1. Calculation functions
  2. All functions
  3. Call center planning functions
  4. ANSWERTIME

The ANSWERTIME function calculates the minimum hold time required to answer a certain percentage of calls, or service level agreement (SLA).

For example, you can use the ANSWERTIME function to adjust the hold time during busy periods.

Syntax

ANSWERTIME(Number of servers, SLA, Arrival rate, Average duration)

Arguments

ArgumentData typeDescription
Number of serversNumberThe number of servers (for example, call center agents) available to process requests.
SLANumberThe percentage of requests that need to be processed.
Arrival rateNumberThe interval between the arrival of each request.
Average durationNumberThe average duration it takes to process each request.

The ANSWERTIME function returns a number, which is the minimum hold time required to answer the percentage of calls specified in the SLA argument.


How the ANSWERTIME function is calculated

The ANSWERTIME function calculates the solution to this equation:

ANSWERTIME(x,w,y,z)=z(log(1w)log(ERLANGC(x,y,z)))ax\text{ANSWERTIME}(x,w,y,z) = \dfrac{z\left(\text{log}(1-w) - \text{log}(\text{ERLANGC}(x,y,z))\right)}{a - x}

In this equation:

  • x is the Number of servers.
  • w is the SLA.
  • y is the Arrival rate.
  • z is the Average duration.
  • a is the offered load, which is y multiplied by z.

Constraints

Time unit for arguments

The Arrival rate and Average duration arguments do not have to use a specific time unit. For example, they can use seconds or minutes. However, both arguments must use the same time unit.

Maximum number of servers

The maximum number you can use for the Number of servers argument is five million.

Call center planning functions are unavailable in Polaris. Learn more about the differences between Anaplan calculation engines.

Related Anaplan functions

Examples

In this example, the Call Centers list is on columns, and line items on rows. The first four line items contain the data for the ANSWERTIME function for each call center:

  • The number of servers available to process requests
  • The percentage of calls that must be responded to within the target response time, or SLA
  • The interval between each request arriving
  • The average duration it takes to complete requests

The Answer time for SLA line item uses the ANSWERTIME function to calculate how quickly requests are responded to given the number of agents, SLA, arrival rate, and average duration.

The Increased SLA line item enables the user of the module to amend the SLA. This is used in formula in the Answer time for increased SLA line item, which calculates how quickly requests are responded to given the number of agents, SLA, arrival rate, and average duration.

Both of the line items that contain SLAs use the Percentage format with two decimal places.


Call Center 1Call Center 2Call Center 3Call Center 4
Number of Servers17243924
Service Level Agreement85%87%92%85%
Request Arrival Rate0.76840.93581.4261.2194
Average Duration18.6723.2524.8717.39

Answer time for SLA

ANSWERTIME(Number of Servers, Service Level Agreement, Request Arrival Rate, Average Duration)

6.94914.812.276.902
Increased SLA90%82%97%90%

Answer time for increased SLA

ANSWERTIME(Number of Servers, Increased SLA, Request Arrival Rate, Average Duration)

9.80219.8319.179.425

Disclaimer

We may update our documentation occasionally, but will only do so in a way that does not negatively affect the features and functionality of the Anaplan service.