Top 10 Shift Work Myths

Myth #1 – Overtime within your workforce is evenly distributed

Best practices suggest that when overtime is equally distributed across a workforce, up to approximately 12% overtime is an acceptable rate. However, overtime rates vary across industries, companies and employees.

Research indicates that in many industries, 20% of employees work 60% or more of the overtime (Figure 4).1

Figure 4. Actual distribution of overtime at an extended hours facility.1Overtime distribution

Since accidents and safety problems can be caused by one fatigued employee, the risk of an accident occurring can rise as the distribution of overtime becomes increasingly skewed.

The imbalance exposes the pool of high overtime employees to extra health risks, and exposes the company to increased absenteeism costs, health care costs, safety issues, and legal liability.

Myth #2 – Employee productivity increases linearly

Studies and reports suggest that productivity can suffer with increased overtime hours.

Data from 18 manufacturing industries in the U.S. shows that for most of these industries, productivity (measured as output per hour) declines when overtime is used.2

On average, a 10% increase in overtime results in a 2.4% decrease in productivity (more output is achieved, but the number of hours worked increases as well—not as much output per hour is realized).

This performance decline is confirmed by the work of J. Nevison of Oak Associates. In his white paper, Nevison brings together scientific, business, and government data to demonstrate that little productive work takes place over and above 50 hours per week (Figure 2)3. Two other studies, also examined in the white paper, show that productive hours drop by an additional 10 hours when the number of consecutive long workweeks increases from four to 12, highlighting the cumulative effects that overtime can have on productivity.

Figure 2. Productive vs. actual work hours, from a collection of four studies4
overtime and productivity

Myth #3 – Adequate staffing means having enough employees to cover permanent positions

Often overlooked are the real drivers of overtime in 24/7 operations. In any given week, employees may not be available to fill their scheduled shifts because of multiple reasons including:

  • Vacation days
  • Floating holidays
  • Sickness related absenteeism
  • Non-sickness related absenteeism/personal days
  • Injury-related absenteeism
  • Training
  • Special work assignments (committees, team building, projects, etc.)
  • Jury duty, bereavement, FMLA, etc.
  • Turnover/delays in filling position with adequately trained employees

Many 24/7 operations do not realistically estimate or measure the full impact of these factors and hence run their shifts with fewer staff than needed, effectively increasing the relief coverage requirement (i.e. overtime) and impacting the time on duty and off duty of their personnel.

Furthermore, many companies do not monitor and analyze their historical payroll and human resources data so that they are unable to make even simple forecasts about scheduled and unscheduled absenteeism. Without this data, they are unable to accurately define seasonal, weekly and daily fluctuations in coverage demand.

Based on CIRCADIAN's 2014 Shiftwork Practices data, we found that the "leaner" operations (i.e. reduced staffing levels) reported higher absenteeism rates (Figure 1).

Interestingly, over 50% of all unscheduled absences are due to either: personal needs, stress, or an entitlement mentality (i.e. “I’ve earned it”).5

Figure 1. Staffing Levels & Absenteeism Rate 5absenteeism and staffing levels

Myth #4 – Operational decisions on shift scheduling are best if mandated by management.

Management-mandated work schedules often prevent an operation from reaching its full potential in terms of operational costs, productivity, efficiency, and safety.

Employee participation is just as important in the process of designing and implementing the new work schedule as the characteristics of the new work schedule itself.6-9

Surveys suggest that management-mandated work schedules can lead to:10

  • Increased absenteeism
  • Excessive overtime costs
  • Increased health problems and fatigue
  • Decreased morale
  • Increased turnover costs
  • Recruitment problems

Studies comparing methods of shift schedule selection have found that employee involvement in schedule redesign increases the benefits of schedule redesign considerably, as compared to management-mandated schedule changes. These benefits include:11-18

  • Increased worker satisfaction with schedule design
  • Decreased unscheduled absences from illness
  • Improved physical and psychological vigor
  • Decreased turnover and number of vacant positions
  • Increased organizational commitment
  • Improved employee and management relations

Myth #5 – If a shift schedule works well at our other plant, it will work for us here.

This is a common misconception in companies with multiple facility locations. A shift schedule that’s effective and well-liked at one facility can cause disagreements and tension among workers at a seemingly identical facility.

Shift schedules need to be based on the social, operational and physiological needs of the workforce and managers at each specific company site. Some factors to consider include:

  • Geographic location
  • The lifestyles of workers
  • Cultural differences
  • Worker demographics

These factors can greatly impact the popularity of different shift schedules among workers. For example, avoiding rush hour traffic is often important to workers in large cities, whereas workers in rural areas might prefer longer spans of days off.

Best shift scheduling practices suggest choosing a schedule with features that support the priorities of workers at each individual facility.

Pleasing everyone may be impossible, but having the majority of workers in favor of a new shift schedule will greatly increase the likelihood of a successful schedule change.

Myth #6 – Given the choice, workers always select the best schedule for them and the worst for the company.

Much conflict between management and shiftworkers is the result of misunderstanding and poor communication.

Management often feels that it is doing its part by “telling,” rather than both telling and listening to the needs of workers. Workers may feel that they’re providing valuable insight, but management only hears the complaints. As a result, management may feel that workers only care about themselves and making money.

While the occasional worker may try to game the system, most workers are truly concerned with the well-being of the company. After all, workers realize that any problem that the company faces will ultimately affect them. In light of this, most workers will choose a schedule that will satisfy the company while still fulfilling their individual needs.

The best way to ensure that workers understand the reasons for making any scheduling changes is by keeping them informed. This can be accomplished through company-wide meetings or events, as well as through regular emails or letters about the general state of the company.

Myth #7 – Falling asleep on the job is a matter of willpower

While curling up with a pillow and blanket at work is clearly deliberate, many fatigued individuals unknowingly experience microsleeps while working. A microsleep is a brief sleep episode that lasts up to 30 seconds, during which a person temporarily loses consciousness and external stimuli aren’t perceived.19

Individuals who experience microsleeps are often unaware that they briefly lost consciousness and will frequently deny that they fell asleep.20 When an individual arouses from a microsleep episode, it may feel like a brief lapse in attention or mind wandering.

Research suggests that even individual neurons can experience microsleeps, which means that your parts of the brain may be “offline” even if you’re seemingly awake.21

Microsleeps are most commonly associated with sleep deprivation and driving; however, microsleeps can also occur in the absence of sleep deprivation when completing monotonous, repetitive tasks.

Myth #8 – Napping during work is a lazy and unacceptable behavior

Before you write off napping as a leisurely activity that should be banned at work, you might want to consider the ways in which napping at your workplace can improve the alertness and productivity of workers.

Ten minute power naps provide immediate benefits upon awakening and boosts in performance that can last up to 4 hours!

Ten minute naps have been shown to: decrease fatigue, increase vigor, improve performance, improve communication, decrease blood pressure, improve reaction time, improve subject well-being, and increase alertness.

Longer naps that last 90 minutes (or longer) still offer many restorative benefits; however, they are not as efficient as power naps. Longer naps allow for memory consolidation and therefore have been shown to improve memory. Extended napping is frequently associated with profound sleep inertia, which can be crippling to productivity. In order to avoid the sleep inertia of long naps, it's advised to sleep a full 90 min sleep cycle in order to wake up at the lightest sleep stage.

Myth # 9 – Hours of service requirements are sufficient for mitigating employee fatigue

Most fatigue regulations start and end with hours of service policies. While this is a good starting place, it fails to address all of the factors that contribute to fatigue. To ensure the alertness of workers, a comprehensive fatigue risk management system (FRMS) needs to be in place.

CIRCADIAN® 5 Defenses FRMS Design

Fatigue risk management system

A fatigue risk management system (FRMS) is a data-driven, risk-informed, safety performance-based program that reduces the risk of fatigue-related incidents in 24/7 operations. An FRMS will continually monitor and reduce fatigue risk.

Workforces that have implemented fatigue risk management systems experience fewer problems with absenteeism, turnover and excessive overtime. Employees in these workforces have greater morale, less stress, and are more productive workers.

Myth #10 – There’s very little financial ROI with fatigue risk management

To some, fatigue might seem like a minor concern, yet it costs companies millions of dollars each year in excess costs, accidents and errors.

Fatigued workers cost employers $136.4 billion annually in health-related lost productive time (absenteeism and presenteeism), almost 4x more than their non-fatigued counterparts.22

Fatigued workers exhibit up to 4x the worker’s compensation costs as compared to non-fatigued workers (Figure 3).24 A recent meta-analysis of 27 observational studies found that sleep problems increase the risk of workplace injuries by 62 percent.23

Figure 3. Fatigue Levels & Worker’s Compensation24

fatigue and worker compensation Addressing and mitigating fatigue within an operation can significantly decrease excess costs related to: absenteeism, turnover, accidents, and healthcare.

fatigue risk management system savings


Debunk Other Shift Work Myths

Explore the variety of CIRCADIAN white papers that cover an assortment of 24/7 workforce topics including:

  • Shift Scheduling
  • Staffing Levels
  • Fatigue Risk Management Systems
  • Shiftwork Lifestyle Training
  • And much more!

white papers



  1. CIRCADIAN databases
  2. Shepard E, Clifton T. Are Long Hours Reducing Productivity in Manufacturing. International Journal of Manpower 2000; 7.
  3. Nevison, J. Overtime Hours: The Rule of Fifty
  4. Permission from Nevison, Oak Associates.
  5. CIRCADIAN. 2014 Shiftwork Practices.
  6. Hauburger. Implementation of self-scheduling in the poison center. Vet. Hum. Toxicol. 39(3),175-7. 1997.
  7. Knauth P.The design of shift systems. Ergonomics 36(1-3),15-28. 1993.
  8. Knauth P. Changing schedules: shiftwork. Chronobiol. Int. 14(2),159-71. 1997.
  9. Kogi K, Di Martino VG. Trends in participatory process of changing shiftwork arrangements. Work & Stress 9 (2/3), 298-304. 1995.
  10. Circadian Technologies, Shiftwork Practices Survey 2002.
  11. Ala-Mursula et al. Employee control over working times: associations with subjective health and sickness absences. J. Epidemiol. Community Health 56(4),272-8. 2002.
  12. Beltzhoover M. Self-scheduling: an innovative approach. Nurs. Manage. 25(4),81-2. 1994.
  13. Bradley, Martin. Continuous personnel scheduling algorithms: a literature review. J. Soc. Health Syst. 2(2),8-23. 1991.
  14. Holtom et al. The relationship between work status congruence and work-related attitudes and behaviors. J. Appl. Psychol. 87(5),903-15. 2002.
  15. Moore-Ede M. The Twenty-Four Hour Society: Understanding Human Limits in a World that Never Sleeps. 1994.
  16. Smith PA et al. Change from slowly rotating 8-hour shifts to rapidly rotating 8-hour and 12-hour shifts using participative shift roster design. Scand. J. Work Environ. Health. 24(S3), 55-61. 1998.
  17. Teahan. Implementation of a self-scheduling system: a solution to more than just schedules! J. Nurs. Manag. 6(6),361- 81. 998. Erratum in: J. Nurs. Manag. 7(1),65. 1999.
  18. Sakai K et al. Educational and intervention strategies for improving a shift system: an experience in a disabled persons' facility. Ergonomics 36(1-3),219-25. 1993.
  19. International Classification of Sleep Disorders Diagnostic and Coding Manual,, page 343.
  20. Higgins, Laura; Fette Bernie (in press). "Drowsy Driving" (PDF). Retrieved 2013-06-12.
  21. Vyazovskiy, V. V., Olcese, U., Hanlon, E. C., Nir, Y., Cirelli, C., & Tononi, G. (2011). Local sleep in awake rats. Nature, 472(7344), 443-447.
  22. Ricci, J. A., Chee, E., Lorandeau, A. L., & Berger, J. (2007). Fatigue in the US workforce: prevalence and implications for lost productive work time. Journal of Occupational and Environmental Medicine, 49(1), 1-10.
  23. Katrin Uehli, Amar J. Mehta, David Miedinger, Kerstin Hug, Christian Schindler, Edith Holsboer-Trachsler, Jörg D. Leuppi, et al. (2014). Sleep problems and work injuries: A systematic review and meta-analysis. Sleep Medicine Reviews. doi:10.1016/j.smrv.2013.01.004
  24. Aguirre, A. Shiftwork Practices Survey, 2005.

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