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

 Argument Data type Description Number of servers Number The number of servers (for example, call center agents) available to process requests. SLA Number The percentage of requests that need to be processed. Arrival rate Number The interval between the arrival of each request. Average duration Number The 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:

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

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.

## 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 1 Call Center 2 Call Center 3 Call Center 4 Number of Servers 17 24 39 24 Service Level Agreement 85% 87% 92% 85% Request Arrival Rate 0.7684 0.9358 1.426 1.2194 Average Duration 18.67 23.25 24.87 17.39 Answer time for SLA ANSWERTIME(Number of Servers, Service Level Agreement, Request Arrival Rate, Average Duration) 6.949 14.8 12.27 6.902 Increased SLA 90% 82% 97% 90% Answer time for increased SLA ANSWERTIME(Number of Servers, Increased SLA, Request Arrival Rate, Average Duration) 9.802 19.83 19.17 9.425

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