📚 IB & CIE Economics: Labour Market | IB & CIE 经济：劳动力市场考点精讲
The labour market is where households supply their labour in exchange for wages from firms that demand it. Understanding the forces that determine wages and employment levels is essential for IB and CIE Economics. This article synthesises the crucial concepts, theories, and evaluation points you need for your exams.
劳动力市场是家庭提供劳动力、企业以工资作为回报的市场。理解决定工资和就业水平的力量对 IB 和 CIE 经济学至关重要。本文综合了考试所需的关键概念、理论与评估要点。
1. Overview of the Labour Market | 劳动力市场概述
A labour market consists of the demand for labour by employers and the supply of labour by workers. It can be perfectly competitive or imperfect. Wages act as the price, and employment is the quantity exchanged.
劳动力市场由雇主对劳动力的需求和劳动者对劳动力的供给构成。它可以完全竞争，也可以是不完全竞争。工资是价格，就业量是交易量。
2. Demand for Labour: The Marginal Revenue Product Theory | 劳动需求：边际收益产量理论
The firm’s demand for labour is a derived demand, meaning it stems from the demand for the good or service the labour produces. In a profit-maximising setting, a firm hires labour up to the point where the marginal revenue product of labour (MRPₗ) equals the marginal cost of labour (MCL).
厂商对劳动力的需求是一种引致需求，即它源于对劳动力所生产商品或服务的需求。追求利润最大化的厂商会雇用劳动力直至劳动的边际收益产量 (MRPₗ) 等于劳动边际成本 (MCL)。
MRPₗ = MPₗ × MR
MRPₗ = MPₗ × MR
MPₗ is the additional output from hiring one more worker, and MR is the additional revenue from selling that extra output. Due to diminishing marginal returns, the MRP curve slopes downward.
MPₗ 是多雇用一个工人所增加的产量，MR 是出售额外产出所带来的收入。由于边际报酬递减，MRP 曲线向下倾斜。
In a perfectly competitive product market, MR equals price, so MRPₗ = MPₗ × P. In imperfect product markets (e.g. monopoly), MR is less than price, so the MRP curve is steeper.
在完全竞争的产品市场上，MR 等于价格，因此 MRPₗ = MPₗ × P。在不完全竞争产品市场 (如垄断) 中，MR 低于价格，因此 MRP 曲线更陡峭。
3. Determinants of Labour Demand | 劳动需求的决定因素
Changes in MRP can shift the demand curve for labour. Key determinants include productivity of labour, the price of the final good, non-labour factor costs (e.g. capital), and the firm’s revenue including subsidies or changes in demand for the final product.
MRP 的变化会移动劳动需求曲线。关键决定因素包括劳动的生产率、最终产品的价格、非劳动要素成本 (如资本) 以及厂商收入，包括补贴或最终产品需求变化。
If a firm can substitute capital for labour easily, a rise in the wage rate may cause a greater reduction in labour demanded. Additionally, an increase in demand for the final good shifts the MRP curve rightward.
如果企业能轻易用资本替代劳动，工资率上升可能使劳动需求大幅减少。此外，最终产品需求增加会使 MRP 曲线向右移动。
Labour demand also depends on the price elasticity of demand for the final product: the more elastic the product demand, the more elastic the derived demand for labour.
劳动需求还取决于最终产品需求的价格弹性：产品需求弹性越大，引致的劳动需求弹性也越大。
4. Supply of Labour | 劳动的供给
Individual labour supply decisions are based on the trade-off between work and leisure. The opportunity cost of leisure is the wage rate forgone. The substitution effect of a wage rise encourages more hours worked, while the income effect may reduce work as higher income allows more leisure.
个人的劳动供给决策基于工作与闲暇的权衡。闲暇的机会成本是放弃的工资率。工资上升的替代效应鼓励增加工作时间，而收入效应可能因收入提高而减少工作，选择更多闲暇。
The backward-bending individual labour supply curve emerges when the income effect outweighs the substitution effect at high wage levels.
当工资水平高到收入效应超过替代效应时，个体劳动供给曲线会向后弯曲。
The market supply of labour for a particular occupation is generally upward-sloping, reflecting that higher wages attract more workers from other sectors or activities.
特定职业的市场劳动供给通常向上倾斜，反映了较高工资能从其他行业或活动中吸引更多工人。
5. Determinants of Labour Supply | 劳动供给的决定因素
Shifts in the labour supply curve are caused by changes in the size of the working-age population, migration, participation rates, non-wage benefits, barriers to entry (qualifications), and social attitudes towards work.
劳动供给曲线的移动由工作年龄人口规模变化、移民、参与率、非工资福利、进入壁垒 (资格) 以及社会对工作的态度等因素引起。
Better education and training can increase the quality of labour but may reduce short-run supply in a specific low-skill market, shifting the curve leftward. Improved working conditions or higher wages in alternative occupations reduce supply in the current market.
更好的教育和培训可以提高劳动力质量，但可能减少特定低技能市场的短期供给，使曲线左移。另一个职业工作条件改善或工资上升会减少当前市场的供给。
6. Wage Determination in Perfectly Competitive Labour Markets | 完全竞争劳动力市场的工资决定
In a perfectly competitive labour market, many firms compete for workers, and many workers offer identical labour. No single employer or worker can influence the wage rate. The equilibrium wage and employment level are set where labour demand equals labour supply.
在完全竞争的劳动力市场上，许多企业争聘工人，而许多工人提供同质的劳动。任何单个雇主或工人都无法影响工资率。均衡工资和就业水平在劳动需求等于劳动供给处决定。
The firm faces a perfectly elastic supply of labour at the market wage, meaning MCL = average cost of labour (ACL) = W. The firm hires where MRPₗ = W, maximising profit.
企业面临完全弹性的劳动供给，即 MCL = 劳动平均成本 (ACL) = W。企业在 MRPₗ = W 处雇用工人，实现利润最大化。
Shifts in demand (e.g. increased MRP) raise both wage and employment, while shifts in supply (e.g. greater net migration) reduce wages and raise employment.
需求曲线右移 (如 MRP 提高) 会使工资和就业同时上升，而供给曲线右移 (如净移民增加) 则会降低工资并增加就业。
7. Imperfect Labour Markets: Monopsony | 不完全劳动力市场：买方垄断
A monopsony exists when there is a single dominant employer in a labour market. The firm faces the upward-sloping market supply curve, so to hire an additional worker it must raise the wage for all workers. This makes MCL higher than the average wage.
劳动力市场存在买方垄断时，只有一个主要雇主。企业面临向上倾斜的市场供给曲线，因此多雇用一个工人就必须为所有工人提薪，使得 MCL 高于平均工资。
The profit-maximising monopsonist hires where MRPₗ = MCL, then pays the wage determined by the labour supply curve at that employment level. This results in lower employment and lower wage compared to a competitive outcome.
追求利润最大化的买方垄断者在 MRPₗ = MCL 处确定雇用量，然后根据该雇用量在劳动供给曲线上支付工资。与竞争结果相比，这导致更低的就业水平和更低的工资。
Monopsony equilibrium: Wₘ < W_c and Lₘ < L_c
买方垄断均衡: Wₘ < W_c 且 Lₘ < L_c
Monopsony power can arise from geographical isolation, specialised skills, or collusive agreements among a few large employers.
买方垄断力量可能源于地理隔绝、专业化技能或少数大雇主之间的合谋协议。
8. Elasticity of Labour Demand and Supply | 劳动需求与供给弹性
The wage elasticity of labour demand measures the responsiveness of employment to a change in the wage rate: η = (%ΔQₗ) / (%ΔW). It is influenced by the ease of substituting capital for labour, the price elasticity of product demand, the proportion of labour in total cost, and the time period.
劳动需求的工资弹性衡量就业对工资率变化的反应程度：η = (%ΔQₗ) / (%ΔW)。它受资本替代劳动的难易程度、产品需求的价格弹性、劳动在总成本中的比例以及时间跨度影响。
The wage elasticity of labour supply reflects how willing workers are to change their hours or enter an occupation when wages change. It is higher in the long run and for low-skilled jobs with minimal entry barriers.
劳动供给的工资弹性反映工人对工资变化时改变工作时间或进入某职业的意愿。长期弹性和进入壁垒低的低技能工作的弹性更高。
Inelastic labour supply (e.g. highly specialised surgeons) means a demand increase will raise wages significantly but have a relatively small effect on employment.
劳动供给缺乏弹性 (如高度专业的外科医生) 意味着需求增加会大幅提升工资，但对就业的影响相对较小。
9. Wage Differentials: Causes and Types | 工资差异：原因与类型
Workers are not all paid the same. Compensating differentials explain higher pay for jobs with unpleasant risks, unsocial hours, or dangerous conditions. Human capital differences—education, training, and experience—also generate significant wage gaps.
并非所有工人都获得相同报酬。补偿性差异解释了工作带有不愉快风险、非正常工作时间或危险条件为何工资更高。人力资本差异——教育、培训和经验——也产生了显著的工资差距。
Other causes include trade union power, monopsony employers, geographical immobility, occupational immobility, and discrimination. Differences in MRP due to varying productivity also lead to diverging wages across sectors.
其他原因包括工会力量、买方垄断雇主、地理上的不流动性、职业不流动性以及歧视。由于生产率差异导致的 MRP 不同也会造成行业间工资分化。
Efficiency wage theory suggests that paying above the market-clearing wage can boost worker productivity, reduce turnover, and attract higher-quality applicants, thereby perpetuating wage differentials.
效率工资理论提出，支付高于市场出清的工资可以提高工人生产率、减少流失并吸引更优质的求职者，从而维持工资差异。
10. Trade Unions and Collective Bargaining | 工会与集体谈判
Trade unions aim to improve wages, working conditions, and job security for their members through collective bargaining. By restricting labour supply (e.g. closed shop, licensing) or raising demand (e.g. improving productivity, advocating for the product), unions can push wages above the competitive level.
工会旨在通过集体谈判为其会员提高工资、改善工作条件和就业保障。通过限制劳动供给 (如排外性雇佣制、执业许可) 或提高需求 (如提高生产率、为产品游说)，工会能将工资推高到竞争水平之上。
If a union successfully raises wages in a competitive market, employment falls, creating classical unemployment. However, in a monopsony, a union-set wage floor can counter the employer’s market power and increase both wages and employment.
在竞争性市场上，工会成功提升工资会导致就业减少，产生古典失业。然而在买方垄断中，工会设定的工资下限可以抑制雇主的市场力量，同时提高工资和就业。
The extent of union power depends on membership density, legal support, the elasticity of labour demand, and the state of the economy. Evaluation must consider possible negative effects on competitiveness and firm closures.
工会的力量取决于会员密度、法律支持、劳动需求弹性和经济状况。评估时必须考虑对竞争力和企业倒闭可能带来的负面影响。
11. Minimum Wage Legislation | 最低工资立法
A statutory minimum wage sets a price floor in the labour market. In a perfectly competitive market, a minimum wage above the equilibrium causes excess supply of labour (unemployment) and reduces the quantity of labour demanded. The magnitude depends on the elasticity of labour demand.
法定最低工资在劳动力市场中设置了价格下限。在完全竞争市场上，高于均衡的最低工资会导致劳动供给过剩 (失业) 并减少劳动需求量。影响幅度取决于劳动需求的弹性。
In a monopsony, a well-set minimum wage can act as a corrective tool. By raising the wage to the competitive level, it can eliminate the monopsonist’s incentive to restrict employment and thus raise both pay and jobs, as long as the minimum does not exceed the competitive wage too far.
在买方垄断中，设置得当的最低工资可作为纠正工具。将工资提升至竞争水平，可以消除买方垄断者限制就业的动机，从而同时提高工资和就业，只要最低工资不超过竞争工资过多。
Evaluation includes considerations of regional differences, impact on training, potential inflation, and the risk of pushing vulnerable workers into informal sectors. Evidence from many countries suggests small to moderate minimum wages have limited employment effects.
评估包括地区差异、对培训的影响、潜在通胀以及将弱势工人推入非正规行业的风险。许多国家的证据表明，小幅至中等幅度的最低工资对就业影响有限。
12. Discrimination in Labour Markets | 劳动力市场中的歧视
Discrimination occurs when equally productive workers are treated differently based on non-economic characteristics such as gender, ethnicity, age, or disability. This leads to wage differentials and occupational segregation, undermining efficiency.
当生产率相同的工人因性别、种族、年龄或残疾等非经济特征而受到不同对待时，即产生歧视。这会导致工资差异和职业隔离，损害效率。
Taste-based discrimination, modelled by Gary Becker, assumes employers, co-workers, or customers have a distaste for hiring a particular group, leading to lower demand for their labour and hence lower wages. Statistical discrimination occurs when firms use group averages to judge individual applicants, often unintentionally.
由加里•贝克尔模型化的偏好性歧视，假设雇主、同事或顾客对雇用特定群体有厌恶感，从而降低对该群体劳动的需求，导致工资降低。统计性歧视发生在企业利用群体平均水平来判断个人求职者时，通常是无意的。
Anti-discrimination legislation, affirmative action, and transparency in pay are policy responses. However, deep-rooted social norms limit their effectiveness, requiring long-term educational and cultural shifts.
反歧视立法、平权行动和薪酬透明是政策回应。但根深蒂固的社会规范限制了其有效性，需要长期的教育和文化转变。
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