Custom-Designed Employee Work Schedules
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What time do most day shift workers want to start work? Surprisingly, few want to start at 8:00 a.m. or later. Most want to start before 7:00 a.m., as shown in the diagram below.
Why do so many people want to start work early? Workers tell us there are two reasons.
First, they want to get home earlier. It may be possible to arrive at home around the same time their children get out of school. There is more time in the evening to run personal errands or spend time with the family and friends. And, of course, there are more hours of daylight available for recreation, house repairs, or anything else best done while the sun is out.
Shiftworker Preferred Start Times
Median for 8-hour shifts = 6:30 a.m.
Median for 12-hour shifts = 6:00 a.m.
The second reason is they want to avoid traffic congestion during the commute to and from work. Nobody enjoys sitting in stalled traffic or poking along at a fraction of the posted speed limit. By starting work a little earlier, workers can avoid the rush hour and spend less time on the road. More than one shift worker has told us that by starting 15 minutes earlier they saved up to 45 minutes on their commute.
In addition, preferred work start times are heavily influenced by what people are familiar with. The graph below shows the preferred start times from two companies whose actual start times are significantly different. In both cases, the employees would like to have earlier start times. But the average preferences at the two plants are more than an hour apart. Clearly, the preferred start times are tempered by what the workers are used to. Once a start time is changed, preferences will gradually evolve, making acceptance of any change in start times a long-term process.
Preferred Start Times at Two Different Companies
A Company A
Company B
Current start time
6:30 a.m.
8:00 a.m.
Preferred start time (average)
6:27 a.m.
7:37 a.m.
What most people don't realize, however, is that early start times often result in less sleep. Why? Because most people won't go to bed earlier to adjust for an early work start time. They would rather sacrifice their sleep than their normal evening activities.
Here is an example from a major auto parts manufacturing plant. The plant operates on two different schedules that are an hour apart. Three-quarters of the workers on day shift start work at 6:30 a.m. The rest start an hour later at 7:30 a.m.
When surveyed, employees with the later starting time said they got an average of 34 minutes more sleep on the days they worked than the employees with the early start time did. The later start time simply allowed them to sleep longer. On their days off, both groups got about the same amount of sleep.
Asked how often they had problems with safety or performance due to sleepiness, the group with the later starting time reported they had frequent problems 31% less often than the employees on the earlier day shift. In addition, the “later starters” accounted for only 14% of the accidents over a one-year period, despite representing 24% of the total workers.
The later start times had mixed results with the afternoon and night shifts at the plant. As seen in the table below, the second shift with late start times got a little more sleep and the third shift with late start times got a little less sleep. The day shift was the only shift that experienced a significant change.
Shift
Average Hours of Sleep
Difference
Early Start
Late Start
Day shift
5.78 hours/day
6.34 hours/day
+34 minutes
Afternoon shift
6.46 hours/day
6.59 hours/day
+8 minutes
Night shift
5.98 hours/day
5.80 hours/day
-11 minutes
This is not an isolated case. The National Institute for Occupational Safety and Health (NIOSH) and the Finnish Institute of Occupational Health found that a one-hour delay in morning shift start times at a steel mill increased worker sleep and improved waking alertness during the shift. They believe that sleep is often truncated when workers have early start times. The reason? Social limitations on retiring early in the evening. They also found that the evening and night shifts were affected negatively by starting work later, however, the results were not consistent.
The evidence seems to be consistent in supporting the conclusion that later start times increase the hours of sleep, at least for people working the morning shift. The question is whether the workers would choose later start times when given the choice. Does the advantage of extra sleep outweigh the disadvantages of longer commute times and less free time after work? And what about people working the other shifts? They didn't gain the same benefits, so why should they support a change?
In the NIOSH/Finnish study, the workers were allowed to vote on changing the schedule after a four-month trial of later start times. 75% of the workers voted against the later start times. The workers explained that this choice was unpopular because it interfered with social and other personal activities. How do you think your workforce would vote? Don't you think it's worth giving them the opportunity to decide? Before you do, make sure they are familiar with the studies described in this article.
Sources
1. Roger R Rosa, Mikko Harma, Katriina Pulli, Mirjam Mulder, Ove Nasman, “Rescheduling a three shift system at a steel rolling mill: effects of a one hour delay of shift starting times on sleep and alertness in younger and older workers,” Occupational andEnvironmental Medicine, Oct. 1996, Volume 53, No. 10, pp.677-685.
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This is the third in a series of posts regarding fatigue in the workplace. The first post addressed educating employees about the need for 8-hours sleep and the impact of sleep deprivation. The second post addressed early day shift start times and how they reduce the amount of sleep people get. This post will address the impact of shift length on sleep and fatigue.
Intuitively, you would think that the longer the work day, the less sleep you would get. To a certain extent, this is right. We have found that people working a 12-hour shift get about 10 minutes less sleep per night than people working an 8-hour shift. But that's not a complete picture since it is only looking at the days of work.
People on longer shifts get more days off. Workers on 12-hour shifts will get 87 more days off each year than those on 8-hour shifts. Since people sleep more on their days off than they do on the days of work, the people on 12s actually will average more sleep than those on the 8-hour work days. Here's a link to a table showing the details: http://www.shift-schedule-design.com/12-Hour_Shifts. You may have to scroll down a couple of times to find the table.
What do think? Counter-intuitive isn't it?
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In my last 3 posts, I recommended using the following criteria to ensure a comprehensive approach to the schedule selection process: (1) effectiveness, (2) efficiency, (3) sleep, and (4) employee satisfaction. This post will cover the third criterion - sleep.
When a schedule adversely impacts employee sleep, this can lead to health and safety problems. The following schedule elements are known to do this:
1. Excessive hours of work. If the schedule averages more than 42 hours a week, this could be a problem Since additional overtime is often needed to cover absences, 42 hours is probably the most hours the schedule should have. There may be occasional need to increase the hours of work, but as long as it doesn't last more than 4 to 6 weeks, you should be okay. You can read more about this topic here: http://www.shift-schedule-design.com/uploaded/files/Overtime%20Problems.pdf
2. Too many consecutive days of work. For 8-hour schedules, more than 7 consecutive shifts is excessive. For 10-hour shifts, more than 5 consecutive shifts is too many. For 12-hour shifts, more than 4 consecutive shifts is too many. There are a few 12-hour schedules that have an occasional block of 5 shifts in a row, but they tend to offer longer breaks to recover from the sleep loss on the days of work.
3. Rotating shifts. Employees who work fixed shifts tend to get more sleep. Employees assigned to a permanent night shift get about the same amount of sleep as employees on a rotating shift schedule. There are many good reasons for organizations to avoid fixed shifts, but management should be aware of the impact on employee sleep and alertness. To read more about this topic, check this out: http://www.shift-schedule-design.com/Fixed_Shifts.
4. Early start times. If the day shift starts before 7 a.m., employees will get less sleep. I wrote a blog post on this subject several months ago. Here's a link: http://www.shift-schedule-design.com/Blog?m8:post=problems-with-early-morning-start-times.
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This is the 4th post on the subject of "fatigue in the work place."
People get less sleep on the days they work than the days they are off. With each consecutive day of work, they fall farther and farther behind in their sleep, or what is commonly referred to as sleep debt. Sleep debt accumulates and is very subtle. People don't realize they are losing a small bit of cognitive ability every day their sleep debt builds up. With each passing night, they come to work less safe and less productive.
Reducing the number of consecutive days of work, gives employees time off to catch up on their sleep and pay off some of the sleep debt. While the number of days needed to fully recover is uncertain, most researchers believe that at least 2 days off in a row are needed to have a recuperative impact.
The problem with reducing the number of consecutive days of work, of course, is that the number of weekends off can drop dramatically, especially with 8-hour shifts. There is no easy solution to this. The schedules we design never exceed 7 consecutive 8-hour shifts or 4 consecutive 12-hour shifts. Only in special circumstances do we feel that these limits can be exceeded safely.
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This is the second post in a series on the subject of fatigue. In each post, I will focus on steps that management can take to address fatigue.
In the first post, I noted that employees don't think they need more than 7 hours sleep. Managers may want to post articles explaining the impact of sleep debt and the need for more than 7 hours of sleep a day. Just run a Google search for "sleep debt" and copy of few of the articles. If you can find anything by William Dement, he is the subject matter expert. I doubt that doing this will change employee behavior, but it may help to justify any actions management undertakes to address fatigue.
This post draws from a previous post in which I showed how early shift start times reduce the average hours of sleep for day shift workers (http://www.shift-schedule-design.com/Blog?m8:post=problems-with-early-morning-start-times). To summarize, people who start work at 7 a.m. sleep about 20 minutes more per night than those who start a 6 a.m.
Changing shift start times is difficult because people build their lives outside of work around the shift start and end times. When I review employee surveys, they often list the pros and cons of early start times. They say that the best thing about their current schedule is that they get off early, giving them time to do all sorts of things. Then they turn around and say that the worst thing about their schedule is having to get up so early and always feeling tired. How do you resolve this dilemma? It's both the best and worst features of your schedule - at the same time.
The other consideration with shift start times is traffic congestion. Later shift start times may require employees to spend extra time commuting. This takes time away from other activities. For those "other" activities to continue to take place, sleep is often the first thing sacrificed. Although many companies flex their hours to allow commuters to minimize time spent in traffic, this can be challenging for those with shiftwork operations.
Early start times affect more than just shift workers. I've seen articles about the impact of early school start times on student performance. Teenagers have an internal clock that makes it difficult for them to be alert early in the morning, suggesting that learning would improve if schools started at 9 a.m. instead of 8 a.m.
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The American workforce is at war with a subtle enemy. That enemy is so subtle that many deny it even exists. The name of the enemy is fatigue and the cause is sleep deprivation.
Employee surveys show that most people think they only need 7 hours of sleep per night, yet they are actually getting much less than that. People readily exchange sleep for other activities, thinking there is little harm.
The fact is they need 8 hours. The result is a continual build-up of sleep debt as they get less sleep than they need night after night. After two weeks of mild sleep deprivation, cognitive abilities approach those of someone who is legally drunk.
Convincing employees that getting less than 8 hours of sleep is unsafe and unhealthy is not an easy task. Even if they believe that to be true, they still feel the sacrifice is worth the extra time spent with family, friends, hobbies, or simply watching TV.
I'm going to post a few more blogs on some of tactics managers can use to address fatigue in the workplace. If you have any horror stories you'd like to share, please feel free to post a comment.
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This is the 7th an final post in a series on Fatigue in the Workplace. Previous posts on this topic have covered the impact of: (1) education, (2) start times, (3) shift length, (4 consecutive days of work, (5) rotating shifts, and (6) employee preferences. Today's post will address the role of overtime in employee alertness and fatigue.
Let's face it, overtime disrupts people's lives. They have plans that get changed at the last minute. They are forced to work when they had other plans. How do they respond? Forfeiting sleep is one of the most common ways employees try to recover time off lost to overtime.
How much overtime is too much is a difficult question to answer. Most companies feel that an annual average of between 5% and 15% is about right. However, there are a lot of considerations other than alertness that go into finding the perfect amount for any operation. You may wish to read a more complete article on the impact of high overtime (http://www.shift-schedule-design.com/preview/uploaded/files/Overtime%).
Here is a quick summary from the above referenced article. "Our surveys of shiftworkers show that, on average, they get 21% less sleep time on the days they work than the days they are off. When employees work lots of overtime, they don't get time off to recover or catch up on their sleep. This, in turn, can lead to fatigue and reduced alertness. Managers simply cannot ignore the possibility of increased safety and quality incidents under these conditions."
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One of the most popular 12-hour police schedules is the 2-3-2 pattern, also known as the Pitman (or sometimes Pittman) schedule. The reason for its popularity is you only have to work 2 or 3 days in a row and you get every other weekend off as a 3-day weekend. No wonder so many people think it's the best. But you probably didn't know that there are some big downsides to this pattern for the night shift.
Let me explain.
Most people working the night shift tend to stay awake during the daytime on their days off (roughly 75% of the people on 12-hour shifts and 50% on 8-hour shifts). With the 2-3-2 pattern, this means that every 2 or 3 days, people are flip-flopping when they sleep. This can be really tough on sleep and alertness. In fact, it's even worse than most rotating shift schedules that rotate on a weekly basis.
Another problem with the Pitman has to do with the organization's overtime/pay week, since that dictates what days you get off for the weekend. If your pay week begins on Mon, Wed, or Fri, the 3-day weekend will be Sat, Sun, Mon instead of Fri, Sat, Sun. For the night shift, this means you have to work Friday night, so it really doesn't feel like you're getting the whole weekend off.
If your schedule has fixed shifts, I recommend that each shift select it's own pattern. This way the day shift can work the Pitman while the night shift can work something else that is better for alertness and safety. The best choice on the night shift is the 4-on-4-off shift schedule. That's because there are fewer changes from work-days to off-days, meaning a slower rotation of when people sleep. Other 12-hour patterns lie somewhere in between these two extremes: Pitman and 4-on-4-off.
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This is the 6th in a series of posts regarding employee alertness or fatigue in the workplace. This post will focus on employee preferences regarding their shift schedules.
People judge their work schedule, not by when they have to come to work, but by when they can stay home. In short, they focus on their time-off.
What people really want is a schedule that minimizes the conflicts between when they want to be off work and when they can be off work. There is rarely a perfect fit and you will never find a workforce where 100% of the people want the same thing. However, minimzing a majority of the schedule conflicts should be your goal.
Why? When there is a conflict, people will find a way to do what they want to do, often at the expense of sleep. Less conflict equals better sleep patterns, which results in higher alertness and better performance.
There is no pattern that is "best" fo every employee demographic. If you want to know what your workforce wants - ask them.
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