Schedonomy® Science

Lets try the same example but with a 9-hour duration maximum. Is it possible to fit 3 shifts of 9 hours instead of 4? This would reduce the number of part-time employees that we would need. Right? And we  should have enough hours since three 9-hour shifts makes 27 hours available and we have 26 hours of work.

The table below shows that result. We pencil in 9 hour from the beginning of the day (shift 1) and 9 hours from the end of the day (shift 2). Notice that shift 3 starting at 9a covers the rise and fall of workload at the beginning and end of the day very nicely. But there is a catch. Notice the effect on the coverage. Although there is enough hours for the whole day, they are not distributed according to the actual workload. Coverage shows that there is one employee extra for 3 hours in the afternoon and that there is one missing employee during the peak time of 3p to 5p.

This is just to show that peaks and valleys have a significant influence on how the shifts are carved in a day.

The example above was simple. Real workload can produce easily up to 25 shifts per day. It becomes quite difficult to determine the best start and end times when these situations occur. Here are a few simple rules to help carve the shifts when workload is big:

1. Determine the night shifts first. Usually, night is when workload is at its lowest and night shifts are the ones most employees dislike. They are known to disrupt sleep patterns and cause fatigue.
2. Work around the peaks. Identify the highest demand in work and pencil in your shifts going both left (for a shift ending after the peak) and right (for a shift starting before the peak). You can determine the final duration of each shift once you’ve established the number of shifts you have.
3. Determine what is good enough for coverage. If there is a need for 20 employees and you have 19 shifts for that hour, that’s probably good enough. But on the other hand if you need 2 employees and you only have one, you probably need to cover that hour.
4. Merge the shifts. After the initial carving, you can take a look at shifts that could be merged. This happens when you have a lot of shifts and you don’t necessarily look at long shifts when you are penciling them in. You can reduce the final count by merging a shift that ends at or near the start time of another shift.

Time independent workload

For time independent workload, there is no need to carve shifts based on start and end times. You simply need to decide when

Mixed workload

A mixed workload where both time dependant and independent hours need to be assigned will merge both tables together.

The carving will all depend on the profile and the type of workload. For time-dependant workload, a planner needs to transform the requirements curve into blocks of work. Best way to proceed is to view the work as a matrix of work versus a workload. The horizontal axis is time and each column represents the resolution of workload breakdown you decided upon in chapter 3 (remember?).

Let’s look at the grid below. The grid has a one-hour resolution (the workload resolution). The required workload for a specific activity is indicated just below. Right under the workload is the coverage. The coverage represents the number of employees present and productive for that activity. In our grid, at this point in the process, it represents the number of shifts covering the hour. Each row under that represents one shift.

In this example, the workload is small to make it simple to explain. You’ll notice that it is very easy to reproduce this example in a spreadsheet tool. Makes things easier to try out and modify the shifts (making them longer, shorter, etc). We’ll also consider that the longest possible shift is 8 hours. Anything over 8 hours is overtime and shouldn’t necessarily be part of this step.

First thing to do is to determine the first shift start time; in our example, we start at 6am when the workload starts. We then pencil in the number 1 in each cell that the shift will cover. When you pencil in a 1, you need to add 1 to the coverage row since you just added a shift. Lets pencil in the shift for 8 hours.

Moving right along, we notice the workload going up again at 9a and again at 10a. Therefore, we can pencil in shift 2 starting at 9a and shift 3 starting at 10a for a duration of 8 hours.

We now move on to shift 4 which would start at 3p since that is when the workload goes back up. This would make shift 4 very short (4 hours) since our workload for that day stops at 7p.

All we did so far was to pencil in three shifts of 8 hours that have different start times based on what the workload requires and one shift of 4 hours. If we compare the workload (what’s needed) and the coverage (what we scheduled), we notice that at 12pm and 1pm, there is one extra person.

There are many things a planner can do to reduce this back to 2. We can reduce shift 1 by two hours or we could add lunch breaks for shifts 2 and 3. Let’s leave the breaks out of it for now and reduce shift 1 by 2 hours.

Of course, these numbers are laid out this way so that they fit nicely in the example. Notice how shift ends and shift starts overlap to cover the peaks of demand. Also notice that with 26 hours of workload, we get 4 shifts of different durations because of these peaks.