Background of the Issue
Most police departments have traditionally placed their patrol officers on a 40-hour workweek in which personnel work five consecutive 8-hour shifts, followed by two days off. In recent years, however, an increasing number of law enforcement agencies have moved to some variant of a compressed workweek. Some officers work four 10-hour shifts weekly or three 12-hour shifts (plus a time adjustment to make up the remaining 4 hours of the standard 40-hour workweek). While this trend has been moving apace, few, if any, rigorous scientific studies examining the advantages and disadvantages of these works schedules for officers and their agencies have been completed until now.
The researchers used the most rigorous scientific techniques available: a randomized controlled experiment. The NIJ-funded study was conducted by the Police Foundation.
Overview of the Findings: No Impact on Performance, but Important Impacts on Other Outcomes
The results revealed no significant differences between the three shift lengths on work performance, health or work-family conflict. There were, however, important differences for other outcomes. The 10-hour shift offered certain benefits not associated with 8-hour shifts, and 12-hour shifts had some disadvantages.
Sleep and Fatigue. Significant differences were found in the average amount of sleep officers got across the 8- 10- and 12-hour shifts, but there were no differences in the quality of sleep. Officers working 10-hour shifts averaged significantly more sleep than those working 8-hour shifts. Officers working 12-hour shifts reported greater levels of sleepiness and lower levels of alertness at work than those assigned to 8-hour shifts. Officers on 8-hour shifts averaged significantly less sleep per 24-hour period and worked significantly more overtime hours than those on 10- and 12-hour shifts.
A 10-hour shift may be a good alternative to the traditional 8-hour shift in larger agencies; however, caution is advised when considering 12-hour shifts because of increased levels of sleepiness and lower levels of alertness. Indeed, researchers have noted that people underestimate their levels of fatigue, so officers may be sleepier than they reported while working 12-hour shifts.
In addition, past research has shown increased risks for accidents with increasing number of hours worked. Consequently, caution should be exercised when agency executives consider adopting 12-hour shifts.
Quality of Life. Officers completed several self-report scales as measures of their perceived quality of personal life and work life. The analysis of their responses showed no significant differences among the three shifts on the quality of personal life, but in terms of the quality of work life, officers working 10-hour shifts reported significantly higher quality of work life than those on 8-hour shifts. Officers working the 8-hour shifts in both sites reported the lowest quality of work life. No quality of work life benefits came from the 12-hour shifts. This is consistent with past research in other workplaces showing that those on compressed work schedules tend to rate them favorably or have increased job involvement or satisfaction.
Job Performance. The study focused on factors that are important in police performance, including interpersonal performance, driving safety, shooting performance and self-initiated activity. For all of these measures, there were no statistically significant differences across shift length groups.
The researchers collected departmental data and performance data from simulators to assess officer performance on each of the three shifts.
With regard to self-initiated activities, such as traffic stops and reports completed, some past studies in nursing showed a reduced work effort and a decrease in activities for people on 12-hours shifts. However, in this study, shift length had no impact on the number or quality of police self-initiated activities.
Impact on overtime. The most surprising finding was the reduced overtime of those working 10-hour shifts. This suggests a potential cost saving for agencies that offer alternative work schedules, especially 10-hour shifts in which officers worked an average of 4.78 hours less per two-week period than those on eight-hour shifts.
Officers on 8-hour shifts worked significantly more overtime (more than five times as much as those on 10-hour shifts, and more than three times as much as those on 12-hour shifts). The reduced levels of overtime for those working longer shifts suggest the possibility for cost savings for agencies that use compressed schedules. These findings are consistent with many past studies, but no past study used the randomized controlled trial techniques used in this study and thus seem to have had limited acceptance.
How the Research Was Conducted
To examine the extent to which shift schedules impact performance and safety, health, quality of life, fatigue and extra-duty employment, researchers selected two departments from different regions of the country and with different demographic composition: Detroit (Michigan) Police Department and Arlington (Texas) Police Department. Officers in both agencies were working traditional five 8-hour duty tours and their leaders were interested in examining the pros and cons of other schedule options.
Officers volunteered to participate and agreed to work three types of shifts for 6 months each: 1) five consecutive 8-hour days, 2) four consecutive 10-hour days, and 3) three consecutive 12-hour days. The shifts were day, evening and midnight shifts. The officers were randomly assigned to work the shifts between January 2007 and June 2009.
At the beginning and end of each 6-month period, researchers collected a range of data. Work performance and safety was measured using both laboratory simulations (for shooting and driving) and departmental data on performance. Health, quality of life, sleep, sleepiness, off-duty employment and overtime hours were measured by self-report measures, including surveys, sleep diaries and alertness logs. Fatigue was measured using objective, laboratory-based instruments.
Characteristics of Officers
Total Officers = 275
- 128 from Arlington (Texas) Police Department
- 147 from Detroit (Michigan) Police Department
- 59% white
- 32% Black
- 7% Hispanic
- 2% Asian
- 48% 18-34
- 38% 35-44
- 12% 45-54
- 2% 55+
- 46% married
- 44% single
- 10 % unknown
- 77% male
- 23 % female
Years of Service
- 44% 2-5 years
- 36% 6-9 years
- 19% 10+ years
About This Article
The research described in this article was funded by NIJ award 2005-FS-BX-0057, awarded to the Police Foundation. This article is based on the grantee report The Shift Length Experiment: What We Know About 8-, 10-, and 12-Hour Shifts in Policing by Amenodola, KL., D. Weisburd, E. Hamilton, G. Jones and M. Slipka.