Over the past couple of weeks, I've had requests from several managers of small groups (5 or 6 people) for help in finding a 24/7 schedule. In most cases, the groups consisted of supervisors rather than workers. They wanted 8, 10 or 12-hour shifts, and they were open to either fixed shifts or rotating shifts.

The managers wanted to see what the different options looked like so they could choose the one that appealled to the most people. I explained that this was not the best way to search for a schedule. The starting point should always be the business requirements. You want to make sure there is adequate coverage and that it matches the workload. You also want to use the resources (staff and overtime) efficiently. Schedule attractiveness can only be pursued after the business requirements are satisfied.

If I assume that these groups needed 1-person coverage on a 24/7 basis, this is what they would see with the six different combinations of shift length and format (fixed vs. rotating shifts):

8-hour Rotating Shifts

1-person coverage requires 4 people working an average of 42 hours a week. With a staff of 5 or 6, they would have 1 or 2 "extra" employees. This extra capacity could be used to increase the coverage, reduce the average hours of work, or to build relief coverage into the schedule to cover absences. The biggest downside is that the schedules are miserable for the employees.

8-hour Fixed Shifts

1-person coverage requires 6 people working 40 hours a week (2 people per shift). There would be 3 days a week in which both employees on a shift would be working, so this is something to keep in mind if there isn't enough room for 2 people at the same time. There would be no extra capacity with this type of schedule. Although not as efficient as 8-hour rotating shifts, they are a little better for employees.

10-hour Rotating Shifts

10-hour shifts always require the most personnel because the group is working 30 hours a day (three 10-hour shifts). I only recommend using 10-hour shifts if the group can take advantage of the 6 hours of overlapping shifts that could be matched to the group's busiest time of the day. 1-person coverage requires at least 5 people working an average of 42 hours a week. If there were 6 employees, this would leave 1 extra. This extra person could be used to increase the coverage on one shift or to build relief coverage into the schedule to cover absences. Even though employees get one more day off each week (as compared to 8-hour schedules), the work patterns aren't that attractive, i.e. quick rotations and lots of 1 or 2-day breaks.

10-hour Fixed Shifts

1-person coverage requires at least 6 people working 40 hours a week (2 people per shift). There would be 1 day a week in which both employees on a shift would be working. During the 6 hours of overlapping shifts on the overlapping day, there would be 4 people at work. If this exceeds the physical capacity of the site, this would not be a good choice. As with fixed 8-hour shifts, there would be no extra capacity.

12-hour Fixed or Rotating Shifts

1-person coverage requires only 4 people working an average of 42 hours a week. With a staff of 5 or 6, they would have 1 or 2 "extra" employees (the same as 8-hour rotating shifts). This extra capacity could be used to either increase the coverage, reduce the average hours of work, or to build relief coverage into the schedule to cover absences. Despite the long days of work, most employees prefer these patterns since they offer twice as many days off and up to half the weekends off.

Summary

Rather than looking for examples of every possible combination of shift length and format (fixed vs. rotating shifts), these groups should first decide what is most important to them:

• Increased coverage. Does the group need more than 1-person coverage for part of the day or during certain days of the week? If so, the desired coverage levels should be the starting point of the schedule search since several options (as pointed out above) have no extra capacity to increase the coverage with.
  
  
• Reduced work hours. Some groups avoid overtime like the plague. They will do anything (including hiring one or two extra staff) so they never have to work more than 40 hours a week. Even though I have argued repeatedly that this is not the best financial approach, many organizations still think the schedule should never have overtime in it.
   
• Relief coverage. If increased coverage isn't needed, any extra capacity can be used to create relief coverage, i.e. time in the schedule available to cover absences. This will reduce the need to cover absences with overtime. Relief coverage works best with rotating shifts since it can be used to cover absences on any shift. With fixed shifts, you would need to build relief coverage into each shift's schedule, so it will require more staff.

Once the priorities are clear, this will narrow down the feasible approaches. There are too many possibilities to discuss here, so if you need more help, please let me know.