Labour markets are substantially affected by growth or recession in world trade. Industrial restructuring e.g. from heavy, male dominated industries to lighter, information-based and service to customers oriented industries where women for various reasons are about to compete better. Changes in technology substantially affect jobs. Employers may need fewer staff and the skills required of computer literate employees take on greater significance. Those who are not computer literate may indeed be excluded from a significant area of employment growth.
Management become less able to treat labour as individual, replaceable units.
Collectively negotiated and regulated wage structures may also apply to the individual who, whilst entering into an employment contract as an individual and indeed not necessarily a trade union member, becomes subject to the terms and conditions of employment agreed between an employer and a trade union for that class of employees e.g. railway workers. There is a ratchet effect - always upward from such pay comparability arguments. There are internal labour market effects also.