Category Archives: Scheduling

Erlang ‘C’ & Scheduling for Call Centres – IV

The key things you need to remember if you’re using Excel or any staffing program is to ensure that your minimum coverage matches your expected call volumes and coverage levels based on the Erlang ‘C’ formula and tools mentioned earlier.  It ill behooves you to have too many resources at 2am when you’re only expecting 1 phone call and your SLA is 2hrs!

  1. It might pay dividends for you in this instance to use an outsourced party where your call is answered by the equivalent of an ‘order taker’ so that the customer at least is able to speak to someone and have an incident opened for them and then their issue is actually only addressed when your staff resume regular operations.  Remember the points I’ve already made about SLA, Tiered Customers and Escalation Matrix‘.  This actually brings up another point that’s worth discussing and that is ‘On Call Coverage’ which I will address in further posts.
  2. Scheduling Employees 2000 – a step up from the Excel route is this software package.  Published by Guia International, this application is fairly inexpensive and is extremely easy to use.  It allows you to input details of a single department or team and ensures that you have the appropriate coverage based on time of day.  It has nice printouts and although not fully “web-enabled” it is easy enough to ensure that your staff have an up to date copy of the schedule by publishing your schedule online. With the ability to track time and labor costs by the hour and week as your schedule.  And simple drag/drop scheduling that allows you to schedule in 15min increments accounting for breaks.  You are easily able to see at a glance when your staffing levels do not match up with your required coverage.  Now there are a host of other scheduling applications available online and I will try to review some other packages in the coming weeks/months but this one does come highly recommended by me!
  3. When to Work (W2W) – on the high-end side and with a host of features, W2W is a very robust application.  It is fully web-enabled which means that not only are your staff able to view and access it from anywhere, it simplifies your reporting and control also.  It is very customizable and not only has some very good automated staffing calculators based on Skill Based routing and also allows for staff schedules that are restrictive due to other requirements – ie. someone is not able to work evenings on mon/wed/fri but is available any other day.  You can input these restrictions into the system and then forget about them as the system will then NOT allow you to schedule them for the times they are unavailable.  Notifications are provided to staff whenever a change is made to their shift and you also have the capability of utilizing a company bulletin board – for example, announcing a special schedule due to the staff Christmas Party! – when publishing schedules that impact multiple departments and teams.  One of the best features and most useful of When2Work is the ability to have different schedules by diffferent teams/skills all contained inside the same application.  The ability to drag drop shifts and providing staff the flexibility of trading shifts with similarly skilled employees is also a great feature.  Although significantly more expensive, when you have reached a certain size, having this sort of a tool available to you will prove a definite boon!
I hope that this has been useful information to you – if you have any questions, please feel free to contact me and I will do my best to answer you or at least point you in the right direction.

Erlang ‘C’ & Scheduling for Call Centres – II

Escalation Matrix –

OK, great, we’ve got an SLA, we have the appropriate staff in place to take the call when they make it … now, what happens if they are not able to fix the problem?  Easy!  You get the problem to the right people that can fix it in a timely manner.  This is where the escalation matrix comes into play.

Assuming that its 2am and you’ve got a Tier 1 customer (remember, your definition of Customers was made before this) that has no telephone service (hard down etc…).  This is impacting them and potentially costing them $$$/hr.  Your engineer has taken the call and started working on the issue.

Now as this company is paying you lots of money for the service (that IS why they are Tier 1 after all), you need to ensure that you’ve got ALL the right people available and working on their problem as quickly as possible.  A sample 2 Stage Internal Escalation Matrix that I’ve used with great success in the past is presented below.    You will need to have a separate matrix that is provided to Customers which I shall provide you with in a later post.

Provided below is a table detailing the different groups & times that they need to be notified at based on the problem & its impact.

Please note – its fairly easy to remove the additional Escalation Group step mentioned below, if your escalation is to only one group! This type of structure only applies to larger companies where the problem and responsible party could be in a variety of different locations. The groups mentioned below also vary based on the type of organization – for example, Ops/NOC is applicable to a telco environment but not necessarily a manufacturing one.


Erlang ‘C’ & Scheduling for Call Centres

Erlang ‘C’ is a Nobel winning formula used in the Call Centre and Operations industries to determine the correct and appropriate level of staffing based on key call metrics.  The scary looking formula for this is below and the even scarier explanation from Wikipedia is here.

From a Call Centre and Staffing Point of view, the primary elements considered are as follows:

  • Average Talk Time
  • Calls/per specified period (15min is a good benchmark)
  • Specified Service Metrics or SLA (ie. 80/20 <- 80% of calls answered in 20s or less etc…) … correspondingly, you want to consider your abandon %’age here also.  Are you willing to accept that some of your customers will hang up?  If so, how many & consider what impact that will have on your business in the long run!

With this information in hand and using the formula, you are able to determine how many resources you need in a given period to meet your customer demand.  Using some free online tools (links provided below), you are also able to determine your required resources based on a specified timetable and rotation.  For example, if the formula states you need 8 resources between 8am-9am and you are running a 24/7 call center the actual number of staff you need to employ is ‘X’.

Some Good Free Erlang ‘C’ Calculators –


With this in mind, you still need to plan for excess capacity relevant to staff absenteeism either planned or unplanned.  So although the formula only called for 8 staff & your overage based on a 24/7 call centre is ‘X’ … you should actually plan to have ‘Y’ resources available to cover these gaps!!