等词语，都在提示你需要应用的理论。
Then, group the concepts into micro and macro where relevant. For instance, a case study on sugary drinks might contain micro concepts (negative externality, price elasticity of demand, indirect tax) as well as macro links (effect on NHS spending, employment in the soft drinks industry).
然后，将概念按微观和宏观分类。比如，一篇关于含糖饮料的案例可能既包含微观概念（负外部性、需求价格弹性、间接税），也涉及宏观经济联系（对国民保健服务支出的影响、软饮料行业的就业）。
Create a quick spider diagram in the margin showing how these concepts connect to the data in the extract. This will keep your answer focused and prevent you from drifting into irrelevant theory.
在页边空白处快速画一张蜘蛛图，展示这些概念如何与摘录中的数据相关联。这会让你的回答始终紧扣主题，避免跑题到无关的理论上。
3. Applying Demand and Supply Analysis | 应用供需分析
Most Unit 1 case studies involve a change in a market. Begin by identifying the product and the factor(s) shifting demand (e.g. income, tastes, price of substitutes) or supply (e.g. costs of production, technology, taxes).
大多数第一单元的案例都涉及市场变化。首先要确定产品和导致需求变动（如收入、偏好、替代品价格）或供给变动（如生产成本、技术、税收）的因素。
Then, explain the adjustment process using precise terminology: an increase in demand shifts the demand curve to the right, causing a rise in equilibrium price and quantity, ceteris paribus. Always link the theory back to the specific market named in the case.
然后用精准的术语解释调整过程：需求增加使得需求曲线向右移动，导致均衡价格和均衡数量上升，其他条件不变。一定要将理论与案例中提到的具体市场联系起来。
If the extract contains numerical data or a graph, refer to the figures directly. For example: ‘The data shows that a £1.50 rise in the market price was accompanied by a 20% fall in quantity demanded, which suggests price elastic demand.’
如果摘录中包含数值数据或图表，请直接引用这些数字。例如：“数据显示，市场价格上涨1.50英镑，伴随需求量下降20%，这表明需求是富有价格弹性的。”
4. Interpreting Elasticity Data | 解读弹性数据
Case studies frequently include data that allows you to calculate or comment on price elasticity of demand (PED), income elasticity (YED) or cross-price elasticity (XED). The formula for PED is: %ΔQD ÷ %ΔP.
案例分析题常常会提供数据，让你计算或评论需求价格弹性（PED）、收入弹性（YED）或交叉价格弹性（XED）。PED 的公式为：需求量变动百分比 ÷ 价格变动百分比。
Interpreting the coefficient is crucial. A PED value of -0.5 indicates inelastic demand: quantity demanded is relatively unresponsive to price changes. This implies that a rise in price would increase total revenue. A PED of -1.6 suggests elastic demand, meaning a price rise would reduce total revenue.
解读弹性系数至关重要。PED 值为 -0.5 表明需求缺乏弹性：需求量对价格变动相对不敏感。这意味着提价会增加总收益。PED 值为 -1.6 则表明需求富有弹性，即提价会减少总收益。
Don’t just state the elasticity; explain its significance for producers, consumers or the government. For instance, if demand is inelastic, a government imposing an indirect tax will find that the tax is largely borne by consumers.
不要仅仅陈述弹性大小；要解释其对生产者、消费者或政府的意义。例如，如果需求缺乏弹性，政府征收间接税时会发现税负主要由消费者承担。
5. Identifying Market Failure | 识别市场失灵
Market failure occurs when the price mechanism leads to an inefficient allocation of resources. In a case study, look for evidence of negative externalities (pollution, passive smoking), positive externalities (vaccination, education), information failure, or public goods.
当价格机制导致资源配置无效率时，就出现了市场失灵。在案例中，要寻找负外部性（污染、被动吸烟）、正外部性（疫苗接种、教育）、信息不对称或公共物品的证据。
Draw a simple diagram in your answer: for a negative externality in consumption, show the marginal private benefit (MPB) curve above the marginal social benefit (MSB) curve, creating a welfare loss triangle.
在你的答案中画一张简图：对于消费的负外部性，画出边际私人收益（MPB）曲线位于边际社会收益（MSB）曲线上方，形成一个福利损失三角。
Always use the specific externality from the case. If the extract describes noise pollution from a new airport, explain how the market overproduces flights because airlines do not account for the external costs imposed on residents.
一定要使用案例中具体的外部性。如果摘录描述了新机场带来的噪音污染，请解释为何市场会产生过量的航班，因为航空公司没有考虑到强加给居民的外部成本。
6. Evaluating Government Policies | 评估政府政策
When the case study presents a policy solution — such as a tax, subsidy, regulation or tradable permit — you must evaluate its effectiveness. Start by explaining the intended mechanism: a tax internalises the externality, raising private cost towards social cost.
当案例呈现一项政策解决方案时——如税收、补贴、管制或可交易许可证——你必须评价其有效性。先从解释其预期机制开始：税收可以将外部性内部化，使私人成本向社会成本靠拢。
Then, assess the limitations. Indirect taxes may be regressive, placing a heavier burden on low-income households. They are less effective if demand is highly inelastic, as consumption falls only slightly. Regulations can be costly to enforce and may stifle innovation.
然后评估其局限性。间接税可能具有累退性，对低收入家庭造成更重的负担。如果需求高度缺乏弹性，税收的效果就会较差，因为消费量只会小幅下降。管制措施执行成本高，还可能抑制创新。
Where possible, compare alternative policies. A case study on obesity might mention a sugar tax, but you could argue that a combination of education and subsidies for healthy food might be more equitable and sustainable in the long run.
尽可能比较不同的政策选择。一个关于肥胖问题的案例可能会提到糖税，但你可以论证，教育与健康食品补贴相结合在长期可能更公平、更可持续。
7. Using Macroeconomic Indicators | 运用宏观经济指标
For Unit 2 case studies, you need to be comfortable interpreting data on economic growth (real GDP), CPI inflation, unemployment rates and the balance of payments on current account.
对于第二单元的案例，你需要熟练解读有关经济增长（实际 GDP）、CPI 通胀率、失业率以及经常账户收支的数据。
A common trap is to confuse a fall in the rate of inflation with deflation. If an extract states that inflation fell from 4% to 2%, the price level is still rising, just more slowly. Deflation would be a negative inflation rate, such as -1%.
一个常见的陷阱是把通胀率的下降与通货紧缩混为一谈。如果摘录指出通胀率从 4% 下降到了 2%，物价水平仍然在上升，只是升速放缓。通货紧缩是通胀率为负数，比如 -1%。
Link the indicators to the policy context. High unemployment and slow GDP growth might suggest the economy is in the recessionary phase of the trade cycle, justifying expansionary fiscal policy or lower interest rates.
将这些指标与政策背景联系起来。高失业率和缓慢的 GDP 增长可能意味着经济处于商业周期的衰退期，这为实施扩张性财政政策或降息提供了理由。
8. Constructing a Balanced Argument | 构建平衡的论点
Evaluation marks are awarded for weighing up different viewpoints and reaching a reasoned conclusion. A strong evaluative paragraph acknowledges the short-run versus long-run effects, the impact on different stakeholders, and the importance of the ‘ceteris paribus’ assumption.
评价分是给予权衡不同观点并得出有理有据的结论的能力。一个有力的评价段落应承认短期与长期影响的差异、对不同利益相关者的影响，以及“其他条件不变”假设的重要性。
Use phrases like ‘In the short run, the policy may lead to… However, in the long run, behavioural change could mean…’ or ‘While this benefits consumers through lower prices, it imposes costs on producers in the form of reduced profits.’
可以使用这样的表述：“短期内，该政策可能会导致……然而，长期来看，行为改变可能意味着……”或者“虽然这通过降低价格使消费者受益，但它以利润减少的形式给生产者带来了成本”。
Always support your evaluation with evidence from the case. A speculative point without grounding in the data will not earn high marks.
一定要用案例中的证据来支持你的评价。没有数据支撑的猜测性观点不会得到高分。
9. Time Management and Exam Technique | 时间管理与考试技巧
In the WJEC AS paper, case study questions are often allocated a specific number of marks, and you should spend roughly one minute per mark. For a 10-mark analysis question, plan for two to three minutes of planning and seven to eight minutes of writing.
在 WJEC AS 试卷中，案例分析题通常有明确的分数分配，你大约可以按每分钟一分的节奏来答题。对于一道 10 分的分析题，规划两到三分钟的构思和七到八分钟的书写时间。
Read the questions before the extract. This allows you to read the case with purpose, spotting the data you need immediately. Underline figures and trends as you go.
在阅读摘录之前先读题目。这样你就能有目的地阅读案例，立即发现你所需的数据。同时随手划出数字和变化趋势。
Leave the 14-mark or 15-mark evaluation question for last, but ensure you have enough time to write at least two developed evaluative points with a conclusion.
将 14 分或 15 分的评价题留到最后作答，但要确保有足够的时间写出至少两个展开的评价点和一个结论。
10. Common Pitfalls and How to Avoid Them | 常见误区及如何避免
One major pitfall is repeating the extract without adding economic analysis. The examiner knows what the case says; your job is to explain why it is happening using economic models.
一个主要误区是复述摘录内容而没有加入经济分析。阅卷官知道案例说了什么；你的任务是用经济模型解释为什么会发生这种现象。
Another mistake is listing points without developing them. Instead of mentioning three policies in a single sentence, choose one and develop it fully: explain the mechanism, draw the diagram, and then evaluate.
另一个错误是罗列要点而不展开。与其用一句话提及三项政策，不如选择一项并将其充分展开：解释机制、画出图示，然后进行评价。
Avoid using vague terms like ‘the economy will improve’. Specify by what measure (real GDP, employment, price stability) and over what time horizon.
避免使用“经济将会改善”这样模糊的表述。要明确指出用何种指标衡量（实际 GDP、就业、物价稳定）以及在多长时间范围内。
11. Worked Example: The Housing Market | 案例详解：住房市场
Case extract: ‘The UK housing market has seen price rises of 8% per annum, fuelled by low interest rates and a shortage of new builds. First-time buyers are struggling, and the government is considering a new tax on vacant properties.’
案例摘录：“受低利率和新建住房短缺推动，英国住房市场价格年均上涨 8%。首次购房者举步维艰，政府正考虑对空置房产征收新税。”
Analysis: The primary microeconomic cause is a rightward shift in demand (low mortgage rates increase affordability) coupled with an inelastic supply curve in the short run (building houses takes time). Draw a diagram showing demand shifting right along a steep supply curve, causing a large price rise and only a modest quantity increase.
分析：主要的微观经济原因是需求曲线向右移动（低按揭利率提高了购房能力），加上短期内供给曲线缺乏弹性（建房需要时间）。画一张图，显示需求曲线沿陡峭的供给曲线向右移动，导致价格大幅上升而数量仅小幅增加。
Evaluation of the vacant property tax: A tax on empty homes aims to shift the supply of housing to the right by encouraging owners to rent or sell. However, the effectiveness depends on the price elasticity of supply. If planning restrictions remain tight, supply may still be inelastic, limiting the impact. The tax also raises equity concerns: it might unfairly penalise people who inherit property but cannot afford to renovate it.
对空置房产税的评价：对空置房屋征税旨在通过鼓励业主出租或出售，使住房供给曲线向右移动。然而，其有效性取决于供给价格弹性。如果规划限制依然严格，供给可能仍缺乏弹性，从而限制税收的影响。该税也引发了公平方面的担忧：它可能会不公平地惩罚那些继承了房产却无力翻新的人。
12. Practice Case Study: Sugar Tax | 实战案例：糖税
Case extract: ‘In 2023, Country X introduced a £0.24 per litre levy on sugary drinks. In the first year, consumption fell by 12%, while government revenue reached £350 million. However, employment in the soft drinks sector declined by 2%. Public health groups argue the tax should be doubled, but industry bodies warn of job losses and higher prices for low-income families.’
案例摘录：“2023 年，X 国对含糖饮料征收每升 0.24 英镑的税。第一年，消费量下降了 12%，而政府收入达到 3.5 亿英镑。然而，软饮料行业的就业下降了 2%。公共卫生组织主张税率翻倍，但行业机构警告这将导致失业和低收入家庭面临更高价格。”
Task: Using the extract, explain why sugary drinks are a case of market failure and evaluate the sugar tax as a policy remedy.
任务：利用摘录内容，解释为何含糖饮料是市场失灵的一个例子，并评价糖税作为一项政策补救措施的效果。
Market failure explanation: Overconsumption of sugary drinks generates negative externalities in the form of obesity-related illnesses, which increase healthcare costs for society. The free market equilibrium (Qm) is greater than the social optimum (Qs), as consumers only consider private benefit. This is a classic negative externality in consumption.
市场失灵的解释：含糖饮料的过度消费会以肥胖相关疾病的形式产生负外部性，增加社会的医疗成本。自由市场均衡数量（Qm）大于社会最优数量（Qs），因为消费者只考虑私人收益。这是典型的消费负外部性。
Tax evaluation: The levy internalises the externality, raising the price from P1 to P2 and reducing quantity demanded. The 12% fall in consumption suggests demand is relatively price elastic in the long run, as consumers switch to diet drinks or water. Revenue of £350 million could hypothetically fund public health programmes. However, the tax is regressive, absorbing a larger proportion of income from poorer households. The 2% fall in sector employment indicates a trade-off between health gains and economic livelihoods. Doubling the tax might cause diminishing returns, as the remaining consumers are likely more price inelastic, and it could fuel a black market for untaxed imports.
税收评价：该税将外部性内部化，将价格从 P1 提高到 P2，并减少了需求量。消费量下降 12% 表明，长期来看需求相对富有价格弹性，因为消费者转向了无糖饮料或水。3.5 亿英镑的收入假设可以用于资助公共卫生项目。然而，该税具有累退性，占低收入家庭收入的比例更大。行业就业下降 2% 表明健康收益与经济生计之间存在权衡。将税率翻倍可能会导致收益递减，因为剩下的消费者很可能更缺乏价格弹性，而且还可能催生未税进口品的黑市。
Published by TutorHao | Economics Revision Series | aleveler.com
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