'All lines busy' is an interesting concept, as a caller, the best definition is where you receive the 'engaged tone' or receive a 'busy signal'.  In other words, as a caller, you cannot get into the queue.

If the call centre is extremely busy, is it good practice to give callers a busy signal or allow them to queue for an inordinate length of time?  Obviously the best practice is to allow all your callers through and then have sufficient staff to handle the calls.

As a caller there will be some annoyance at not being connected to the queue, as we remove choice.  If there are large wait times, the caller can choose and use their judgement of any previous dealings with the company, as to whether to continue queuing or abandon.

Where call centres are able to reduce incoming lines, some contrive to do this at busy times - the effect of this is:

• Callers cannot get through
• Service level and abandonment rates are artificially improved
• Accurate customer contact information can be lost
• Call profiles change as the caller cannot get through when they would, ideally like to
• Calls could move to other costlier channels, such as white-mail

There should be an attempt to answer calls when they arrive, to develop good incoming call profiles for resourcing purposes.

Company x regularly reduced lines from 14:00 hrs to 17:00 hrs to improve their call handling position in the afternoons.  This meant callers could not get their call answered when they called.  Call profiles changed as this created a greater demand in the mornings, as callers could not get through in the afternoon.  Over the years, Company x hired more staff for the mornings to answer the artificially higher demand, rather than tackle the real issue of high demand in the afternoons.

Although Automatic Call Distributors (ACDs) are becoming more sophisticated, it is still not generally possible to identify the number of busy signals issued.  This is because the busy signal is issued in the network and not the ACD.  ACDs can identify the percentage of blockage on lines and can, therefore, indicate if a line has been completely blocked.  To identify the number of caller attempts made during a busy period it will be necessary to obtain the information from your network or telecoms provider.

Where busy signals are issued by the ACD, some information will be available.

As with abandoned calls, it is difficult to identify how many 'different' callers receive busy signals, particularly, due to the greater propensity for callers to use the redial facility on their telephones.

See Repeat Call Analysis