Most shift length comparisons look at 8-hour shifts vs.12-hour shifts. They also focus on the advantages or disadvantages from the employee perspective. This post will address 10-hour shifts vs. 12-hour shifts from a management perspective.
10-Hour Shifts
The primary advantage of 10-hour shifts (and only justifiable reason for considering them) is that they enable organizations to match their coverage with a variable workload. They are able to do this because the shifts overlap one another for 6 hours a day. There are three workload patterns that can be accommodated with 10s:
- The workload is higher for a single 6-hour period every day.
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The workload is higher for 12 hours every day.
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The workload is higher for 16 hours every day.
Many police and dispatch centers have workload patterns like these, which is why you will find 10-hour shifts used so often in these organizations. Companies with steady workloads should never adopt 10-hour shifts. For them, the overlapping shifts are a waste of manpower.
The primary disadvantage of 10-hour shifts is that they require more staff than 8s or 12s since they require the employees to work 30 hours a day (three 10-hour shifts) instead of the usual 24 hours. As a result, the organization would have to employ 25% more people with 10s than with 8s or 12s. Other problems with 10-hour shifts are covered in more detail here: http://www.shift-schedule-design.com/10-Hour_Shifts.
12-Hour Shifts
The key advantage of 12-hour shifts is that they will produce maximum coverage from a given set of workers. Sometimes organizations can use this "extra" output to cover absences without resorting to mandatory hold-overs or call-ins:
- They can produce coverage that exceeds the minimum requirements.
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They can build relief coverage into the schedule.
The biggest downside of 12s is that they require overtime in the schedule. Half the work weeks are 36 hours (three 12-hour shifts) and half are 48 hours (four 12-hour shifts). There are ways to eliminate or minimize this, but they are rarely worth the effort, e.g., see http://www.shift-schedule-design.com/Blog?m8:post=12-hour-shift-schedules-with-no-overtime.
Alternative Scenarios
If the organization has a variable workload, 10-hour shifts might be the best choice. The three situations in which 10s work best were listed above.
If the organization has a steady workload, 12-hour shifts are the obvious choice. 10-hour shifts would be too wasteful since they would require more staff than 12-hour shifts. For example, if the organization needs 4-person coverage on a 24/7 basis, this would require 21 employees with 10-hour shifts and only 16 employees with 12-hour shifts. That's 31.25% more personnel.
If the organization has limited staff relative to its coverage requirements, 12-hour shifts are the best choice. Using the example cited above, an organization with 16 employees could produce 4-person coverage with 12s but only 3-person coverage with 10s.
If the organization has a high absence rate and sufficient staff, they can use 12-hour shifts to either create extra coverage or relief coverage in the schedule. Let's say they have 16 employees but only need 3-person coverage. With 12s, they could either increase the coverage on each shift to 4 people or, if they have rotating shifts, build relief coverage into the schedule.
If the organization has both a variable workload and a high absence rate, which is common with many police departments and communication centers, the choice between 10s and 12s becomes more difficult. 10s are best for the variable workload, whereas 12s are best for squeezing extra coverage out to compensate for absences. The choice depends on which is most important to the organization, though it often boils down to what they can afford which usually means 12-hour shifts.
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