I manage a support team in a company where Agile model is used. The problem is that loads of tickets remain open because developers don't have time to fix bugs and this results in users being frustrated. I would like to implement SLA for ticket resolution to ensure that incidents and requests are resolved in a timely manner but from what I understood, SLA are not really in line with the Agile way. So should we set targets and guidelines in terms of resolution time or should we implement formal SLA that are binding?
developers don't have time to fix bugs
Who is prioritising the work? Agile teams often put bugs alongside other development tasks in a backlog. Then they prioritise them, typically by evaluating business value.
For example:
Bug 1 - high value
Requirement 1 - medium value
Bug 2 - medium value
Requirement 2 - low value
The team works on the highest value item first (be they functional requirements or bugs). When the highest value item is completed, they start on the next highest value item and so on.
When new items are added to the backlog their value is evaluated and they are placed in the list at the appropriate point.
No need for an SLA. Just ensure the team is working on the items that deliver the most value.