How many people are willing and able to work in different industries and occupations? This question refers to the supply of labour.

The labour supply curve

The labour supply curve for any industry or occupation will be upward sloping. This is because, as wages rise, other workers enter this industry attracted by the incentive of higher rewards. They may have moved from other industries or they may not have previously held a job, such as housewives or the unemployed. The extent to which a rise in the prevailing wage or salary in an occupation leads to an expansion in the supply of labour depends on the elasticity of labour supply.

Key factors affecting labour supply

The supply of labour to a particular occupation is influenced by a range of monetary and non-monetary considerations.

1. The real wage rate on offer in the industry itself – higher wages raise the prospect of increased factor rewards and should boost the number of people willing and able to work
2. Overtime: Opportunities to boost earnings come through overtime payments, productivity-related pay schemes, and share option schemes and financial discounts for employees in a certain job.
3. Substitute occupations: The real wage rate on offer in competing jobs is another factor because this affects the wage and earnings differential that exists between two or more occupations. So for example an increase in the relative earnings available to trained plumbers and electricians may cause some people to switch their jobs. In recent times, the British media has been fond of stories of people leaving jobs in academia (including high level university research) and moving in household services because the basic rates of pay and potential earnings are so much greater.
4. Barriers to entry: Artificial limits to an industry’s labour supply (e.g. through the introduction of minimum entry requirements or other legal barriers to entry) can restrict labour supply and force average pay and salary levels higher – this is particularly the case in professions such as legal services and medicine where there are strict “entry criteria” to the professions. Indeed these labour market barriers are partly designed to keep pay levels high as well as being methods of maintaining the quality of people entering these professions

 

The length of time it takes to qualify as an architect restricts the labour supply and keeps salaries high

1. Improvements in the occupational mobility of labour: For example if more people are trained with the necessary skills required to work in a particular occupation
2. Non-monetary characteristics of specific jobs – these can be important – they include factors such as the level of risk associated with different jobs, the requirement to work anti-social hours or the non-pecuniary benefits that certain jobs provide including job security, opportunities for promotion and the chance to live and work overseas, employer-provided in-work training, employer-provided or subsidised health and leisure facilities and other in-work benefits including occupational pension schemes
3. Net migration of labour – the UK is a member of the European Union single market that enshrines free movement of labour as one of its guiding principles. A rising flow of people seeking work in the UK is making labour migration an important factor in determining the supply of labour available to many industries – be it to relieve shortages of skilled labour in the NHS or education, or to meet the seasonal demand for workers in agriculture and the construction industry

Compensating wage (pay) differentials

Wage differentials in part act as a compensation for people who have to work unsocial hours or who are exposed to different degrees of risk at work, both in the short term and long run. Some jobs require a wage-rate that encompasses this risk premium – so workers in the North Sea Oil industry expect a higher return to adjust for the inherent dangers of their work.

Elasticity of labour supply

The elasticity of labour supply to an occupation measures the extent to which labour supply responds to a change in the wage rate in a given time period. In low-skilled occupations we expect labour supply to be elastic. This means that a pool of readily available labour is employable at a fairly low market wage rate. Where jobs require specific skills and lengthy periods of training, the labour supply will be more inelastic. It is hard to expand the workforce in a short period of time when demand for workers has increased.

In many professions there are artificial barriers to the entry of workers. Examples include Law, Accountancy and Medicine. The need for high level educational qualifications makes the supply of newly qualified entrants to these occupations quite inelastic in the short run and is one reason why these workers may earn a higher real wage than average salaries.

The work-leisure trade off

Once somebody has entered the labour force how many hours will they choose to work?
For many people, the hours they work are fixed by their employers and they have little or no flexibility in the total number of hours they supply. But the majority of workers have an opportunity at some point to work additional hours, or perhaps switch from a full-time job to a part-time position, a. And the official data probably understates the true number of people who are “moonlighting” and working in a second or third job because of the rapid expansion of the shadow economy which had encouraged the expansion of a shadow labour force.

Often employers adjust the number of hours of work available to meet their employees’ preferences. Over seven million people are now in part-time employment and much of this growth in part-time jobs has been sustained because it meets the preferences of people looking for greater flexibility in their working arrangements.

Economic theory would suggest that the real wage is a key determinant of the number of hours. The real wage is the money wage rate adjusted for changes in the price level and it measures the quantity of goods and services that can be bought from each hour worked. An increase in the real wage on offer in a job should lead to someone supplying more hours of work over a given period of time, although there is the possibility that further increases in the going wage rate might have little effect on an individual’s labour supply. Indeed, there is the possibility of a backward-bending individual labour supply curve. This is illustrated in the next diagram.

 

 

Two distinct individual labour supply curves are shown. In the first curve, higher real wages do lead to an increase in the number of extra hours supplied, although the rate at which the individual is prepared to give up their leisure time and work longer hours diminishes as the real wage rises. But the labour supply curve meets the standard prediction that higher wages attract people to work longer hours. In the second curve, for most of the range of real wages, the same prediction holds true, but when as real wages step upwards, eventually an individual may choose to actually work fewer hours (ceteris paribus) giving us what is sometimes termed a “backward bending” labour supply curve.

Income and substitution effects

To understand why this might happen we consider the income and substitution effects that arise from a change in the real wage being paid to an individual worker. We start with the income effect.

• The income effect: Higher real wages increase the income that someone can earn from a job, but they also mean that the time that must be spent at work to earn sufficient to pay for a particular product declines. Put briefly, higher pay levels mean that a target real wage can be achieved with fewer hours of labour supply. So this income effect might persuade people to work less hours and enjoy extended leisure time.
• The substitution effect: The substitution effect of a higher wage rate should unambiguously give people an incentive to work extra hours because the financial rewards of working are raised, and the opportunity cost of not working (measured by the wages given up when people opt for leisure instead) has increased.

With the income and substitution effects working in opposite directions, there is no hard and fast prediction about whether people will choose to increase their labour supply as real wages increase. Are the income and substitution effects different for male compared to female workers? What about younger workers entering the labour market for the first time who are looking to save to finance a deposit on a house or to fund other major items of spending? How might people closer to retirement age respond to changes in real wages? What of workers in households where at least someone else is in paid employment compared to a household where there is only one main “breadwinner”?

The available empirical evidence for the UK labour market is mixed, indeed some analysts believe that in aggregate, the income and substitution effects effectively cancel each other out so that real wages have no impact on the individual labour supply!