A Service Level Agreement, or SLA, is a stated commitment about the level of service that will be provided, expressed in terms both sides can measure — most commonly how quickly a request will be responded to and resolved.
Response and resolution are different promises
Response time is how long until someone picks the ticket up. Resolution time is how long until the problem is fixed. Conflating them is the most common source of disagreement about whether an SLA was met.
The clock is the hard part
Most SLA disputes are about time, not effort. Does the clock run overnight, at weekends, on public holidays? Does it pause while waiting for the customer to reply? Two systems measuring the same tickets under different pause rules will report different compliance and both will believe they are right.
Priority and escalation
SLAs are normally tiered by priority, with escalation when a target is at risk rather than after it has been missed. An escalation that fires only after breach is a reporting mechanism, not a management one.
