📚 SQA Economics Case Study Practice: The Coffee Market | SQA 经济案例分析实战：咖啡市场
Case studies are a powerful way to test your understanding of economic theory. In this practice exercise, we explore the global coffee market, applying key concepts from SQA National 5 Economics. You will analyse demand and supply factors, equilibrium shifts, elasticity, government intervention, and market failure. Work through each section like a detective, using the data and economic reasoning to build your answers.
案例分析是检验你经济学理论理解的有效方式。在这个实战练习中，我们将探讨全球咖啡市场，运用SQA National 5 经济学中的关键概念。你将分析需求与供给因素、均衡变动、弹性、政府干预以及市场失灵。像侦探一样逐步完成每一节，利用数据和经济推理构建你的答案。
1. Case Background | 案例背景
The global coffee bean market is worth over £70 billion annually. Brazil and Vietnam account for nearly half of world production. In 2024, a severe drought in Brazil reduced harvests by 15%. At the same time, demand for specialty coffee drinks surged among younger consumers. The UK government is considering a 'caffeine health levy' of £0.20 per cup on coffee and energy drinks, aiming to reduce consumption and raise revenue. This case asks you to explain the economic consequences of these changes.
全球咖啡豆市场年产值超过700亿英镑。巴西和越南的产量几乎占世界总产量的一半。2024年，巴西的严重干旱使咖啡收成减少了15%。与此同时，年轻消费者对特色咖啡饮品的需求激增。英国政府正考虑对咖啡和能量饮料征收每杯0.20英镑的「咖啡因健康税」，旨在减少消费并增加税收。本案例要求你解释这些变化的经济后果。
Key agents in the market include coffee farmers, roasting companies, cafes, and consumers. You should consider their incentives and how they respond to price signals.
市场中的关键主体包括咖啡农、烘焙企业、咖啡馆和消费者。你应考虑他们的激励因素以及他们如何对价格信号做出反应。
2. Demand Analysis | 需求分析
Demand for coffee has been rising for several reasons. Firstly, a change in tastes and preferences: social media trends have made artisan coffees like flat whites and cold brews status symbols among 16-30 year-olds. This is a non-price determinant that shifts the demand curve to the right. Secondly, income growth in emerging economies has increased the number of consumers who can afford daily coffee purchases. Thirdly, the price of complementary goods, such as oat milk and coffee syrups, has fallen, making coffee consumption more attractive.
咖啡需求因多个原因一直在上升。首先，口味和偏好的变化：社交媒体趋势使馥芮白、冷萃等精品咖啡成为16-30岁人群的身份象征。这是一个非价格决定因素，使需求曲线向右移动。其次，新兴经济体的收入增长增加了能够承担每日咖啡支出的消费者数量。第三，互补品的价格，如燕麦奶和咖啡糖浆，已经下降，使咖啡消费更具吸引力。
Using a demand schedule, suppose at a price of £3.00 per cup, quantity demanded is 500,000 cups per day in the UK. If tastes change, at the same price, demand might rise to 620,000 cups. This illustrates an increase in demand, not merely movement along the curve.
使用需求表，假设每杯价格为3.00英镑，英国每天的需求量为50万杯。如果口味改变，在相同价格下，需求可能升至62万杯。这说明了需求的增加，而不仅仅是沿着曲线的移动。
3. Supply Analysis | 供给分析
On the supply side, the drought in Brazil is a negative supply shock. Weather conditions affect the costs of production and the quantity producers can bring to market. Reduced rainfall destroyed crops and raised the cost per bag of beans. This shifts the supply curve to the left. Other supply-side factors include rising fertiliser prices and shipping disruptions, which increase the cost of getting coffee from farms to roasters.
在供给方面，巴西的干旱是一个负面的供给冲击。天气状况影响生产成本以及生产者能推向市场的数量。降雨减少摧毁了作物，抬高了每袋咖啡豆的成本。这使供给曲线向左移动。其他供给侧因素包括化肥价格上涨和航运中断，这些增加了将咖啡从农场运到烘焙商的成本。
Consider a typical supply schedule: at a price of £3.00, farmers are willing to supply 480,000 cups' worth of beans. After the drought, at the same price, they may only supply 370,000 cups. This decrease in supply is shown by a leftward shift.
考虑一个典型的供给表：在3.00英镑的价格下，农民愿意供应相当于48万杯咖啡的咖啡豆。干旱之后，在相同价格下，他们可能只供应37万杯。这种供给的减少表现为向左移动。
4. Market Equilibrium | 市场均衡
Equilibrium occurs where quantity demanded equals quantity supplied. Initially, the market cleared at price £3.00 and quantity 500,000 cups. With the demand increase and supply decrease, both curves shift. A rightward demand shift puts upward pressure on price, as does a leftward supply shift. The new equilibrium price will definitely be higher, though the change in equilibrium quantity is ambiguous without knowing the magnitude of shifts. Suppose the new equilibrium price rises to £3.80 and quantity settles at 450,000 cups per day.
当需求量等于供给量时，达到均衡。最初，市场在价格3.00英镑和数量50万杯处出清。随着需求增加和供给减少，两条曲线都发生移动。需求向右移动对价格产生上行压力，供给向左移动也是如此。新的均衡价格肯定会更高，但均衡数量的变化在没有了解移动幅度时是不确定的。假设新的均衡价格升至3.80英镑，数量稳定在每天45万杯。
This outcome shows that consumers face higher prices and, in this scenario, total consumption falls. Producers receive a higher price per unit but sell fewer units. The net effect on revenue depends on the price elasticity of demand.
这一结果表明消费者面临更高的价格，而且在这种情景下，总消费量下降。生产者每单位得到更高的价格，但售出的单位数减少。对收入的净效应取决于需求价格弹性。
5. Price Elasticity of Demand | 需求价格弹性
Price elasticity of demand (PED) measures the responsiveness of quantity demanded to a change in price. We calculate PED using the formula:
需求价格弹性（PED）衡量需求量对价格变化的反应程度。我们使用以下公式计算PED：
PED = %ΔQd / %ΔP
From our earlier data, price increased from £3.00 to £3.80, a 26.7% rise. Quantity demanded fell from 500,000 to 450,000, a 10% fall. Therefore:
根据我们之前的数据，价格从3.00英镑涨至3.80英镑，涨幅26.7%。需求量从50万降至45万，下降10%。因此：
PED = -10% / 26.7% ≈ -0.37 (ignoring sign, 0.37)
Since PED < 1, demand for coffee in this market is price inelastic. This means consumers are not very responsive to price changes. The main reason is that coffee is habit-forming and has few close substitutes for regular drinkers. For a firm, this implies raising price will increase total revenue, because the percentage fall in quantity is less than the percentage rise in price.
由于PED < 1，该市场咖啡的需求是缺乏弹性的。这意味着消费者对价格变化不太敏感。主要原因是咖啡有成瘾性，且对常饮者来说几乎没有近似替代品。对企业而言，这意味着提高价格将增加总收入，因为数量下降的百分比小于价格上升的百分比。
6. Price Elasticity of Supply | 供给价格弹性
Price elasticity of supply (PES) measures how responsive quantity supplied is to a change in price. Coffee supply tends to be inelastic in the short run because it takes years for new coffee plants to mature. After the drought, the PES is particularly low. Suppose the price rose by 26.7% but quantity supplied only increased by 3% as farmers clear damaged trees. Then:
供给价格弹性（PES）衡量供给量对价格变化的反应程度。咖啡供给在短期内往往缺乏弹性，因为新咖啡树需要数年才能成熟。干旱之后，PES 尤其低。假设价格上涨了26.7%，但供给量仅因农民清理受损树木而增加了3%。那么：
PES = %ΔQs / %ΔP = 3% / 26.7% ≈ 0.11
PES < 1 indicates inelastic supply. Farmers cannot quickly expand output. This inelasticity exacerbates price spikes when demand rises or supply falls. Over a longer time horizon, as new plantations are established, supply becomes more elastic.
PES < 1 表明供给缺乏弹性。农民无法迅速扩大产出。这种缺乏弹性加剧了需求上升或供给下降时的价格暴涨。在较长的时间范围内，随着新种植园的建立，供给会变得更有弹性。
7. Government Intervention: Taxation | 政府干预：征税
The proposed caffeine health levy is an indirect tax. A tax of £0.20 per cup is a specific tax, shifting the supply curve vertically upward by the amount of the tax. Producers now need to receive the original price plus £0.20 to supply each unit. This is shown as a leftward shift of the supply curve. The new equilibrium price for consumers rises, while the price received by producers falls by less than the full tax amount, depending on elasticities.
拟议的咖啡因健康税是一种间接税。每杯0.20英镑的税属于从量税，使供给曲线垂直向上移动税额的幅度。现在生产者需要获得原价再加0.20英镑才愿意供应每单位。这表现为供给曲线向左移动。消费者支付的新均衡价格上升，而生产者收到的价格下降幅度小于全额税额，具体取决于弹性。
ply we identified, the consumer tax burden will be larger. Suppose pre-tax equilibrium was £3.80 for 450,000 cups. After the £0.20 tax, the consumer price might rise to £3.95, and the producer receives £3.75. The tax revenue collected is £0.20 × the new quantity, which might fall to 430,000 cups.
根据我们确定的缺乏弹性的需求和缺乏弹性的供给，消费者的税收负担会更大。假设税前均衡为3.80英镑，45万杯。征收0.20英镑的税后，消费者价格可能升至3.95英镑，生产者得到3.75英镑。征收的税收收入为0.20英镑 × 新的数量，新数量可能降至43万杯。
8. Tax Incidence and Welfare | 税收归宿与福利
Tax incidence refers to how the burden of a tax is divided between consumers and producers. With inelastic demand and supply, both parties bear a share, but the more inelastic side bears the greater burden. Here, demand (PED 0.37) is more inelastic than supply (PES 0.11)? Actually, PES is 0.11, which is more inelastic than PED 0.37. Therefore, producers bear the larger share of the tax burden. This is because they have little ability to adjust output in the short run. Their received price falls significantly, while consumers see only a modest price increase.
税收归宿是指税负如何在消费者和生产者之间分担。在需求和供给都缺乏弹性的情况下，双方各承担一部分，但更缺乏弹性的一方承担更大的负担。在此例中，供给弹性（PES 0.11）比需求弹性（PED 0.37）更缺乏弹性。因此，生产者承担的税负份额更大。这是因为他们在短期内调整产出的能力很弱。他们收到的价格大幅下降，而消费者只看到温和的价格上涨。
Welfare analysis shows a deadweight loss (DWL). The tax reduces quantity traded from 450,000 to 430,000 cups. The lost consumer and producer surplus that is not transferred to government revenue is the DWL. Because both curves are inelastic, the DWL is relatively small, but it still represents a loss of economic efficiency.
福利分析显示存在无谓损失（DWL）。税收使交易量从45万杯减少到43万杯。损失的消费者和生产者剩余中，没有转化为政府税收的部分即为无谓损失。由于两条曲线都缺乏弹性，无谓损失相对较小，但它仍然代表着经济效率的损失。
9. Market Failure: Negative Externalities | 市场失灵：负外部性
The government justifies the tax by pointing to negative externalities associated with caffeine consumption. These include long-term health problems such as anxiety and sleep disorders, which increase NHS costs. Additionally, productivity losses from caffeine-induced insomnia affect the wider economy. In a free market, consumers only consider their private costs (the price of coffee) and private benefits, ignoring these external costs. This leads to overconsumption of coffee compared to the socially optimal level.
政府以咖啡因消费相关的负外部性为该税进行辩护。这些外部性包括焦虑、睡眠障碍等长期健康问题，这会增加国民保健服务（NHS）的成本。此外，由咖啡因导致的失眠所引起的生产力损失会影响更广泛的经济。在自由市场中，消费者只考虑他们的私人成本（咖啡价格）和私人利益，而忽视了这些外部成本。这导致咖啡的消费量超过了社会最优水平。
The tax aims to internalise the externality. By adding £0.20 per cup, the private cost rises closer to the social cost, reducing quantity consumed towards the socially efficient level. However, the tax is a blunt instrument; it does not distinguish between moderate and excessive consumers. It may also be regressive, taking a larger share of income from low-income households.
该税旨在使外部性内部化。通过每杯增加0.20英镑，私人成本更接近社会成本，使消费量降至社会有效率的水平。然而，税收是一种粗糙的工具；它不区分适量和过度消费者。它还可能是累退的，从低收入家庭拿走更大比例的收入。
10. Evaluation and Conclusion | 评估与结论
In evaluating the government's proposed tax, we must weigh its effectiveness against unintended consequences. The tax is likely to reduce coffee consumption only modestly due to inelastic demand. It will raise significant revenue, which could hypothecate towards health services. However, coffee shops may experience reduced profits, possibly leading to job losses. There is also a risk of illicit trade or home-brewing to avoid the tax. Moreover, the tax might not address the root causes of overconsumption, such as workplace culture and lack of sleep education.
在评估政府的税收提议时，我们必须权衡其效果与意外后果。由于需求缺乏弹性，该税可能仅会小幅减少咖啡消费。它将筹集可观的收入，这些收入可被专项用于卫生服务。然而，咖啡店的利润可能减少，可能导致失业。还存在为避税而进行非法交易或家庭自制的风险。此外，税收可能无法解决过度消费的根本原因，比如职场文化和睡眠教育的缺失。
A full evaluation would consider alternative policies: a public awareness campaign about caffeine risks, subsidies for decaf options, or regulations on advertising. The case demonstrates how a combination of supply shocks, demand shifts, and government policy shape market outcomes. When approaching your SQA exam, remember to define your terms, use diagrams (even if only described in words), apply data, and always offer a balanced evaluation.
完整的评估还应考虑替代政策：关于咖啡因风险的公众宣传活动、对脱因咖啡的补贴，或对广告的监管。本案例展示了供给冲击、需求变动和政府政策如何共同塑造市场结果。在应对SQA考试时，请记住定义术语、使用图表（即使仅用文字描述）、应用数据，并始终给出平衡的评估。
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