SLA and Abandon Formulas In Erlang

SLA and Abandon Formulas In Erlang

I have a question regarding SLA and ABN formulas in Erlang.

I try to get the expected service level and abandon level for a day, with 30 minute breakdown. Therefore, I calculate both values by using Erlang for every interval. I get the total amount of calls in SL and Abandoned.

But my question is, does SLA formula have into account abandon?

Example. In a 30 minute interval, I expect to have 50 offered calls. I have 9 agents scheduled. The SLA is 80/20 and AHT 240 secs.

What I get is 74,2% SL (37 calls in SL) and 7,3% ABN (4 abandoned calls)

So, the composition for that interval would be:

50 offered calls

4 abandoned calls

37 calls handled before 20 seconds (in SL)

9 calls handled after 20 seconds

Is it correct? Or do I have to apply SLA only for 46 call (50 offered – 4 abandoned)? SLA formula is considering that there will be 4 abandoned calls?

I appreciate you help.

Question asked by Carlos

SLA and Abandon Come From Two Formulas

SLA and Abandon come from two formulas – you should read this article: A Beginner’s Guide to the Erlang A Formula

The Erlang Calculator works out the SLA on the calls offered, not the calls abandoned.

The problem is that if you work on , for example 46 calls (50 offered, 4 abandoned) then this would lead to understaffing, which is already a major headache for the industry.

With thanks to Jonty

Author: Jonty Pearce
Reviewed by: Megan Jones