Analytical intervals

Erlang for Excel's Erlang C functions refer to the number of calls that a call centre handles, either as arguments or as results. The functions assume that these values relate to the number of calls handled in a sixty minute period. In some cases, call volumes for only thirty minutes are available. Before they are applied as an argument to a Erlang for Excel function, these numbers must be doubled to convert them to hourly figures.

For example, consider the following use of the ErlCAgents() function:

=ErlCAgents( B2 , 180 , 80 , 20 )

which would be used to estimate the number of agents required such that 80% of calls were answered within 20 seconds. The function assumes that the number of calls specified in cell B2 relates to a period of one hour. If cell B2 contained a thirty minute call volume, then the value should be doubled, like this:

=ErlCAgents( B2 * 2 , 180 , 80 , 20 )

The ErlCCalls() function returns an estimate of the number of calls that an inbound call centre can handle in one hour. If a figure for thirty minutes is required, then the function result should be halved.

Similarly, if fifteen minute analytical intervals are to be used, function arguments should be multiplied by four and function results should quartered.