The effect of different work-rest schedules on fatigue and performance of a simulated directory assistance operator's task.

The directory assistance operators' task with a visual display terminal was simulated to determine the preferable work-rest schedule from among the three different work-rest schedules: 30 min of work followed by 5 min break (30-5); 60 min of work followed by 10 min break (60-10); and 120 min of work without any break (120-0). The total working duration was 2 h. The errors made during the work and the subjective responses before and after the working period (2 h) were recorded and analysed. The results showed that the first two work-rest schedules were preferable to the third condition (120-0) as significantly fewer errors were made (p > or = 0.01) when a short break was provided. There was no significant difference (p > or = 0.10) in errors between (30-5) and (60-10) schemes. Fewer before and after subjective responses differed significantly for (30-5) and (60-10) schemes than for the (120-0) scheme. The overall effect of schemes on subjective responses, however, was not statistically significant at the 5% level. Since both (30-5) and (60-10) schemes were found acceptable, the (60-10) scheme is recommended since it is easy to implement, causes fewer breaks and therefore, fewer work interruptions, and leads to fewer total minutes of break.