Year 13 OCR Economics: Case Study Practice in Action | 案例分析实战演练

📚 Year 13 OCR Economics: Case Study Practice in Action | 案例分析实战演练

Case studies are a crucial component of OCR A-Level Economics, testing your ability to apply economic theories to real-world contexts. This article offers a step-by-step walkthrough using a global coffee market scenario, covering microeconomic, macroeconomic and global economy topics. You will learn how to analyse data, evaluate policies and structure high-scoring answers.

案例分析是OCR A-Level经济学的核心组成部分，考查你将经济理论应用于实际情境的能力。本文将通过全球咖啡市场情景，进行分步演练，涵盖微观经济、宏观经济和全球经济主题。你将学会如何分析数据、评估政策并构建高分答案。

1. Understanding the Case: The Global Coffee Market | 理解案例：全球咖啡市场

The coffee industry is an excellent case study because it links production in developing countries with consumption in advanced economies. Coffee is a perennial crop with a lag of several years between planting and first harvest, making supply highly price-inelastic in the short run. Price volatility is driven by weather shocks, pests and speculative trading on commodity exchanges.

咖啡行业是一个绝佳的案例，因为它将发展中国家的生产与发达经济体的消费联系起来。咖啡是多年生作物，从种植到首次收获有数年滞后，使得短期供给高度缺乏价格弹性。价格波动由天气冲击、病虫害以及商品交易所的投机交易驱动。

Key players include Brazil and Vietnam (major exporters), multinational roasting corporations like Nestlé and Starbucks, and over 25 million smallholders. A memorable example was the 1997–2002 coffee crisis when real prices fell to historic lows, illustrating producer vulnerability and the need for intervention.

主要参与者包括巴西和越南（主要出口国）、雀巢和星巴克等跨国烘焙公司，以及超过2500万小农户。一个令人印象深刻的例子是1997–2002年的咖啡危机，当时实际价格跌至历史低点，凸显了生产者的脆弱性和干预的必要性。

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2. Microeconomic Analysis: Supply and Demand Shocks | 微观分析：供需冲击

On the supply side, a frost in Brazil destroys part of the crop, shifting the supply curve leftwards from S1 to S2. Because coffee trees take years to mature, the short-run price elasticity of supply (PES) is very low, often estimated around 0.2. This means that a given price increase generates only a small quantity response, leading to sharp price spikes.

在供给方面，巴西的一场霜冻摧毁部分收成，使供给曲线从S1向左移动到S2。由于咖啡树需要数年才能成熟，短期供给价格弹性（PES）非常低，通常估计在0.2左右。这意味着给定的价格上涨只能引发很小的产量反应，从而导致价格急剧飙升。

On the demand side, coffee consumption in developed countries is relatively income-inelastic, but it is more elastic in emerging markets. Speculative activity in futures markets can create demand-side shocks unrelated to physical consumption, shifting the demand curve and amplifying volatility. Students should be able to show these shifts on a supply–demand diagram and calculate PED values where data are provided.

在需求方面，发达国家的咖啡消费相对缺乏收入弹性，而新兴市场的弹性更大。期货市场的投机活动会制造与实际消费无关的需求侧冲击，移动需求曲线并放大波动。学生应能在供需图上展示这些移动，并在提供数据时计算出需求的价格弹性值。

PES = (%Δ Quantity Supplied) ÷ (%Δ Price) < 1

PES = (供给量变化百分比) ÷ (价格变化百分比) < 1

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3. Market Structure and Power | 市场结构与市场力量

The roasting and retail stages of the coffee value chain are characterised by an oligopsony: a few large firms dominate the purchasing of coffee beans. This gives them significant bargaining power over fragmented smallholder farmers. We can apply monopsony theory to understand how farmers receive a price below the value of their marginal product (VMP).

咖啡价值链的烘焙和零售阶段具有寡头买方垄断特征：少数大企业主导咖啡豆的采购。这使它们对分散的小农户具有强大的议价能力。我们可以运用买方垄断理论来理解农民如何获得低于其边际产品价值（VMP）的价格。

In a monopsonistic input market, the firm maximises profit by equating marginal factor cost (MFC) to marginal revenue product (MRP). Since MFC lies above the average factor cost (AFC), the equilibrium price paid is lower than in a perfectly competitive market, leading to exploitation. A diagram showing MFC, AFC and MRP is essential for high analysis marks.

在买方垄断的要素市场中，企业通过使边际要素成本（MFC）等于边际收益产品（MRP）来实现利润最大化。由于MFC位于平均要素成本（AFC）之上，均衡支付的价格低于完全竞争市场，从而导致剥削。展示MFC、AFC和MRP的图表对于获得高分析分至关重要。

Price paid to farmers < VMP of labour/coffee

支付给农民的价格 < 劳动/咖啡的边际产品价值

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4. Market Failure and Externalities | 市场失灵与外部性

Coffee production generates significant negative externalities. Expanding sun-grown coffee plantations leads to deforestation, biodiversity loss and increased carbon emissions. These social costs are not reflected in the market price, resulting in over-production relative to the socially optimal level.

咖啡生产会产生显著的负外部性。扩大阳光种植咖啡园导致森林砍伐、生物多样性丧失和碳排放增加。这些社会成本并未反映在市场价格中，导致产量超过社会最优水平。

Positive externalities also exist. Shade-grown coffee preserves forest habitats, sequesters carbon and protects watersheds. Information failure is widespread: consumers often lack knowledge about sustainable certifications such as Fairtrade or Organic, leading to under-consumption of environmentally friendly coffee. This creates scope for government intervention through labelling, subsidies or taxes.

正外部性同样存在。荫蔽种植的咖啡能保护森林栖息地、固碳并保护流域。信息失灵普遍存在：消费者通常不了解公平贸易或有机等可持续认证，导致对环境友好的咖啡消费不足。这为政府通过标识、补贴或税收进行干预提供了空间。

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5. Macroeconomic Impacts | 宏观经济影响

For coffee-dependent economies like Ethiopia or Honduras, coffee exports can account for over 30% of total export earnings. When world prices fall, export revenues decline, worsening the current account balance on the balance of payments. This can trigger a depreciation of the domestic currency, raising the cost of imports and imported inflation.

对于埃塞俄比亚或洪都拉斯等依赖咖啡的经济体，咖啡出口可占其总出口收入的30%以上。当世界价格下跌时，出口收入减少，国际收支中的经常账户恶化。这可能会引发本币贬值，提高进口成本和输入性通胀。

Falling export income reduces aggregate demand (AD) via lower net exports (X–M), potentially opening a negative output gap and increasing cyclical unemployment. Through the multiplier effect, the initial fall in export revenue can contract national income by a larger amount. The government’s tax base shrinks, limiting expenditure on public goods and human capital, which harms long-run economic growth on the LRAS side.

出口收入下降通过净出口（X–M）减少降低总需求（AD），可能开启负产出缺口并增加周期性失业。通过乘数效应，出口收入的最初下降会以更大的幅度收缩国民收入。政府税基缩水，限制了公共品和人力资本支出，从而在长期总供给（LRAS）一侧损害长期经济增长。

ΔGDP = k × ΔExports, where k = 1/(MPS + MPT + MPM)

ΔGDP = k × Δ出口，其中 k = 1/(边际储蓄倾向 + 边际税收倾向 + 边际进口倾向)

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6. International Trade and Comparative Advantage | 国际贸易与比较优势

Brazil and Vietnam have a comparative advantage in coffee production due to favourable climatic conditions and an abundance of low-cost labour. According to the Heckscher–Ohlin model, these nations specialise in and export the good that uses their abundant factor intensively. However, over-specialisation makes them vulnerable to the Prebisch–Singer hypothesis, which suggests a long-term decline in the terms of trade for primary commodity exporters relative to manufactured goods.

巴西和越南因有利的气候条件和充裕的低成本劳动力而在咖啡生产上具有比较优势。根据赫克歇尔–俄林模型，这些国家专业化生产并出口密集使用其丰裕要素的商品。然而，过度专业化使它们容易受到普雷维什–辛格假说的影响，该假说认为初级产品出口国的贸易条件相对于制成品呈长期下降趋势。

Trade barriers such as tariff escalation further disadvantage developing countries. Import tariffs on processed coffee (e.g. roasted) are typically much higher than on green beans, discouraging value-added processing in producing nations. This limits industrial diversification and perpetuates dependence on volatile commodity prices.

关税升级等贸易壁垒进一步使发展中国家处于不利地位。对加工咖啡（如烘焙）的进口关税通常远高于生豆，阻碍了生产国的增值加工。这限制了产业多样化，并延续了对波动性商品价格的依赖。

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7. Development Economics Perspective | 发展经济学视角

The coffee sector illustrates the dual economy model: a traditional, low-productivity agricultural sector coexists with a modern, globally integrated market. Many smallholders are caught in a poverty trap, where low incomes prevent investment in fertilisers, seedlings or

Published by TutorHao | Year 13 Economics Revision Series | aleveler.com

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