A Simple Retail Staffing Model

Dr. Wayne J. Cosshall
5 min readNov 23, 2021


Finding Better Systems With Some Lateral Thinking

Photo by Clark Street Mercantile on Unsplash

My wife and daughter both work in retail. For my wife this is her career. For my daughter it is something she does when there is not work on for her in the film industry. Both have worked across many businesses, from national chains to small, single location stores. A conversation with my wife over whether they had enough casual staff for her store (she’s the acting manager) got me thinking about systems.

A little context is in order before we go on. We are located in Melbourne, Australia. At the time of writing we have just emerged from Covid-19 lockdown as our vaccination rate closes in on 90%. Retail has just opened up to in-store shopping, as has hospitality. But as has been widely reported, something has happened to people during the Covid crisis and people are either leaving their old jobs or are much less willing to put up with an unsatisfactory situation. So, things are challenging.

Retail Staffing

Let’s setup an example staffing profile so we have something to discuss. Let us say that this store has one full time employee (38 hours per week), two part time employees (19 hours per week each) and a collection of six casual staff. Just in case this terminology is not the same where you are, a casual worker is someone who works by the hour and has no set allocation of work.

Step 1 — Hours Open

The first step is to work out how many hours the store is open per week. Monday to Wednesday the store opens at 9am and closes at 5:30pm. Thursday and Friday it opens at 9am and closes at 9pm. Saturday it opens at 9am and closes at 5pm, while on Sunday it opens at 10am and closes at 5pm. So that is:

8.5 x 3 + 12 x 2 + 8 + 7 = 64.5 hours per week

Step 2 — Shop Open Staff Hours

As you would expect, a store needs different numbers of staff on different days and at different times. Let’s assume that Monday and Tuesday mornings are quiet, and so you could have just one person in the show for the first 2 hours, but then after that you need two people. For Monday and Tuesday that is

2 days x 2 hours x 1 staff + 2 days x 6.5 hours x 2 staff = 30 staff hours

Wednesday needs two staff all day, giving

1 day x 2 staff x 8.5 hours = 17 staff hours

Thursday and Friday get busy, and so they need 3 staff for the first eight hours of each day and four staff in the evening, giving

2 days x 3 staff x 8 hours + 2 days x 4 staff x 4 hours = 106 staff hours

Saturday and Sunday are both very busy days, and so need four staff at all times, giving

1 day x 8 hours x 4 staff + 1 day x 7 hours x 4 staff = 60 staff hours

If we add all those days up, we get

30 + 17 + 106 + 60 = 213 staff hours per week

Step 3 — Casual Staff Actual Availability

Now we get to the crunch of the matter. The area manager in the triggering discussion believed that eight casual staff is plenty. And in many situations that would be exactly the case.

But for this calculation to be meaningful, it has to be based on the real situation. If we look at the situations of the six casual workers, they are something like:

· Mary is working three jobs, so on a typical week she will only work 8 hours at this shop

· Jo is caring for a sick parent and husband, and so can only reliably work 4 hours a week

· Patrick is building his own business, and so can only work 30 hours a week

· Adele is very unreliable and only really does 2 hours a week

· Mohammed is keen for work and will do 27 hours a week

· Karen is studying and so can do 12 hours per week

Step 4 — Available Staff Hours

If we now add up the full time, part time and casual staff actual work time we get

38 + 2 x 19 + 8 + 4 + 30 + 2 + 27 + 12 = 159 staff hours

Step 5 — The Good or Bad News

Now we compare the Shop Open Staff Hours from Step 2 with the Available Staff Hours from Step 4. If the Available Staff Hours are equal to or greater than the Shop Open Staff Hours then we are ok. If not, we are in trouble.

In this case the shop needs 213 staff hours per week, but we can only rely on the available staff to provide 159 hours. What happens in this situation? Everyone is stressed, staff consider leaving (which will only make it worse), the store is sometimes understaffed, leading to dissatisfied customers. All around, this is a bad situation.

A larger pool of casual staff would turn this situation around completely. Three more casuals willing to work at least 20 hours a week would change the available hours to 219, more than the required 213 staff hours, though only just.

Using Current Data for Decision Making

The thing is, twelve months ago, the six available casual staff might have nicely covered all required hours and have been asking for me. But people’s lives change. Parenting duties change, study plans change, spouse’s workloads change, people get sick, interest rates rise and so on. What this means is that you must make decisions based on current data, collect new, more accurate data at regular intervals and be open to any warning signs that things may have changed.

As a manager of retail operations, if I received feedback from staff feeling the store was understaffed, I would want to reassess actual staff willingness to work and then run the above calculations again. And the real situation is actually worse. When big sales are on, or the super heavy shopping periods are on the actual number of staff required will be higher. This is why, in Australia, stores advertise for and put on some number of Christmas Casuals as they are called, over and above the normal ones.

Do Retailers Do These Calculations?

Since I don’t work in retail myself, I have no idea if these sorts of calculations are normal or not. I also don’t know if this is a standard and widely used method, taught in text books of retail trade. But just in case I’ve invented something, I’m going to call this Cosshall’s Staff Coverage Assessment ;)

I know many businesses do very complex analysis of stock levels and such. But I am left wondering if too many seemingly obvious and easy decisions, like how many casuals you need, are left to feelings when a pretty simple calculation would allow much better transparency and accuracy.

In fact, I can see how this could be further improved. With access to the payroll system, it would not be hard to build an automatic system that looked at a rolling average of hours that casuals actually work and then use then to run the calculation. Such automation could readily provide trend information to managers that just might identify a growing issue before it gets really noticed in the day to day stresses and chaos of retail operations.

Let me know if this was useful.



Dr. Wayne J. Cosshall

Artist, Author, Druid, Educator, Polymath, Technologist. CEO TechnoMagickal. Co-Founder, CTO and Chief Learning Officer, TMRW Group. Ed Lead, Octivo Australia.