Self-determined work hours: what influences the individual's choice and can choice be related to health and well-being?

Project leader

Funding source

Forte - Swedish Research Council for Health, Working Life and Welfare

Project Details

Start date: 01/01/2007
End date: 31/12/2008
Funding: 1285000 SEK


In Sweden, it has become common with computerized systems that allows the employer to dynamically control the labor requirements for different days and times of the day by planning for periods of about a month. For workers, this often gives a certain ability to decide their own working hours during the period, as long as the employer's need are met.

We know very little about what working hours looks like when they can be influenced by individuals' desires and needs and the present pilot study had a clear descriptive objective.

There were large individual differences in the prevalence of different shift sequences. The fact that evening types could shift their working hours compared with morning types; however, indicate that individual preferences to some extent could be met. The prevalence of extreme shift combinations (eg, five consecutive night shifts) was low. However, it was common with evening shifts followed by morning shifts, and the incidence was related to insufficient sleep and low satisfaction with work hours, suggesting that working hours could not be fully adapted to suit individual needs. 19% of the subjects were dissatisfied and 62% were satisfied with the ability to influence working hours. There is a great need for larger studies to adjust for the structural differences between job sites, night work / days only, full / part-time and longitudinal studies in which individual differences can be fully controlled and more acute effects of different working arrangements studied over time.

The first study includes an analysis of all the working hours of nurses in a hospital over 2 years with a total of 157,576 shifts spread over 1085 subjects. The data included both the desired working hours, and the actual outcome. The analysis is purely descriptive and includes individuals with at least 100 shifts and = 30h/week (n = 398).

The second study involving 216 nurses, 155 telephone operators and 56 police officers (excluded due to abnormal conditions) that responded to a questionnaire and provided transcripts of their working hours over six months (n = 427). The response rate to the questionnaire was 67% (n = 284). A total of 231 people (62%) had reliable data, and responded to the questionnaire (83% women, mean age 44 ± 10 years).

The results from Study 1 reveal large individual differences in the presence of different shift sequences in the schedules. Most (88%) had sequences with evening shift followed by morning shifts, which means a short rest time in your schedule, but the incidence varied from 0.1% to 22% between individuals. The presence of long night-shift sequences was low: only 62 individuals (16%) had sequences of four consecutive night shifts and 13 (3%) individuals sequences of five night shifts.

In study 2, there were many differences (p <.001) in how the working hours with respect to the workplace, part-time/full-time work and whether night work occurred in the schedule. For the whole group, 62% were satisfied or very satisfied with the opportunity to influence their working hours, and 19% were dissatisfied.

Dividing the subjects into morning- and evening types showed that evening types more likely worked between 21-06h (p <.001). Kendal tau correlations (p <.01) also showed that evening types to a lesser degree (r-.24) worked the early shift (starting before 0730h). Increased frequency of night shifts (r =. 14) correlated with increased satisfaction with working hours and morning work decreased satisfaction (r =-. 16). The incidence of sequences with evening shifts before morning shifts reduced satisfaction (r =-. 19) and correlated negative with perceived sufficient sleep (r =-. 19). However, there was no reliable relation to subjective health. The correlations were modified if by working night/part-time and differed between the work sites.

Last updated on 2017-24-03 at 12:53