Scheduling Insights: Service or Interval-Based Scheduling

Dan Bursik
Vice President of Product Management

Picking up from our last Scheduling Insights introducing the four basic types of scheduling, we will explore Service Scheduling which is sometimes also referred to as Interval-based Scheduling.

It’s an understatement to call this type of scheduling the most commonly understood and practiced type of scheduling. The whole idea of retail labor scheduling was built around scheduling jobs (or tasks) like Cashiering and Bagging. And it’s a very clean, clear process from capturing history in 15-minute intervals and using that history to forecast future needs for those same 15-minute intervals in future days.

Scheduling a Front-End cashier at a supermarket checkout lane is the perfect example of service scheduling. History is captured directly from the Point of Sale (POS) transaction logs and is summarized in 15-minute intervals. At the very least, the register captures the amount of sales performed by cashiers across all Front-End lanes in every 15-minute interval through the day. Better approaches also capture the workload drivers of the items processed and the transactions tendered. And the best of approaches will capture the detailed workload drivers of the item and tender processing so that you know how many items are scanned versus key entered, versus scaled in each 15-minute interval; and how many tenders were made in cash, credit with a signature capture, credit without a signature capture, debit, checks, electronic benefits transactions (EBT) and WIC program transactions in each 15-minute interval of any given day. Other actions that cashiers are required to handle are also captured in the interval data. Examples of those activities would include loyalty card interaction, coupon tendering, removal of security tags, and other miscellaneous activities.

The bottom line of service or interval-based scheduling is that history is captured and detailed in each 15-minute interval. Forecasting then utilizes this history to develop a workload for each 15-minute interval. Labor standards translate that workload into raw labor demand. Allowances and staffing parameters (which we will discuss in greater detail in upcoming sessions) then translate that raw labor demand into your scheduling requirements and workplan.

The important concept for Service Scheduling is that the forecast is detailed to the 15-minute interval and the work is tied to each specific interval. It doesn’t do you any good to overschedule cashiers in the morning if customers need to be cashiered in the evening. Two wrongs don’t make a right! Each interval stands on its own work requirements.

For most automated scheduling systems, this is very straightforward. Your forecast, hopefully as detailed as possible, is summarized in each 15-minute interval. Once you apply your standards to that interval data in each 15-minute bucket you have the engineered hours of work content or the raw demand hours required to perform the anticipated workload volumes.

Why are these not the final scheduling requirements or final staffing demand? That’s because there are several more staffing parameters that need to be applied before we finalize the requirements for scheduling. These are the most widely used parameters for Service Scheduling:

Sustainment – What happens when you have 4 intervals requiring 4 cashiers, followed by another interval calling for 7 cashiers, and then several more intervals of 4 cashiers. How can you work your schedule to go from 4 cashiers to 7 cashers and back to 4 very quickly? Is that really what is required or is that a datum anomaly? Most systems handle this by looking both backward and forward from each interval to determine if the requirement is sustained over time. This can also be referred to as a smoothing factor as the result is that it smooths or normalizes the curve of interval requirements into something that can be better scheduled.

Rounding – Although most systems schedule on the 15-minute interval, what happens when your demand is for 2.3 cashiers? Is that 2 cashiers or 3 cashiers? Rounding, or various processes associated with rounding, determine the final whole number requirement for each interval.

Minimum or maximum requirements – It’s fine for the system to calculate that early morning demand calls for only 0.4 (four-tenths of one cashier) in the 7:30 time interval. But what if you require at least one dedicated cashier at that time? If you have a minimum staffing requirement, then anything less, whether it meets the normal rounding factor, must be increased to the minimum of 1. Suffice it to say that the same holds true on the maximum side. It’s hard to schedule 7 cashiers if you only have 5 registers to open.

The beauty of Service scheduling is the direct relationship from the forecast to the necessary placement of the hours. There is no interpretation. The forecasted workload you anticipate servicing at 3:45 is the direct basis of what you need to schedule at 3:45, barring minor adjustments for staffing parameters, like those I have mentioned above. This direct relationship between the forecast data, the workload and the scheduling requirements, the workplan, defines Service Scheduling.

What happens if that relationship does not exist at the 15-minute level? We will take up the next type of scheduling, Production or Non-Service Scheduling, in our next installment.

In his series, Scheduling Insights, Dan Bursik provides insights and strategies around effective retail labor scheduling, addressing a diverse array of challenges and topics. To read the previous edition, click here. To search for all editions of Scheduling Insights, click here.