Evaluation of an 8 hour versus a 12 hour shift roster on employees at a power station

Several studies exist that have conducted research into the effects of diff erent shiftwork patterns on the individual, especially regarding 8 and 12 h rosters. The findings of these studies have been largely supportive of lon ger shifts, however, the effects on work performance are not as clear cut. This study aimed to examine the changeover from an 8 h roster to a 12 h ros ter in a power station via monitoring on-shift performance, general health and well-being, sleep and mood behaviour, as well as absence and accident d ata. Results suggest that the domestic and social life of workers was marke dly improved under the 12 h roster. Improvements in physical health, sleepi ng behaviour and mood state of employees were also documented. On-shift per formance measures showed an increase in error rates at the end of a 12 h sh ift. Ways of reducing the risk of error towards the end of a 12 h shift sho uld be explored. The results of this study suggest that 12 h shifts are a v alid alternative to 8 h shifts in this particular workplace, although tasks that require error-free activities should not be performed towards the end of a 12 h shift. (C) 1999 Elsevier Science Ltd. All rights reserved.