I often get asked, "How to Calculate FTE for Offline Queue?" with a specific TAT.
Today, in this article, I'll try my best to solve the problem with some practical illustrations on calculating the FTE requirement.
Let's start to explore!!
While we are trying to calculate the FTE for Offline Queue, the only thing which confuses us the most is the TAT which stands for Turn Around Time.
So, What is Turn Around Time, and how is it decided?
Turn Around Time is the minimum or the Target time required to complete a task. The simplest way to calculate the Actual TAT is Turn Around Time = Exit Time - Arrival Time.
The Turn Around Time is decided using a Time & Motion Study during the initial stages.
Time & Motion Study is a systematic observation, analysis, and measurement of the separate steps in the performance of a specific task to establish Turn Around Time and Productivity (explained at the later part of this article).
The study also aims at improving the TAT and Productivity.
Once a proper Time & Motion Study is established, the Turn Around Time is decided, becoming a target to achieve.
Some of the examples of Turn Around Time for Offline Queues are as below
100% in 4 Hours
80% in 2 Hours
100% in 24 Hours
100% in 48 Hours etc.,
Now we have the Target Turn Around Time. The next step is to Calculate how many FTEs are required to do the job.
I have attached an excel file at the end of this article, which explains all the below calculation methods.
Now we have the Target Turn Around Time. The next step is to Calculate how many FTEs are required to do the job. But, before that, let's look at some parameters required for the calculation.
Productivity
While doing the Time and Motion Study, the firm will also decide how many tasks can be processed by an agent at a specific time, for example, 20 tasks per day. This is called Productivity.
Although there are many other terms for this, we will refer to Productivity for this article.
Two major examples of Productivity are shown below
20 emails per Day
15 emails per hour
Now, the above Productivity can be converted to AHT with just a simple calculation.
20 emails per Day = (3600*8)/20 = 1440 Seconds
15 emails per hour = 3600/15 = 240 Seconds
At the same Time, the AHT can also be converted to Productivity with the below calculation
1152 Seconds = (3600*8)/1152 = 25 emails per day
300 Seconds = 3600/300 = 12 emails per hour
The 8 is the shift length, and if you want to change it, you can. Also, if you're going to calculate AHT in Minutes, please use 60 instead of 3600.
Occupancy
Occupancy is the parameter where things get tricky. In Immediate Service Queues such as Inbound, Chat, etc., the occupancy is an output derived from Erlang C. It is calculated as a weighted average of all the interval-wise (15 mins or 30 mins or 60 mins) occupancies derived using the Volume, AHT, and the Scheduled FTE.
But will it be the same for Offline Queues? I don't think so
If you look at the Excel Attachment below, I have considered Erlang to calculate the ideal Occupancy for 100% in 2 Hours TAT. Please refer to the "Erlang Method - ASA" tab.
I have used the ASA formula to find the agents required for 15000 transactions spread across a week in an interval level with an AHT of 300 Secs. The Macros are edited a little to accommodate for the Interval Length.
As you can see from the Excel file, the occupancy is coming at 94.86%. Is this a good occupancy to run at? Not at all. The agents would end up burning out, which leads to higher attrition.
If your TAT is around 80% or 70% in 2 hours or 4 hours, you can use the SLA formula to find the agents required. Please refer to the "Erlang Method - SLA" tab.
As you can see from the Excel file, the occupancy is coming at 96.47%, even for the SLA scenario, which is definitely very high.
Therefore for Offline Queues, it is always suggested to go with standard occupancy of 85%, which will be ideal.
You can change the TAT, Volume, or AHT in the file to see the change in Occupancy for yourself.
The Final Step!!
FTE Calculation
There are multiple ways to calculate FTE for Offline queues, and I've tried my best to show as many ways as possible. But, first, refer to the Tab "Workload Calculation" in the excel file.
Method 1 - Using AHT This is a simple Workload method where the Volume, AHT in Secs, and Occupancy of 85% is used to calculate the FTE Required without Shrinkage.
Method 2 - Using Hourly Productivity If an agent has a target of 12 emails per hour, that means we would know the total email an agent can complete in a week just by multiplying 12 times 40 hours times occupancy of 85%. We found that an agent can complete 408 transactions a week by this calculation. Therefore we would need 37 agents to do 15000 transactions (i.e., 15000/408).
Method 3 - Using Daily Productivity If an agent has a target of 96 emails per day, that means we would know the total email an agent can complete in a week just by multiplying 96 times 5 days times occupancy of 85%. We found that an agent can complete 408 transactions a week by this calculation. Therefore we would need 37 agents to do 15000 transactions (i.e., 15000/408).
Now, what if the productivity which was calculated using the Time and Motion Study already had Occupancy baked into it?
As told earlier, the Time and Motion study is a systematic analysis of a particular task. While studying the productivity, the firm may have already accounted for all the idle Time in between; therefore, we don't have to add the occupancy again.
However, this has to be confirmed by analyzing the study if we have the source or asking the right person how the productivity target was determined.
Let's see how to calculate FTE when the occupancy is already a part of the AHT.
Method 4 - Using AHT This is a simple Workload method where the Volume and AHT in Secs are used to calculate the FTE Required without Shrinkage. Method 5 - Using Hourly Productivity If an agent has a target of 12 emails per hour, that means we would know the total email an agent can complete in a week just by multiplying 12 times 40 hours. We found that an agent can complete 480 transactions a week by this calculation. Therefore we would need 31 agents to do 15000 transactions (i.e., 15000/480). Method 6 - Using Daily Productivity If an agent has a target of 96 emails per day, that means we would know the total email an agent can complete in a week just by multiplying 96 times 5 days. We found that an agent can complete 480 transactions a week by this calculation. Therefore we would need 31 agents to do 15000 transactions (i.e., 15000/480).
Conclusion
To conclude, while we are calculating the FTE for Offline Queues, I would not consider Erlang unless the TAT is 1 hour or less. I would always consider a standard occupancy of 85% provided if the Operations team accepts the same.
Click below to access the Excel file.
Thank you for reading, and stay tuned😊
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