Hi!

I am learning concept of call center WFM. There are lots of tools such as Erlang and lot of online calculators available on the Internet to calculate the number of agents required.

My question is if we decide to use only excel then what all parameters we should think of to arrive into a decision which could be close to perfection?

For example : If I have to answer 9000 calls in a 24/7 pattern then how many agents will I require? Lets say I have SLA 80% Avg Speed to Answer 20 seconds and Average Handling Time 3 minutes.

Mahesh, In my last business years ago we used excel to schedule until we had over 80 agents and then purchased WFM software as the business was expanding further which was much better. In my current we are still using excel both to forecast and schedule for half hour intervals.

Our biggest call centre receives about 7,500 calls inbound per day, AHT 3.5 mins. Despite being very, very basic (track interval trends over a period of time and use this to forecast, use AHT to determine agents needed on the phones per interval etc) it really does work for us, even though we made the spreadsheets when we only took about 3,000 calls per day, we achieve our targets. However, in my opinion Excel is very limited if you want close to perfection and/or if your typical customer calling patterns are unstable and/or if you have very tight headcount or staffing cost budgets to hit.

Mahesh, just looking at the example you have stated, if you load on to excel the erlang add-in(search on google) then you will already have the formulas to determine using erlang what your 'pure' requirement is using that level of information, that is to say how many agents you would need to answer the call volume on the day.

IMO there are 2 areas where erlang in excel doesn't really work, they are cross skilled environments where not all agents have the same skill sets and it also doesn't take in to account shrinkage; this normally needs to be added manually.

This is not an exhaustive reply and there are other considerations to allow for, but if you are single skilled or all agent skills are equal you can get a fairly accurate forecast at an intraday level.

Hi Mahesh

I wasn't clear with what you menat by SLA 80% Ave spped to answer 20 secs so have presumed the below

At 9,000 calls per week (you do mean per week don't you?), 24/7 opening and answering 80% of calls in 20 secs at 3 mins per call then you need about 31 FTE based on a 37.5 working week and normal shrinkage assumptions.

If you are aiming at an Ave speed to answer of 20 secs, then the requirement goes up slightly to 33.6 FTE.

Eamon

Without the risk of sounding daft... with no use of erlangs and excel sheets..can u work out the FTE's reqd if we have the number of calls , AHT and call answered time as queried by Mahesh? how did u work out the FTE number below ?

if yes..could u please let me knw of the same. Looking fwd to your reply

I have a spreadsheet which I can use to quickly size call-centres using erlang, a normal call distribution and shrinkage. Means that I can very quickly come up with the an accurate number of FTE required for a call-centre.

Eamon

Thanks for the rever Eamon...so is erlang the application u using to calculate this?

could u tell me the site name where i can download this.

Yep, I use the erlang add-in for Excel within a spreadsheet that I developed. The add-in is available free from a number of sources try www.erlang.com for starters.

Eamon