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Operational Research

You can always be more efficient

Operational Research is all about using analysis to improve decision making. Dr Angela Moore uses mathematical modeling, statistical analysis, optimisation, sequencing and scheduling techniques to create simple heuristics you can employ to run your operation more efficiently.

angela@oranalysts.com

When 2+2=3!

Have you ever wondered why you continually seem to be either under or overstaffed? You do the calculations and there should be enough. Yet you just can’t seem to get them to match the workload. What is going wrong? It is a good idea to plot how your staffing profile matches your shifts. This way you can see if your shifts are correct for your workload or if you need to change.

When plotting your shifts you should think about how breaks are taken, when management is available and which shifts are your cover shifts. This way you can not only see how many are in each day, but which shifts can be stood down or when you can run short.

The best way to demonstrate is with an example. So let’s take a variable workload, this workload will vary throughout the day. It could be a shop, call centre, or hotel. This workload requires minimal staffing during the night and higher staffing levels during the day. So let’s set the staffing levels to be one during the night and between two and six during the day with the highest number required at lunch time.

We can then plot this workload requirement against the numbers provided by the shifts. So we need a shifts table. Let’s say you use just 8-hour shifts and there are three shifts per day: Early, Late and Night. Then you have one person on night, and five on the Early and Late each day with a Manager on during the day to make up numbers. Would your staffing levels match your workload? On the face of it yes. You need up to six on per day, and you have six on.

shift table 5

This staffing level would require 77 hours per day plus the manager’s hours.

 

shift table 6

 

Figure above plots the staffing requirement with the shifts. The x-axis is from midnight to midnight, so 1 represents midnight to 1am. The red columns are the staffing requirement and the green columns are the staffing levels given by the shifts. Pale green is when they are on their breaks. The breaks are staggered to minimise the disruption. The Manager and Cover shifts are highlighted in blue. The number in work is shown by the orange line.

Now while on the face of it, you had enough staff, the problem is their breaks. With this staffing profile you would be short 1am-2am, 9am-11am, 1pm-2pm, 5pm-6pm by one person and between 6pm and 7pm by two people.

The plot also shows that you are over staffed in the morning between 6am-8am and in the evening after 7pm. Perhaps these hours could be better used during the middle of the day?

So would a slightly different arrangement of shifts give better coverage? The 1am-2am break is on its own. You don’t need anyone to cover the hours leading up to and after so, it’s just something you would have to live with or put two people on at night. The other discrepancies we can do something about. However it is a good idea not to use too many shifts. If you have too many shifts it becomes confusing and takes forever for the shift pattern to rotate through everyone in turn. So let’s see what we can do with just two more shifts and using a similar number of hours per week.

The shifts table below, now has two extra shifts, a Day and an Afternoon shift. So if you had two on the Early and Late shift, still one on the night shift and now three on the Day and Afternoon shift. This uses exactly 77 hours per day, the same as before. Now there are more on over the middle of the day when you need them.

 

shift table 7

So how would the staffing levels compare with the workload now?

 

shift table 8

 

Figure above plots the staffing requirement with the shifts. The x-axis is from midnight to midnight, so 1 represents midnight to 1am. The red columns are the staffing requirement and the green columns are the staffing levels given by the shifts. Pale green is when they are on their breaks. The breaks are staggered to minimise the disruption. The Manager and Cover shifts are highlighted in blue. The number in work is shown by the orange line.

Now the only time when you would be understaffed is when the night person is on their break. The rest of the time you have the correct staffing levels to cope with the workload. Such a small change, makes a big difference to how your operation runs.

If you compare the two graphs you will see that the manager now has a completely different job. Before the entire time the manager was on duty, they were required to cover the workload, and most of the time they were understaffed. Now the manager is still required to cover the workload for four hours of their shift. However the rest of the time they are surplus to the workload. This means that they can do the job they are paid to do and manage everyone else. They can do paper work, meeting with other managers, strategy planning and no longer play catch up.

Then there is how the other shift workers feel on the new arrangements. Before they were either under or over worked half the time. Being under or over worked is stressful and fatiguing. Now they are never over worked (except for when on a break during the night but they are on their break). They are only overworked for a couple of hours and this is during lunch time, so there will be someone on a break to chat too or they can help out during the busiest time. So much more relaxing for everyone. Now when they get home it won’t feel like a relief to be away from work. Instead they can look back fondly on a shift, where they were not stressed and everything went to plan.

If you would like help plotting your shifts against your workload or help setting the correct sifts, please contact us today: This e-mail address is being protected from spambots. You need JavaScript enabled to view it