In order to accurately calculate the FTE requirements, interval data must be identified for the number of calls answered by the specified group of agents planned within the schedule. You would need to know the call volume and the AHT, per interval. To do so, you would use the historical data available. Ultimately, if shrinkage data is also available per interval, this would be useful in obtaining requirements from a broader perspective.. this aspect we will discuss later.
Depending on your phone system setup or capacity, historical data by interval may not be available for more than 30 to 60 days. I would therefore recommend that you test your system, and archive if needed, in a tabulator. Most likely, you will want to create your schedules for the upcoming few weeks. Depending on your call centre model, the last 4-6 weeks may be very similar to the next 4-6 weeks. If not, you may want to verify the model of those weeks from previous year(s). Again, the data availability is key…
Depending on the type of schedules you are creating, classic 5 X 8 schedules on 5-day week vs 4 X 10 on a 7-day week, you may want to gather your interval data in different ways.
For a classic 5-day week, where agents always have the same schedule, you would want to create your model on an average day. To do so, you would calculate the average call volume per interval, and a weighted average for the AHT.
For a 7-day week, where agents have different scheduled start times, you would want to create your model for each day of the week. This is more time consuming, yet necessary per accuracy of your calculations.
Now that you have your model in place, you would need to calculate the FTE requirements per interval. To do so, you should use your WFM system, or Erlang C for Excel, as an example. To find FTE requirements, Erlang C would use the call volume and AHT of the interval, the TSF objective, and the TSF threshold.
From this FTE requirement, you would then need to apply your shrinkage. Please note, your historical shrinkage may be (is) different per interval. This being said, you may want to apply your average shrinkage to each interval. For example, if you have for the same period a 30% shrinkage, you would multiply the FTE requirement by 1.3. Please note, I think you should be careful with opening and closing FTE requirements. For example, let’s take an example where you have 3 agents opening your call centre at 8am. If one of those noted agents are on vacation the following week, would you be proactive and replace the agent with another ? If so, I would not apply the same shrinkage percentage to this interval.
From this FTE requirement, with shrinkage, you would then build schedules based on the number of agents you have in this group. Please note, I will be posting on the different types of schedules in the near future.
If you have more agents/schedules than required, you should consider confirming any pending time off waitlists for the specified period. Therefore, allowing an increased availability to confirm time off requests, encouraging more time for off the phone activities/trainings etc.
If you have less agents/schedules than required, your business would then need to make a decision: Are you staffing at the bare minimum during some intervals, or are you averaging the gap throughout the day?
Once you have the schedules created, you would then have the agents bid on the schedule patterns accordingly. There are different types of bidding processes: Based either on seniority, rotating schedules, performance etc… We may also encounter a different mix of each. The pros and cons of each process will be highlighted in a future post… stay tuned.
