Call center staffing model

A call center staffing model is a framework to determine how to add staff depending on call volumes and how long customers can be on hold.
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What is call center staffing model?

A call center staffing model is a framework to determine how to add staff depending on call volumes and how long customers can be on hold. It often takes into consideration after-call work (ACW) and mandatory breaks.

How to build a staffing framework

The most common way is to use the Erlang C calculator which gives a rough estimate of the number of agents needed to efficiently staff a contact center.

The formula can be accessed in two forms — either as a call center staffing model Excel template that uses macros or through websites available online, but the inputs remain the same. Some of the values needed are:

  1. Number of incoming calls: The average number of calls a contact center receives every day.
  2. Time period: Duration of the time window being considered for the analysis.
  3. Average Handling Time (AHT): Duration of the entire customer call transaction, including hold times, transfers, and after call work.
  4. Service Level (SLA): Percentage of calls answered within Time Period

What additional factors are needed to create a staffing model?

The Erlang C formula was created in 1917, when telephone exchanges included employees who would manually connect with callers. The need arose as it was tricky to quantify telephone operators needed to handle any given call volumes.

However, given that it’s an old concept, other factors include:

  1. Attrition rate: Anticipation of some attrition rate is necessary as call center turnover is a reality that must be expected.

  2. Shrinkage: It is the duration that agents are not on calls either due to time-off or internal factors like meetings and server downtime, must also be considered.

  3. Abandoned calls: Since the Erlang C formula was devised before the concept of abandoned calls, it’s recommended to eliminate the same in the staffing calculations.

  4. Multi-skilled agents: The Erlang C formula is designed for inbound calls only. But certain processes require agents to make outbound calls which should be taken into consideration.