To illustrate how KPI formula work imagine a scenario where you are collecting the number of unresolved critical issues from a Service Desk application but you are more interested in what percentage of all unresolved issues are critical. This is a simple example of how ServiceClarity can combine two metrics into a KPI using the formula:

` % critical = 100 * (number of critical / total number unresolved) `

Within ServiceClarity the javascript for the above formula might look like this:

- On line 1 the special ServiceClarity variable
*metrics*is used to get the last known value for the metric: total number unresolved. - On line 2 the same
*metrics*variable is used to get the last known value for the metric: number of critical. - On line 4 the two values for critical and and total issues are combined and returned as the calculated value for the KPI.