Trade unions are associations of workers that negotiate with
employers on the pay and working conditions of members of the union. Trade
unions have 3 major objectives; wage bargaining, improvement of working
conditions and the security and health of their members.
There are 2 ways in which a trade union may seek to affect
labour market equilibrium. It may limit the supply of workers into an
occupation or industry (you may legally have to be a member of a certain union
to enter a profession). Also it may negotiate for higher wages for its members.
Restricting Labour Supply
The graph to the left is a normal labour graph for a firm. However if the firm is facing a trade union that limits the amount of labour into the market then the unions will be able to artificially push the wage up.
In this situation the union is effectively trading off higher wages for its members, against a lower level of employment. The people that aren’t a member of the union, but would be happy to supply their labour at w*, can’t (as they are not a member of the compulsory union) and so remain unemployed, imposing a cost on society.
The extent of the trade off depends on the elasticity of demand for labour. When demand for labour is more elastic the wage increase is lower, whereas with inelastic demand for labour the wages rises more than that of elastic demand for labour.
Negotiating Wages
Alternatively a trade union can attempt to negotiate higher wages for its members. If they succeed then the wage will be higher but the level of unemployment will be also higher as the firm hires less labour.
Again the elasticity of demand for labour affects the outcome, when demand is more inelastic the effect on the quantity of labour employed is less than when demand is more elastic. This means that when demand for labour is inelastic unemployment will be lower (than when demand for labour is elastic). This is shown in the graph below. We is the natural equilibrium for labour, however the trade union has negotiated the waged to W*, at DL1 (inelastic demand for labour) there is less unemployment that at DL2 where unemployment is higher.
Job
Security
Workers will have more job security if they are a member of a
union as the union will take legal action. From a firms point of view this can
lead to an increase in motivation as workers feel secure and this leads to an
increase in productivity.
Labour
Market Flexibility
Unions have affected the degree of flexibility of the labour market;
their actions limit the entry of workers into a market.