Data-Driven Working-Hour Patterns and Accident Risk
Summary
This cohort study tracked over 4,400 hospital employees in Finland between 2008 and 2018, linking payroll data on working hours with national accident records. Researchers used cluster analysis to identify six weekly work-hour patterns. Employees whose weeks included long shifts (over 12 hours), late-night work, and “quick returns” with less than 11 hours between shifts had a higher risk of occupational accidents. Compared with the lowest-risk schedules, the riskiest patterns increased accident risk by about 30%.
Why It Matters For Night Shift Workers and Night Owls
For people working nights, this study shows that it’s not only how tired you feel — the way shifts are structured directly affects safety. When schedules include back-to-back long nights or too little time off between shifts, the chance of accidents goes up. While the study focused on hospital staff, the same lesson applies broadly: recovery time matters. Advocating for schedules that limit quick returns and spread out long shifts can reduce mistakes and injuries in any 24/7 job.
Notes
Safety Science (2022).