Shift predictability may combat negative effects of shiftwork; e.g., working time control moderates the effects of long-working hours on health/sickness absence. In some contexts, however, operational demand becomes an overarching principle, with predictability for the employee sacrificed. We propose that unpredictability negatively affects strain/health, attitudinal and behavioural outcomes, and undermines the use of fixed-hours shifts and flexible work arrangements (FWAs) which are commonly used to counteract the well-known consequences of shiftwork.
Police officers/staff (N=3238) in four representative UK forces working variable/8-hour fixed shifts were surveyed. Measures were: shift unpredictability (e.g. detained at end of shift); perceived stress; sleepiness; work-home conflict; cardiovascular/digestive health; coping behaviour; absence; satisfaction; and demographic variables. As well as direct/mediation effects, the moderating effects of fixed shifts, FWAs and nightwork were examined.
Unpredictability was related to greater work-home conflict, perceived stress, digestive health problems and lower shift satisfaction. Nightworking was a persistent source of strain and digestive health problems. Neither fixed shifts nor FWA moderated the effects of unpredictability on outcomes.
As well as being self-reported, cross-sectional data, our data may be unique to police culture e.g., why officers choose to stay beyond rostered hours.
Findings extend to other 24/7 frontline services. The assumption that work schedules, whether fixed or variable, and actual time worked are consistent is challenged. All shift patterns are susceptible to involuntary, unpredictable variation with additional strain/health implications.
The study adds to the taxonomy of work scheduling by including often unseen intrusions on working time.