Biology and Shift-Worker Desires

shift-work clock

There is no perfect shift-system. But there are a few best practices we can use when planning schedules. One of those rules is to rotate shifts clockwise. For most people, rotating forward is easier because it matches some of our biological circadian rhythms which have a tendency to naturally move forward. A few other circadian rhythms follow a pattern slightly longer than 24 hours.  Rotating forward catches your shifts up with your greater than 24 hour circadian rhythms.

A recent study[1] showed that biologically incompatible backward rotating schedules are associated with greater absenteeism rates and that if you move from counterclockwise to clockwise rotating schedules, you could reduce absenteeism by 10%.

In spite of the organizational benefit of reduced absenteeism, shift-workers may prefer biologically incompatible schedules if it gives them longer consecutive periods off duty, especially after night shifts[1].  Without the extended breaks from work, many shift-workers will reduce their exposure to shift-work and increase their useable leisure time by calling in sick.  Thereby causing the organization to forfeit the 10% reduction in absenteeism.

From this example, we can pull a few best practices for shift patterns:

  • Rotate clockwise
  • Provide as many consecutive days off as possible
  • Provide the consecutive days off after the night shift(s) in the rotation


Reference

[1] Frick, B., Simmons, R., & Stein, F. (2018).  The cost of shift work: Absenteeism in a large German automobile plant.  German Journal of Human Resource Management, 32(3-4), 236-256.