More words have been written about the effects of computers on employment than on almost any other topic related to IT. The subject is one that attracts statistics as management and labour each strive to heap up evidence to overwhelm the other; but other people's statistics breed suspicion not trust. This chapter will not bury the subject under a mountain of obsolescent and disputable figures; it will attempt instead to present the principal factors involved.

No manager sets out with the prime aim of creating unemployment. The main reason for using IT is to reduce the unit cost of manufacturing some product or providing some service. When it is a matter of slimming a public bureaucracy, almost everyone speaks out fearlessly in favour of drastic economies. In other fields, senior managers find it prudent to present their costcutting proposals as ways of increasing productivity. That beguiling word makes it seems reactionary or irrational to oppose so eminently desirable an objective. Who can argue in favour of lower productivity?

Productivity is no more than a ratio of some input to some output, and measures the consumption of any resource used to create a product or a service. We can speak of the productivity of a raw material, or of a piece of machinery, but most often the word is used without a qualifying adjective and then refers to the use of labour.