The best way to measure service levels is from the user's perspective. However these user perceptions are measured, the SLA will need to document each service-level indicator used to measure the objectives, and to specify the data source for each. The Key Performance Indicators (KPI) of the service can be applied to the indicators.
- Time lag to resolve a service level issue.
- Volume of work accomplished or speed (e.g. number of concurrent transactions, response time).
- Number of times that subsequent resolution is completed within required period.