📚 Year 12 OCR Economics: Key Terminology Quick Revision Guide | Year 12 OCR 经济学：核心术语速记指南
Mastering essential economic terminology is crucial for success in Year 12 OCR Economics. This guide provides concise definitions and explanations of key terms across both microeconomics and macroeconomics, helping you build a solid foundation for exam answers and essays. Every definition is paired with the analytical language that examiners reward, so you can move from stating a term to using it inside a chain of reasoning. Use this as a quick reference to reinforce your understanding and recall.
掌握基本经济学术语对 Year 12 OCR 经济学的成功至关重要。本指南提供微观经济学和宏观经济学核心术语的简明定义与解释，帮助您为考试答案和论文打下坚实基础。每条定义都配有考官真正给分的分析性语言，让你从单纯背出术语，进阶到把术语嵌入推理链条之中。可将其用作快速参考，以巩固理解和记忆。
1. The Economic Problem: Scarcity, Choice and Opportunity Cost | 经济问题：稀缺性、选择与机会成本
Scarcity refers to the fundamental condition where finite resources are insufficient to satisfy all human wants. Because of scarcity, individuals, firms and governments must make choices about how to allocate resources efficiently. Wants are unlimited and recurring, while resources are limited in supply, so every economy must decide what to produce, how to produce it, and for whom to produce it.
稀缺性是指有限资源无法满足所有人类欲望的基本状况。由于稀缺，个人、企业和政府必须就如何有效配置资源做出选择。欲望是无限且不断再生的，而资源供给有限，因此每个经济体都必须决定生产什么、如何生产以及为谁生产。
Opportunity cost is the value of the next best alternative that is sacrificed when a choice is made. It represents the true cost of any decision in terms of foregone benefits. Crucially, opportunity cost is not simply the money spent; it is what is given up, which may include time, leisure, consumer goods, or the next best use of a factor of production.
机会成本是做出选择时所放弃的下一个最佳替代品的价值。它代表任何决策的真实成本，即所放弃的收益。关键在于，机会成本不只是花掉的钱，而是被放弃的东西，可能包括时间、闲暇、消费品，或某一生产要素的次优用途。
Opportunity cost of one extra unit of X = units of Y given up ÷ extra units of X produced
Free goods, such as air or sunlight, have zero opportunity cost because they are unlimited in supply. Economic goods have an opportunity cost because scarce resources were used to produce them. Rational decision makers also use marginal analysis: they continue an activity as long as marginal benefit is greater than or equal to marginal cost.
自由品（如空气、阳光）因供给无限，机会成本为零。经济品则有机会成本，因为生产它们使用了稀缺资源。理性决策者还使用边际分析：只要边际收益大于或等于边际成本，就继续该活动。
2. Factors of Production and Factor Incomes | 生产要素与要素收入
The factors of production are the inputs used to produce goods and services. They are commonly classified as land, labour, capital and enterprise, and each factor earns a distinct reward, known as factor income.
生产要素是用于生产商品和服务的投入。通常分为土地、劳动、资本和企业家才能，每种要素获得不同的报酬，即要素收入。
| Factor | 要素 | Reward | 报酬 | Example | 例子 |
| Land 土地 | Rent 租金 | Farmland, oil reserves 农田、石油储量 |
| Labour 劳动 | Wages 工资 | Workers, managers 工人、管理者 |
| Capital 资本 | Interest 利息 | Machines, factories 机器、厂房 |
| Enterprise 企业家才能 | Profit 利润 | Entrepreneur who takes risk 承担风险的企业家 |
Do not confuse capital with money. In economics, capital means capital goods, also called physical capital, that are used to produce other goods. Financial capital such as shares or bank deposits is not itself a factor of production. Human capital refers to the skills and knowledge embodied in workers, improved by education and training.
不要把资本与货币混淆。在经济学中，资本指资本品（也称物质资本），用于生产其他商品。股票、银行存款等金融资本本身不是生产要素。人力资本指凝结在劳动者身上的技能与知识，通过教育和培训提升。
Factor mobility describes how easily factors move between uses. Occupational mobility is the ease of moving between jobs; geographical mobility is the ease of moving between locations. Factor endowment describes the quantity and quality of factors a country possesses, which influences its comparative advantage. Specialisation and the division of labour raise output per worker but can cause worker alienation and vulnerability to supply shocks.
要素流动性描述要素在不同用途间转移的难易程度。职业流动性指在不同工作之间转换的难易；地域流动性指在不同地区之间迁移的难易。要素禀赋指一国拥有的要素数量与质量，决定其比较优势。专业化与劳动分工提高人均产出，但也可能造成工人异化和对供给冲击的脆弱性。
3. Production Possibility Frontiers | 生产可能性边界
A production possibility frontier shows the maximum combinations of two goods that an economy can produce when all its resources are fully and efficiently employed, given a fixed level of technology. It is a model of opportunity cost, choice and trade-off.
生产可能性边界表示在资源被充分且有效利用、技术水平既定的条件下，一个经济体所能生产的两种商品的最大组合。它是机会成本、选择和权衡取舍的模型。
- On the curve: productive efficiency is achieved. 位于曲线上：实现了生产效率。
- Inside the curve: unemployed or inefficiently used resources. 位于曲线内：存在失业或资源使用无效率。
- Outside the curve: unattainable with current resources. 位于曲线外：以现有资源无法达到。
- Outward shift: economic growth or an increase in the quantity or quality of factors. 曲线外移：经济增长或要素数量、质量的提升。
A concave, bowed-out frontier illustrates increasing opportunity cost, because resources are not perfectly substitutable between the two goods. A straight-line frontier would imply constant opportunity cost. Note the distinction between actual growth, which is a movement towards the frontier, and potential growth, which is an outward shift of the frontier itself.
向外凸（凹向原点）的边界说明机会成本递增，因为资源在两种商品之间并非可以完全替代。直线型边界则意味着机会成本不变。要注意区分实际增长（向边界移动）与潜在增长（边界本身向外移动）。
The classic capital goods versus consumer goods diagram is a favourite exam question: an economy that produces more capital goods today sacrifices current consumption but shifts its frontier out faster in the future.
经典的资本品与消费品图形是考试高频题：今天多生产资本品会牺牲当前消费，但未来边界外移得更快。
4. Demand, Supply and Market Equilibrium | 需求、供给与市场均衡
Demand is the quantity of a good that consumers are willing and able to buy at a given price over a period of time. The law of demand states that, ceteris paribus, as price falls, quantity demanded rises, explained by the income effect, the substitution effect and diminishing marginal utility.
需求是消费者在某一价格下、在一定时期内愿意且有能力购买的某商品数量。需求定律指出，在其他条件不变时，价格下降则需求量上升，可用收入效应、替代效应和边际效用递减来解释。
Supply is the quantity producers are willing and able to offer for sale at a given price. The law of supply states that, ceteris paribus, a higher price leads to a higher quantity supplied, because higher prices raise profitability and cover rising marginal costs.
供给是生产者在某一价格下愿意且有能力出售的数量。供给定律指出，在其他条件不变时，价格越高，供给量越大，因为更高价格提高盈利性并覆盖上升的边际成本。
Examiners constantly test the difference between a movement along a curve and a shift of a curve. A change in the good's own price causes a movement along the curve, described as an extension or contraction of demand. A change in any other determinant causes a shift, described as an increase or decrease in demand.
考官反复考查曲线上的移动与整条曲线的移动之间的区别。商品自身价格变化导致沿曲线的移动，称为需求的扩张或收缩。任何其他决定因素的变化导致整条曲线移动，称为需求的增加或减少。
- Conditions of demand: population, advertising, substitutes and complements, income, fashion and taste, interest rates, expectations. 需求条件：人口、广告、替代品与互补品、收入、时尚与偏好、利率、预期。
- Conditions of supply: productivity, indirect taxes and subsidies, number of firms, technology, weather, costs of production, government regulation. 供给条件：生产率、间接税与补贴、企业数量、技术、天气、生产成本、政府管制。
Equilibrium price is where planned demand equals planned supply, so there is no tendency for price to change. Above equilibrium there is a surplus, or excess supply, which pushes price down; below equilibrium there is a shortage, or excess demand, which pushes price up. The price mechanism performs three functions: rationing, signalling and providing incentives.
均衡价格是计划需求等于计划供给的价格，此时价格没有变动趋势。高于均衡价格出现过剩（超额供给），推动价格下降；低于均衡价格出现短缺（超额需求），推动价格上升。价格机制发挥三项功能：配给、信号和激励。
5. Elasticity of Demand and Supply | 需求弹性与供给弹性
Elasticity measures the responsiveness of one variable to a change in another. It is a units-free measure, which is why it is so useful for comparing different markets.
弹性衡量一个变量对另一个变量变化的反应程度。它是无单位的度量，因此非常适合比较不同市场。
PED = %Δ Quantity Demanded ÷ %Δ Price
PES = %Δ Quantity Supplied ÷ %Δ Price
YED = %Δ Quantity Demanded ÷ %Δ Income
XED = %Δ Quantity Demanded of Good A ÷ %Δ Price of Good B
Price elasticity of demand is elastic when the value is greater than 1, inelastic when it is less than 1, and unitary when it equals 1. Determinants include the availability of substitutes, the proportion of income spent on the good, whether it is a necessity or luxury, and the time period considered. The key revenue rule is that when demand is elastic, a price fall raises total revenue; when demand is inelastic, a price rise raises total revenue.
当需求价格弹性大于 1 时为富有弹性，小于 1 时为缺乏弹性，等于 1 时为单位弹性。决定因素包括替代品的可获得性、该商品支出占收入的比例、是必需品还是奢侈品，以及考察的时间长短。关键的收入法则是：需求富有弹性时，降价使总收益上升；需求缺乏弹性时，涨价使总收益上升。
Income elasticity of demand distinguishes normal goods, which have a positive YED, from inferior goods, which have a negative YED. Among normal goods, those with YED greater than 1 are luxuries and those between 0 and 1 are necessities. Cross elasticity of demand is positive for substitutes and negative for complements, and its size indicates how closely the two goods are related.
需求收入弹性把 YED 为正的正常品与 YED 为负的劣等品区分开。正常品中，YED 大于 1 的是奢侈品，介于 0 与 1 之间的是必需品。需求交叉弹性对替代品为正，对互补品为负，其数值大小反映两种商品关系的紧密程度。
Elasticity also determines tax incidence. When demand is inelastic relative to supply, consumers bear most of an indirect tax; when demand is elastic, producers bear more. A perfectly inelastic supply curve, for example a fixed stock of land, means the whole burden can fall on the seller.
弹性也决定税收归宿。当需求相对于供给更缺乏弹性时，消费者承担间接税的大部分；当需求富有弹性时，生产者承担更多。完全无弹性的供给曲线（例如固定数量的土地）意味着全部税负可能落在卖方身上。
6. Market Failure and Allocative Efficiency | 市场失灵与配置效率
Allocative efficiency occurs where price equals marginal cost, meaning the value consumers place on the last unit equals the cost of the resources used to produce it. Market failure exists whenever the free market fails to achieve allocative efficiency, resulting in a misallocation of resources and a welfare loss, usually shown as a deadweight loss triangle.
配置效率出现在价格等于边际成本之时，即消费者对最后一单位商品的评价等于生产该单位所用资源的成本。只要自由市场未能实现配置效率，就存在市场失灵，导致资源错配与福利损失，通常用无谓损失三角形表示。
- Negative externalities: spillover costs to third parties, such as pollution. 负外部性：对第三方造成的外溢成本，如污染。
- Positive externalities: spillover benefits to third parties, such as education or vaccination. 正外部性：对第三方产生的外溢收益，如教育或疫苗接种。
- Merit goods: under-consumed because of information failure. 优值品：因信息失灵而消费不足。
- Demerit goods: over-consumed because of information failure and negative externalities. 劣值品：因信息失灵和负外部性而过度消费。
- Public goods: non-rivalry and non-excludability create the free-rider problem. 公共品：非竞争性与非排他性导致搭便车问题。
- Common access resources: rival but non-excludable, leading to overuse and depletion. 共有资源：竞争性但非排他性，导致过度使用与枯竭。
- Monopoly power, factor immobility and inequity in income distribution. 垄断势力、要素流动障碍和收入分配不公平。
Distinguish private costs and benefits from external costs and benefits, and social cost as the sum of private and external cost. A diagram is only awarded full marks when the welfare loss is shaded and the label states the divergence between marginal social cost and marginal social benefit.
要区分私人成本与收益、外部成本与收益，社会成本等于私人成本加外部成本。只有在图中标出并阴影化福利损失，并说明边际社会成本与边际社会收益之间的偏离时，图形才能得满分。
7. Government Intervention and Government Failure | 政府干预与政府失灵
Governments intervene to correct market failure, to redistribute income and to influence macroeconomic performance. The main microeconomic tools are indirect taxes, subsidies, tradable pollution permits, regulation, information provision, direct provision and price controls.
政府干预的目的是纠正市场失灵、再分配收入以及影响宏观表现。主要微观工具包括间接税、补贴、可交易排污许可、管制、信息提供、直接提供和价格控制。
| Tool | 工具 | Used to correct | 用于纠正 | Typical limitation | 典型局限 |
| Indirect tax 间接税 | Negative externalities 负外部性 | Regressive; demand inelastic 累退性；需求缺乏弹性 |
| Subsidy 补贴 | Positive externalities 正外部性 | Opportunity cost of tax revenue 税收的机会成本 |
| Maximum price 最高限价 | Exploitation of consumers 消费者被剥削 | Shortages, black markets 短缺、黑市 |
| Minimum price 最低限价 | Low producer incomes 生产者收入过低 | Surpluses needing storage 过剩需储存 |
| Regulation 管制 | Information failure 信息失灵 | Compliance and enforcement costs 合规与执法成本 |
Government failure occurs when intervention creates a net welfare loss and makes the allocation of resources worse rather than better. Common causes are unintended consequences, imperfect information, administrative costs, regulatory capture, and the law of unintended consequences created by conflicting objectives.
政府失灵是指干预造成净福利损失，使资源配置变得更糟而非更好。常见原因包括意外后果、信息不完全、行政成本、监管俘获，以及多重目标冲突带来的非预期结果。
Useful evaluation phrases include the scale of the market failure, the elasticity of demand in the affected market, whether the tax revenue is ring-fenced, and the time lags between identifying a problem and implementing a policy.
有用的评估用语包括：市场失灵的规模有多大、相关市场的需求弹性如何、税收收入是否专款专用
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