The system is designed to take advantage of the fact that, in the majority of cases, any payroll run is pretty much like the previous run.
Initially, each employee is set up with what is regarded as the 'normal' situation for a pay run. Their standard time and rate are entered as are any deductions or other aspects. For those who have no regular amounts paid and each run is different, the basic pay record can be entered in readiness for the pay runs.
When a payroll is run, this basic information is copied from the staff record into the current payroll record for any employee who is included in the pay run. The base starting point is then edited by changing hours worked or adding overtime or entering sickness or holiday records. This makes running a payroll very much quicker than starting from scratch each time.
For those companies that pay their staff pretty much the same each month, as in the case of salaried office workers and managers, there are usually no changes to be made. For those staff with overtime or shift payments that vary, it makes the job much easier having the base from which to enter any changes.
Obviously in the case of Sickness and Holiday, these records will always need to be entered.