Why are hours fixed?

A job advertisement makes an initial offer of terms for a contract. A typical job advertisement describes the job, and something about the qualities and qualifications of the candidates that the advertiser thinks are suitable to fill it. Apart from legally required statements about avoiding discrimination in the selection process, the only other things an advertisement usually contains are statements about pay, other remuneration, hours of work and holiday (or vacation) allowances. These statements may be vague (‘generous remuneration package’, ‘full-time’) or they may be precise, but advertisements that omit them altogether are rare. More often than not, firms are concerned that the people they employ work for a specified number of hours per week, for a specified number of weeks per year. In addition, many contracts specify when in the week those hours will be, although the question of when in the year the weeks will be is usually subject to negotiation. These are the aspects of the work contract that create the concept of absenteeism.

Indeed, one could argue that firms are primarily responsible for creating their own absence problems, because they insist that workers turn up to work at specified times. If firms did not do this, they could not complain that the workers are violating their contracts when they do not turn up when required to do so by their contract.