Shift work and overtime across a career in law enforcement: a 15-year study.

PURPOSE ­: To characterize changes in work hours across a career in law enforcement. DESIGN/METHODOLOGY/APPROACH ­: N = 113 police officers enrolled in the BCOPS cohort were studied. The police officers started their careers in law enforcement between 1994 and 2001 at a mid-sized, unionized police department in northwestern New York and continued to work at this police department for at least 15 years. Day-by-day work history records were obtained from the payroll department. Work hours, leave hours and other pay types were summarized for each calendar year across their first 15 years of employment. Linear mixed-effects models with a random intercept over subject were used to determine if there were significant changes in pay types over time. FINDINGS ­: A total of 1,617 individual-years of data were analyzed. As the police officers gained seniority at the department, they worked fewer hours and fewer night shifts. Total paid hours did not significantly change due to seniority-based increases in vacation time. Night shift work was increasingly in the form of overtime as officers gained seniority. Overtime was more prevalent at the beginning of a career and after a promotion from police officer to detective. ORIGINALITY/VALUE ­: Shiftwork and long work hours have negative effects on sleep and increase the likelihood of on-duty fatigue and performance impairment. The results suggest that there are different points within a career in law enforcement where issues surrounding shiftwork and long work hours may be more prevalent. This has important implications for predicting fatigue, developing effective countermeasures and measuring fatigue-related costs.

Generalizability of a biomathematical model of fatigue's sleep predictions.

Introduction: Biomathematical models of fatigue (BMMF) predict fatigue during a work-rest schedule on the basis of sleep-wake histories. In the absence of actual sleep-wake histories, sleep-wake histories are predicted directly from work-rest schedules. The predicted sleep-wake histories are then used to predict fatigue. It remains to be determined whether workers organize their sleep similarly across operations and thus whether sleep predictions generalize.Methods: Officers (n = 173) enrolled in the Buffalo Cardio-Metabolic Occupational Police Stress study were studied. Officers' sleep-wake behaviors were measured using wrist-actigraphy and predicted using a BMMF (FAID Quantum) parameterized in aviation and rail. Sleepiness (i.e. Karolinska Sleepiness Scale (KSS) ratings) was predicted using actual and predicted sleep-wake data. Data were analyzed using sensitivity analyses.Results: During officers' 16.0 ± 1.9 days of study participation, they worked 8.6 ± 3.1 shifts and primarily worked day shifts and afternoon shifts. Across shifts, 7.0 h ± 1.9 h of actual sleep were obtained in the prior 24 h and associated peak KSS ratings were 5.7 ± 1.3. Across shifts, 7.2 h ± 1.1 h of sleep were predicted in the prior 24 h and associated peak KSS ratings were 5.5 ± 1.2. The minute-by-minute predicted and actual sleep-wake data demonstrated high sensitivity (80.4%). However, sleep was observed at all hours-of-the-day, but sleep was rarely predicted during the daytime hours.Discussion: The sleep-wake behaviors predicted by a BMMF parameterized in aviation and rail demonstrated high sensitivity with police officers' actual sleep-wake behaviors. Additional night shift data are needed to conclude whether BMMF sleep predictions generalize across operations.

Fatigue and short-term unplanned absences among police officers.

PURPOSE ­: The purpose of this paper is to assess whether shift work, sleep loss and fatigue are related to short-term unplanned absences in policing. DESIGN/METHODOLOGY/APPROACH ­: N = 367 police officers from the Buffalo Police Department were studied. Day-by-day work and sick leave data were obtained from the payroll. Absenteeism was defined as taking a single sick day on a regularly scheduled workday. Biomathematical models of fatigue (BMMF) predicted officers' sleep-wake behaviors and on-duty fatigue and sleepiness. Prior sleep, fatigue and sleepiness were tested as predictors of absenteeism during the next shift. FINDINGS ­: A total of 513,666 shifts and 4,868 cases of absenteeism were studied. The odds of absenteeism increased as on-duty fatigue and sleepiness increased and prior sleep decreased. This was particularly evident for swing shift officers and night shift officers who were predicted by BMMF to obtain less sleep and have greater fatigue and sleepiness than day shift officers. The odds of absenteeism were higher for female officers than male officers; this finding was not due to a differential response to sleep loss, fatigue or sleepiness. PRACTICAL IMPLICATIONS ­: Absenteeism may represent a self-management strategy for fatigue or compensatory behavior to reduced sleep opportunity. Long and irregular work hours that reduce sleep opportunity may be administratively controllable culprits of absenteeism. ORIGINALITY/VALUE ­: Police fatigue has consequences for police officers, departments and communities. BMMF provide a potential tool for predicting and mitigating police fatigue. BMMF were used to investigate the effects of sleep and fatigue on absenteeism.

U.S. police rosters: Fatigue and public complaints.

STUDY OBJECTIVES: Recent experimental research indicates a substantial impact of shift work related fatigue on police officers' encounters with the public. In recent years, biomathematical models of fatigue have provided a new way to identify potential relationships between working time arrangements and job performance. This study focused on public complaints against police officers and determined whether the odds of a public complaint were associated with work schedules and/or a biomathematical model's predictions of fatigue and sleepiness. METHODS: N = 144 police officers from two municipal police departments in the United States reported shift start times, shift hours, court hours, and public complaints each duty day during study participation. A biomathematical model of fatigue (FAID Quantum) predicted sleep duration and sleep timing and inferred fatigue and sleepiness for 15 744 shifts. Fatigue, sleepiness, 24 hr sleep estimates, and work schedule were tested as predictors of public complaints. RESULTS: Greater fatigue, greater sleepiness, and less sleep in the 24 hr prior to a shift increased the odds of a public complaint (F ≥ 9.14, p < 0.01). Working back-to-back night shifts increased the odds of a public complaint (OR = 4.27, p < 0.01), particularly when off-duty court hours were worked between the night shifts (OR = 4.73, p < 0.01). CONCLUSIONS: On-duty fatigue and sleepiness, sleep obtained prior to a shift, and working night shifts were strongly associated with public complaints. Off-duty court appearances reduced sleep between night shifts and further increased the odds of a public complaint. The results suggest that off-duty court hours should be limited between night shifts and duty schedules should be considered when scheduling court appearances.

Identifying psychophysiological indices of expert vs. novice performance in deadly force judgment and decision making.

OBJECTIVE: To demonstrate that psychophysiology may have applications for objective assessment of expertise development in deadly force judgment and decision making (DFJDM). BACKGROUND: Modern training techniques focus on improving decision-making skills with participative assessment between trainees and subject matter experts primarily through subjective observation. OBJECTIVE metrics need to be developed. The current proof of concept study explored the potential for psychophysiological metrics in deadly force judgment contexts. METHOD: Twenty-four participants (novice, expert) were recruited. All wore a wireless Electroencephalography (EEG) device to collect psychophysiological data during high-fidelity simulated deadly force judgment and decision-making simulations using a modified Glock firearm. Participants were exposed to 27 video scenarios, one-third of which would have justified use of deadly force. Pass/fail was determined by whether the participant used deadly force appropriately. RESULTS: Experts had a significantly higher pass rate compared to novices (p < 0.05). Multiple metrics were shown to distinguish novices from experts. Hierarchical regression analyses indicate that psychophysiological variables are able to explain 72% of the variability in expert performance, but only 37% in novices. Discriminant function analysis (DFA) using psychophysiological metrics was able to discern between experts and novices with 72.6% accuracy. CONCLUSION: While limited due to small sample size, the results suggest that psychophysiology may be developed for use as an objective measure of expertise in DFDJM. Specifically, discriminant function measures may have the potential to objectively identify expert skill acquisition. APPLICATION: Psychophysiological metrics may create a performance model with the potential to optimize simulator-based DFJDM training. These performance models could be used for trainee feedback, and/or by the instructor to assess performance objectively.

The safety and health improvement: enhancing law enforcement departments study: feasibility and findings.

This randomized prospective trial aimed to assess the feasibility and efficacy of a team-based worksite health and safety intervention for law enforcement personnel. Four-hundred and eight subjects were enrolled and half were randomized to meet for weekly, peer-led sessions delivered from a scripted team-based health and safety curriculum. Curriculum addressed: exercise, nutrition, stress, sleep, body weight, injury, and other unhealthy lifestyle behaviors such as smoking and heavy alcohol use. Health and safety questionnaires administered before and after the intervention found significant improvements for increased fruit and vegetable consumption, overall healthy eating, increased sleep quantity and sleep quality, and reduced personal stress.

Shift work and long-term injury among police officers.

OBJECTIVE: Our previous work has suggested that the incidence of any occurrence of injury leave among police officers is higher on night shifts. In this study, we extended our inquiry to determine whether the incidence of long-term injury leave varies across shifts. METHODS: Police officers (N=419) from an urban department were included in the analysis. Daily payroll work history data from 1994-2010 was collected. Injury leave duration was examined ranging from ≥1-≥90 days. Poisson regression models were used to compute incidence rates (IR) and incidence rate ratios (IRR) of long-term injury. RESULTS: Cumulative incidence of injury for different durations of leave defined as ≥1, ≥5, ≥10, ≥15, ≥30, and ≥90 days were 61.3%, 45.4%, 39.9%, 33.9%, 26.5%, and 9.6% respectively. Age-and gender adjusted IRR of long-term injury (≥90 days) for night versus day shifts was IRR 3.12, 95% confidence interval (95% CI) 1.35-7.21 and IRR 2.21, 95% CI 1.04-4.68, for night versus afternoon shifts. Among all durations examined, the largest IRR was for injury ≥90 days, night versus day shifts (IRR 3.12, 95% CI 1.35-7.21). CONCLUSIONS: Night shift work was significantly associated with long-term injury among police officers after adjustment for age and gender. Although type of injury was not available, it is possible that variation in injury type across shifts might account for some of this association.

Efficient driver drowsiness detection at moderate levels of drowsiness.

Previous research on driver drowsiness detection has focused primarily on lane deviation metrics and high levels of fatigue. The present research sought to develop a method for detecting driver drowsiness at more moderate levels of fatigue, well before accident risk is imminent. Eighty-seven different driver drowsiness detection metrics proposed in the literature were evaluated in two simulated shift work studies with high-fidelity simulator driving in a controlled laboratory environment. Twenty-nine participants were subjected to a night shift condition, which resulted in moderate levels of fatigue; 12 participants were in a day shift condition, which served as control. Ten simulated work days in the study design each included four 30-min driving sessions, during which participants drove a standardized scenario of rural highways. Ten straight and uneventful road segments in each driving session were designated to extract the 87 different driving metrics being evaluated. The dimensionality of the overall data set across all participants, all driving sessions and all road segments was reduced with principal component analysis, which revealed that there were two dominant dimensions: measures of steering wheel variability and measures of lateral lane position variability. The latter correlated most with an independent measure of fatigue, namely performance on a psychomotor vigilance test administered prior to each drive. We replicated our findings across eight curved road segments used for validation in each driving session. Furthermore, we showed that lateral lane position variability could be derived from measured changes in steering wheel angle through a transfer function, reflecting how steering wheel movements change vehicle heading in accordance with the forces acting on the vehicle and the road. This is important given that traditional video-based lane tracking technology is prone to data loss when lane markers are missing, when weather conditions are bad, or in darkness. Our research findings indicated that steering wheel variability provides a basis for developing a cost-effective and easy-to-install alternative technology for in-vehicle driver drowsiness detection at moderate levels of fatigue.

A combined field and laboratory design for assessing the impact of night shift work on police officer operational performance.

OBJECTIVES: This study assessed the utility of a combined field and laboratory research design for measuring the impact of consecutive night shift work on the sleepiness, vigilance, and driving performance of police patrol officers. DESIGN: For police patrol officers working their normal night shift duty cycles, simulated driving performance and psychomotor vigilance were measured in a laboratory on two separate occasions: in the morning after the last of five consecutive 10.7-h night shifts, and at the same time in the morning after three consecutive days off duty. Order of participation in conditions was randomized among subjects. SETTING: Subjects experienced manipulation of sleep schedules due to working night shifts in a real operational environment, but performance testing was conducted under controlled laboratory conditions. PARTICIPANTS: N = 29 active-duty police patrol officers (27 male, 2 female; age 37.1 ± 6.3 years) working night shift schedules participated in this study. RESULTS: Simulated driving performance, psychomotor vigilance, and subjective sleepiness were significantly degraded following 5 consecutive night shifts as compared to 3 consecutive days off duty, indicating that active-duty police officers are susceptible to performance degradation as a consequence of working nights. CONCLUSIONS: This combined field and laboratory research design succeeded in bridging the gap between the realism of the operational environment and the control of laboratory performance testing, demonstrating that this is a useful approach for addressing the relationship between shift work induced fatigue and critical operational task performance.

Neurotechnology to accelerate learning: during marksmanship training.

This article explores the psychophysiological metrics during expert and novice performances in marksmanship, combat deadly force judgment and decision making (DFJDM), and interactions of teams. Electroencephalography (EEG) and electrocardiography (ECG) are used to characterize the psychophysiological profiles within all categories. Closed-loop biofeedback was administered to accelerate learning during marksmanship training in which the results show a difference in groups that received feedback compared with the control. During known distance marksmanship and DFJDM scenarios, experts show superior ability to control physiology to meet the demands of the task. Expertise in teaming scenarios is characterized by higher levels of cohesiveness than those seen in novices.

Shift work and the incidence of injury among police officers.

BACKGROUND: Police officers may be injury prone due to fatigue, erratic work hours, and insufficient sleep. This study explored injury incidence among police officers across shifts. METHODS: Day-to-day shift data from computerized payroll records (1994-2010) were available from a mid-sized urban police department (n = 430). Sleep duration, shift activity level, returning to work after days off, and injury incidence over time were also examined. RESULTS: Age-adjusted incidence rate ratio (IRR) for injury on the midnight shift was 72% larger than the day shift (IRR = 1.72; 95% CI = 1.26-2.36) and 66% larger than the afternoon shift (IRR = 1.66; 95% CI = 1.23-2.25). Injury incidence for the first day back on the midnight shift was 69% larger than day shift (IRR = 1.69; 95% CI = 1.23-2.32) and 54% larger than the afternoon shift (IRR = 1.54; 95% CI = 1.36-1.76). High activity level combined with midnight shift work put officers at increased injury risk (IRR = 2.31; P = 0.0003). Probability of remaining free of injury was significantly higher for day shift than midnight shift (P < 0.0001). CONCLUSIONS: Higher injury risk was associated with night shift work in police officers. Night shift combined with high work activity was strongly associated with injury risk. There was a significantly higher probability of not being injured on day compared to midnight or afternoon shifts.

The efficacy of a restart break for recycling with optimal performance depends critically on circadian timing.

OBJECTIVES: Under simulated shift-work conditions, we investigated the efficacy of a restart break for maintaining neurobehavioral functioning across consecutive duty cycles, as a function of the circadian timing of the duty periods. DESIGN: As part of a 14-day experiment, subjects underwent two cycles of five simulated daytime or nighttime duty days, separated by a 34-hour restart break. Cognitive functioning and high-fidelity driving simulator performance were tested 4 times per day during the two duty cycles. Lapses on a psychomotor vigilance test (PVT) served as the primary outcome variable. Selected sleep periods were recorded polysomnographically. SETTING: The experiment was conducted under standardized, controlled laboratory conditions with continuous monitoring. PARTICIPANTS: Twenty-seven healthy adults (13 men, 14 women; aged 22-39 years) participated in the study. INTERVENTIONS: Subjects were randomly assigned to a nighttime duty (experimental) condition or a daytime duty (control) condition. The efficacy of the 34-hour restart break for maintaining neurobehavioral functioning from the pre-restart duty cycle to the post-restart duty cycle was compared between these two conditions. RESULTS: Relative to the daytime duty condition, the nighttime duty condition was associated with reduced amounts of sleep, whereas sleep latencies were shortened and slow-wave sleep appeared to be conserved. Neurobehavioral performance measures ranging from lapses of attention on the PVT to calculated fuel consumption on the driving simulators remained optimal across time of day in the daytime duty schedule, but degraded across time of night in the nighttime duty schedule. The 34-hour restart break was efficacious for maintaining PVT performance and other objective neurobehavioral functioning profiles from one duty cycle to the next in the daytime duty condition, but not in the nighttime duty condition. Subjective sleepiness did not reliably track objective neurobehavioral deficits. CONCLUSIONS: The 34-hour restart break was adequate for maintaining performance in the case of optimal circadian placement of sleep and duty periods (control condition) but was inadequate (and perhaps even detrimental) for maintaining performance in a simulated nighttime duty schedule (experimental condition). Current US transportation hours-of-service regulations mandate time off duty but do not consider the circadian aspects of shift scheduling. Reinforcing a recent trend of applying sleep science to inform policymaking for duty and rest times, our findings indicate that restart provisions in hours-of-service regulations could be improved by taking the circadian timing of the duty schedules into account.

Association of perceived stress with sleep duration and sleep quality in police officers.

The objective was to investigate associations ofperceived stress with sleep duration and quality among 430 police officers. Perceived stress was assessed using the perceived stress scale. Sleep duration and quality were assessed using the Pittsburg sleep quality index questionnaire. Mean hours of sleep were determined across quartiles of perceived stress using ANOVA/ANCOVA. Logistic regression was used to obtain odds ratios and 95% confidence intervals for poor sleep quality across perceived stress quartiles. Mean age was 42.1 years. Perceived stress was inversely associated with sleep duration among certain groups: men (p = 0.004), higher-ranked officers (p = 0.002), those with higher depressive symptoms (p 0.097), no military experience (p = 0.006), and higher workload (p = 0.003). Gender, police rank, depressive symptoms, and workload each significantly modified the association between stress and sleep duration. Prevalence of poor sleep quality increased with higher levels of perceived stress; the trend was significant among men only (p < 0.0001), and gender significantly modified this association (interaction p = 0.015). Compared to those in the first quartile of perceived stress, women in the fourth quartile were almost four times and men almost six times more likely to have poor sleep quality. Perceived stress was inversely associated with sleep duration and positively associated with poor sleep quality.

Atypical work hours and metabolic syndrome among police officers.

This study examined whether atypical work hours are associated with metabolic syndrome among a random sample of 98 police officers. Shift work and overtime data from daily payroll records and reported sleep duration were obtained. Metabolic syndrome was defined as elevated waist circumference and triglycerides, low HDL cholesterol, hypertension, and glucose intolerance. Multivariate analysis of variance and analysis of covariance models were used for analyses. Officers working midnight shifts were on average younger and had a slightly higher mean number of metabolic syndrome components. Stratification on sleep duration and overtime revealed significant associations between midnight shifts and the mean number of metabolic syndrome components among officers with less sleep (p = .013) and more overtime (p = .007). Results suggest shorter sleep duration and more overtime combined with midnight shift work may be important contributors to the metabolic syndrome.

Shift-work and suicide ideation among police officers.

BACKGROUND: This cross-sectional study assessed the association of shift work with suicide ideation among police officers. METHODS: Shift work was based on daily payroll records over 5 years (41 women, 70 men). Standardized psychological measures were employed. ANOVA and Poisson regression were used to evaluate associations. RESULTS: Among policewomen with increased depressive symptoms, prevalence of suicide ideation increased by 116% for every 10-unit increase in percentage of hours worked on day shift (prevalence ratio (PR) = 2.16; 95% confidence interval (CI) = 1.22-3.71). Among policemen with higher (but not lower) posttraumatic stress disorder (PTSD) symptoms, prevalence of suicide ideation increased by 13% with every 10-unit increase in the percentage of hours worked on afternoon shift (PR = 1.13; 95% CI = 1.00-1.22). CONCLUSION: Prevalence of suicide ideation significantly increased among policewomen with higher depressive symptoms and increasing day shift hours, and among policemen with higher PTSD symptoms with increasing afternoon shift hours.

Long working hours, safety, and health: toward a National Research Agenda.

BACKGROUND: A significant and growing number of people work long hours. Research examining impacts is limited, but raises concerns about risks to the worker, the family, the employer, and the community. The purpose of this report, which is authored by the National Occupational Research Agenda (NORA) Long Work Hours Team, is to motivate and guide future research by proposing a framework for studying long work hours and discussing research gaps. METHODS: The NORA Long Work Hours Team examined research reports and literature reviews, and gathered input from a conference on long work hours organized by the Team and faculty from University of Maryland. RESULTS AND CONCLUSION: A framework is proposed for long work hours, including determinants, outcomes, and moderating factors of long work hours, suggesting that studies need to include more clear and complete descriptions of work schedules, worker characteristics, and the work environment, and need to consider a wider range of possible health, safety, social and economic outcomes for workers, families, employers, and the community. Additional studies are needed on vulnerable employee groups and those critical to public safety. More studies are also needed to develop interventions and test their effectiveness.