It is common practice in call centres to assume abandon callers do not call-back.  Why is this the case?  Well, we use Calls Received (Calls Answered + Calls Abandoned) in all our resourcing forecasts.

Whilst it must be accepted some callers will not call-back, particularly, in sales environments, where a lost call can become a lost sale, this is not necessarily the case in customer service environments.  Here, callers may attempt any number of times, particularly with redial facilities on telephones.  Put yourself in the position of waiting in a queue, you may keep redialling dependent upon the urgency of your call.

If you are dealing with a poor service provider, you may try a couple of times to get through, and then commit your enquiry to writing. 

Some call centres may assume an abandoned caller may try a total of 2/3 times - there cannot be a standard here.  However, to assume every abandoned call is lost, inflates the Calls Received figure.

All in all, this can lead to over-resourcing, when using Work Force Management (WFM).  WFM uses Erlang C, tele-engineering traffic calculations, which assume nil abandon.  You can, therefore, see how the Calls Received figure becomes inflated, by assuming abandons never get through.