A surgeon earns many times what a care worker earns, though both keep people alive and the care worker may work longer hours in worse conditions. Nothing in the moral value of the work explains the gap. Wages are prices, set in markets, and they are determined by what employers are willing to pay for the output a worker produces and by how many people are able and willing to do the job. Understanding that is uncomfortable but it is the entire explanation.
The demand for labour comes from employers and is a derived demand: nobody wants workers for their own sake, only for what they produce. It therefore rises when demand for the final product rises, when labour becomes more productive, and when the price of substituting capital rises. The supply of labour comes from workers and depends on the wage on offer, the qualifications and training required, the length of training, working conditions, and how attractive alternative occupations are. The wage settles where the two meet.
Wage differences between occupations follow directly. Jobs requiring long or expensive training have restricted supply, because few people are qualified, so the wage must be high enough to compensate for the years of study and forgone earnings. Dangerous, unpleasant or unsocial work commands a compensating differential, though only where workers have alternatives. Highly productive workers, or those whose output sells for a high price, are worth more to an employer. And where a job needs few skills and almost anyone can do it, supply is large and the wage is low regardless of how socially valuable the work is.
An individual's choice of job depends on more than the wage. Wage factors include the basic pay, overtime, bonuses and commission. Non-wage factors include working hours and holidays, job security, the chance of promotion and training, working conditions and safety, the distance to travel, fringe benefits such as a pension or company car, and job satisfaction. A worker may choose a lower-paid job because it is secure, interesting or close to home, which is why wages alone do not explain where people work.
Wages also differ between groups of workers. Skilled workers usually earn more than unskilled workers, because fewer people can do the job and each produces more. Pay differs by sector: tertiary sector jobs in finance or technology often pay more than primary sector jobs in farming. Public sector workers, employed by the government, often have more job security and better pensions but may earn less than similar workers in the private sector, where pay is set by firms seeking profit. Discrimination, such as paying women less than men for work of equal value, is illegal in many countries but still contributes to gaps in pay. And government policy, through minimum wages and public sector pay decisions, changes wages directly.
Wage differential questions are marked on both sides of the market, and most answers give only one. An answer explaining that surgeons are highly skilled has given the supply side and stopped. Add the demand side, that the value of what they produce is high, and the answer is complete. Say 'supply is limited because...' and 'demand is high because...' explicitly and the structure earns the marks.
Trade union
An organisation of workers that negotiates collectively with employers over pay, conditions and job security on behalf of its members.
A trade union exists because an individual worker bargaining alone against an employer has little power, while all the workers bargaining together have a great deal. Collective bargaining is the process by which a union negotiates on behalf of all members at once. Unions pursue higher pay, better and safer conditions, shorter hours, job security and training, and they represent individual members in disputes. Their strength depends on how large a share of the workforce they represent, how easily the employer could replace them, how profitable the employer is, and the legal framework governing industrial action.
Whether a pay rise is affordable for the employer
A firm employs 200 workers at $30,000 a year and makes an annual profit of $2.4 million. A union demands a 10% pay rise. Calculate the extra wage cost and the effect on profit. Then calculate the productivity gain that would make the rise self-financing.
The demand for labour is described as a derived demand. This means:
Which factor would most increase a trade union's bargaining power?
A national minimum wage is a legal lower limit on the hourly wage. It raises the pay of the lowest-paid workers and reduces poverty among those in work, and it may encourage people to take jobs rather than stay on benefits. The risk is that, if it is set above the wage the market would pay, firms want to employ fewer workers while more people want to work at the higher wage, so some unemployment may result, especially among young and unskilled workers. How large that effect is depends on how high the minimum wage is set.
Draw a labour market diagram with the wage rate on the vertical axis and the quantity of labour on the horizontal axis. Mark the equilibrium wage. Draw a national minimum wage above it and label the quantity of labour demanded, the quantity supplied and the unemployment that results. On a second diagram, show a rise in the demand for labour and its effect on the wage and employment.
The minimum wage line must be above the equilibrium to have any effect. The gap between the two quantities is the unemployment it may cause.
Division of labour
Breaking production into separate tasks, with each worker specialising in one task.
The division of labour raises output because workers become skilled and quick at their one task, no time is lost moving between jobs, and machinery can be designed for each task. It lowers the cost per unit and makes mass production possible. Its disadvantages are that repetitive work is boring, so motivation and quality can fall; workers with only one narrow skill find it harder to get another job if that task disappears; and if one stage of production stops, the whole line stops.
Labour mobility is how easily workers can change jobs. Occupational mobility is the ability to move between types of work, and it is limited when new skills or qualifications are needed. Geographical mobility is the ability to move to jobs in other places, and it is limited by differences in house prices and rents, family ties, the cost of moving and a lack of information about jobs elsewhere. Low mobility means vacancies and unemployment can exist side by side, which is structural unemployment. Training raises occupational mobility, and help with housing and moving costs raises geographical mobility.
Draw a labour market diagram with the wage rate on the vertical axis and quantity of labour on the horizontal axis, showing demand for and supply of labour meeting at the equilibrium wage. Then show the effect of a trade union successfully negotiating a wage above the equilibrium, marking the number of workers firms wish to employ and the number wishing to work at that wage.
Label the gap between the two quantities. That gap is the excess supply of labour, which is unemployment caused by the wage being above the market-clearing level. Showing it is what turns 'unions can cause unemployment' from an assertion into analysis, and the same diagram serves for a minimum wage.
Marginal revenue product
At A Level the demand for labour is derived precisely rather than described. A profit-maximising firm hires an additional worker whenever that worker adds more to revenue than to cost. The addition to revenue is the marginal revenue product of labour, which is the marginal physical product of the worker multiplied by the marginal revenue earned on the output. The addition to cost, in a competitive labour market where the firm can hire as many workers as it likes at the going wage, is simply the wage. The firm therefore hires up to the point where MRP equals the wage, and the downward-sloping portion of the MRP curve is the firm's demand curve for labour.
MRPL = marginal physical product of labour x marginal revenue Hire until MRPL = wageFor a firm selling in a perfectly competitive product market, marginal revenue equals price, so MRPL = MPP x price. For a price maker, MR is below price and falls with output, so MRPL falls for two reasons at once: diminishing returns and falling marginal revenue. Formulae are not printed in any 9708 paper.
Finding how many workers a firm should employ
A firm sells its output at a constant $5 per unit in a competitive product market. Adding workers one at a time raises weekly output as follows: 1 worker 60 units, 2 workers 130, 3 workers 190, 4 workers 240, 5 workers 276, 6 workers 300. The market wage is $250 a week. Calculate the marginal revenue product of each worker and determine how many to employ.
The MRP theory is elegant but its assumptions are demanding, and the evaluation marks lie in naming them. It requires that a worker's individual output can be measured, which is impossible for most team-based and service work. It requires that output can be valued at a market price, which fails for public services. It assumes the firm maximises profit, and that it has the information to identify MRP at all. It ignores the influence of trade unions, government wage floors, discrimination and custom. The theory explains the broad pattern of wage differentials well and the pay of any particular individual poorly.
Imperfect labour markets
A monopsony is a single dominant buyer of labour, and it changes the analysis fundamentally. Because the monopsonist faces the whole upward-sloping market supply curve of labour, hiring one more worker requires raising the wage, and if it must pay the higher wage to everyone then the marginal cost of labour exceeds the wage. It maximises profit where MRP equals the marginal cost of labour, then pays only the wage the supply curve requires at that level of employment. The result is that both employment and the wage are lower than in a competitive labour market, and workers are paid less than the value of what they produce.
Why a union or minimum wage can raise both pay and employment under monopsony
- A monopsonist faces the market supply curve of labour, so it must raise the wage to attract additional workers.
- Because the higher wage applies to all workers, the marginal cost of labour rises faster than the wage and lies above the supply curve.
- Profit maximisation sets MRP equal to the marginal cost of labour, giving employment below the competitive level.
- The wage paid is read off the supply curve at that employment, so it lies below MRP and below the competitive wage.
- Now a union or a minimum wage imposes a wage floor above the monopsony wage.
- Up to the point where the floor binds, the employer can hire additional workers at that fixed wage, so the marginal cost of labour becomes the wage itself rather than exceeding it.
- With marginal cost of labour now equal to the wage, the firm hires until MRP equals that wage, which is more workers than before.
- Both the wage and employment rise, and the outcome moves towards the competitive result.
This is the single most valuable chain in the topic, because it is the counter-argument to the standard claim that wage floors cost jobs. Whether a minimum wage reduces employment depends on whether the labour market is competitive or monopsonistic, and stating that condition is what reaches the top band.
Practise this chain →Draw a monopsony labour market with the supply of labour curve, the marginal cost of labour curve above it, and the MRP curve sloping down. Mark the profit-maximising employment where MRP meets MCL, and the wage read off the supply curve beneath it. Then add a horizontal wage floor above the monopsony wage and show the new employment level.
The exploitation gap is the vertical distance between MRP and the wage actually paid at the monopsony employment level; shade it. The reason MCL lies above supply is that raising the wage to attract one more worker means raising it for everyone already employed, so the marginal cost includes those inframarginal rises. Candidates who cannot explain why MCL is above supply cannot use this diagram convincingly.
Trade unions raise wages by several distinct routes and the mechanism matters for the employment effect. They may bargain collectively for a wage above the equilibrium, which in a competitive market creates excess supply of labour and reduces employment. They may restrict the supply of labour through qualification requirements or closed shop arrangements, raising the wage by shifting supply left. They may raise the demand for labour by supporting productivity improvements or by campaigning for the product, which raises the wage without any employment cost. And under monopsony they may raise both wage and employment. Union power itself depends on density, the elasticity of demand for the final product, the ease of substituting capital, the share of wages in total costs and the legal framework.
In a monopsonistic labour market, why does the marginal cost of labour exceed the wage?
Transfer earnings and economic rent
Why does a top footballer earn millions when he would play for a fraction of that? The answer divides every worker's earnings into two parts. Transfer earnings are the minimum a worker must be paid to stay in an occupation rather than move to their next best alternative; they are the opportunity cost of keeping that worker. Economic rent is anything earned above that minimum. Because every worker in a market is usually paid the same market wage, those who would have worked for less receive economic rent, while the last worker attracted into the occupation receives almost none.
Economic rent
The part of a factor's earnings above its transfer earnings, which is the minimum payment needed to keep it in its current use.
Splitting earnings into transfer earnings and economic rent
Five workers could be employed in an occupation. The lowest weekly wage each would accept, because of what they could earn elsewhere, is $300, $400, $500, $600 and $700. Employers need all five and pay every worker the same market wage of $700. Calculate total earnings, total transfer earnings and total economic rent.
Draw a labour market with an upward-sloping supply curve and a demand curve meeting at the equilibrium wage. Shade the area below the supply curve up to the equilibrium quantity as transfer earnings, and the area above the supply curve and below the wage as economic rent. On two further diagrams, show a perfectly elastic and a perfectly inelastic supply of labour and label what each area becomes.
With perfectly elastic supply, all earnings are transfer earnings and there is no rent. With perfectly inelastic supply, all earnings are economic rent. Those two extremes are the quickest way to show that the split depends on elasticity.
The split depends above all on the elasticity of supply of labour to the occupation. Where supply is inelastic, because the job needs rare talent, long training or specific qualifications, few people can be attracted in whatever the wage, so a rise in demand raises the wage without adding many workers and most earnings become economic rent. This is why elite sportspeople, leading performers and top surgeons earn so much: demand for their services is high and their supply cannot expand. Where supply is elastic, because many people could do the job, wages cannot rise far above what workers could earn elsewhere and most earnings are transfer earnings. Time matters too: supply to most occupations becomes more elastic in the long run as people train, so rent that looks permanent can be competed away.
The supply of labour to an occupation is perfectly inelastic. Demand for that labour rises. What happens?
The distinction has a policy use. Because economic rent is a payment above what is needed to keep a factor in its use, taxing it does not, in principle, change how much of the factor is supplied. A tax that falls only on rent is therefore efficient: it raises revenue without reducing work or output. This is the argument behind taxes on land values and on very high earnings in occupations with inelastic supply. The practical difficulty is that nobody can observe an individual's transfer earnings, so a tax aimed at rent is likely to take some transfer earnings too, and those workers may then leave the occupation or the country.
Applied context
Minimum wage evidence is the most instructive case in this topic because it did not turn out as the simple model predicted. Introductions and increases of statutory minimum wages across a number of countries have been followed by employment effects far smaller than a competitive labour market model implies, and in some studies no measurable job losses at all. The leading explanations are that many low-wage labour markets have monopsonistic features, that employers absorb the cost through lower turnover and higher productivity rather than through redundancies, and that higher pay raises spending among exactly the households most likely to spend it.
This is the evidence that makes the monopsony chain worth learning. Use it to argue that the employment effect of a wage floor is an empirical question determined by market structure, rather than settled by the competitive diagram.
The labour market applies the firm's marginal logic to the input side, so it depends on the costs and revenue topic for the profit-maximising rule and on market structures for the analysis of a single dominant buyer, since monopsony is the mirror of monopoly. It connects to unemployment, because real-wage unemployment is what the competitive diagram above the equilibrium shows, though that note handles the macro question of the level of unemployment. It runs into equity and redistribution, since wage differentials are the main source of income inequality before tax. And minimum wage policy is a government microeconomic intervention, assessed with the same tools as price floors in goods markets.
9708-3.2 · 9708-7.5 · 9708-7.6 · 9708-8.1 · 9708-8.2 · 9708-9.3
Do you agree that in an imperfect labour market any activity by trade unions damages the interests of workers as a whole? (13 marks)
- Define and frameDefine an imperfect labour market and identify monopsony as the central case. Define 'workers as a whole' explicitly, since it covers union members, non-members and those excluded from employment, and the answer differs between them. Note that 'any activity' is an absolute claim, so a single counter-example defeats it.
- Analysis: the case that unions damage workersUse the competitive diagram: a negotiated wage above equilibrium creates excess supply, so employment falls and those who lose jobs are workers too. Add that insiders gain at the expense of outsiders, that restrictive practices reduce labour mobility, and that industrial action costs members income directly. Note that if higher wages raise costs and the firm is in a competitive product market, it may close or relocate, harming all its workers.
- Analysis: the case that unions benefit workersThis is where the marks concentrate, because the question specifies an imperfect market. Run the monopsony chain in full with a diagram: a wage floor removes the gap between marginal cost of labour and the wage, so both pay and employment rise. Add that unions counter employer bargaining power, secure safer conditions and training, reduce turnover and can raise productivity, so the wage rise may be partly self-financing.
- EvaluationWeigh the conditions rather than balancing lists. Market structure is decisive: the damage case assumes a competitive labour market and the benefit case assumes monopsony, and the question has already told you the market is imperfect. Elasticity of labour demand matters, since a wage rise costs few jobs where demand is inelastic. The size of the rise matters, since a floor above the competitive wage reduces employment even under monopsony. And the empirical minimum wage evidence suggests employment effects are smaller than the competitive model predicts.
- JudgementReject 'any activity' plainly. Union activity damages workers as a whole where the labour market is competitive, where labour demand is elastic and where the wage demand is large relative to productivity. It benefits them where monopsony power exists, where the rise is moderate and where it is matched by productivity gains. Since the question stipulates an imperfect market, the balance leans towards benefit, and the honest conclusion states the wage level at which that reverses rather than asserting a general verdict.
A real question from November 2013, Paper 4. Note the phrase 'workers as a whole', which is doing deliberate work: an answer considering only union members has not addressed the question, since the employment effect falls on those outside the union.
Does a national minimum wage cost jobs?
- The competitive model is unambiguous: a wage floor above equilibrium creates excess supply and reduces employment. The prediction is clear, and where labour markets genuinely are competitive and the floor is set high, it is the right prediction.
- Against that, the empirical record across many countries shows employment effects consistently smaller than the model implies, and often statistically indistinguishable from zero. When a model's central prediction repeatedly fails to appear, the assumptions rather than the evidence are what should be questioned.
- Monopsony is the leading explanation and it reverses the conclusion, since a floor can raise both wage and employment. The condition is that employers have wage-setting power, which is plausible in local labour markets with few employers and in occupations where moving employer is costly.
- Adjustment margins other than employment matter and are usually omitted from student answers. Firms respond through lower staff turnover, reduced training costs, higher effort and productivity, smaller profit margins and modest price rises, all of which absorb the cost without redundancies.
- The level chosen is decisive and is what the argument should really be about. A floor slightly above the monopsony wage raises employment; one far above the competitive wage reduces it. This is why minimum wage debates in practice concern the rate rather than the principle.
- The distributional case is separate from the employment case and often stronger. Even if some jobs are lost, a minimum wage raises income for a large number of low-paid workers, so the policy question is a trade-off between wage gains for many and job losses for few, not a search for a costless option.
The examiner's dividing line here is whether you make market structure the deciding variable. Weak answers assert that minimum wages and unions cause unemployment, using the competitive diagram alone. Strong answers say the effect depends on whether the labour market is competitive or monopsonistic, draw both diagrams, and then say which is more plausible for the market in the question. That single move is worth more than any amount of additional detail.