A service level agreement (SLA) is a written commitment to a customer about the level of service they will receive, usually expressed as maximum response time, maximum resolution time, coverage hours and what happens if you miss.
SLAs are most common in commercial work, where the customer's operations depend on equipment being up. They usually sit inside a broader service contract.
How to measure SLA compliance
Each SLA defines one or more clocks. For each clock:
SLA compliance rate = Jobs that met the target ÷ Jobs covered by the SLA
Say a contract requires on-site response within 4 hours. Last quarter you had 80 calls under that contract and 72 arrived within 4 hours. Compliance is 72 ÷ 80, or 90%.
Define exactly when the clock starts and stops. Common choices are:
- Start: when the call is logged, when it is acknowledged, or when it is confirmed as in scope.
- Stop: technician arrival for response time, or the fix confirmed for resolution time.
- Pauses: waiting on customer access, approval or parts the customer supplies.
Why it matters
An SLA is a capacity commitment written in the language of time. A 4-hour response promise only holds if, at any hour of coverage, a qualified technician can be freed up and can physically reach the site within 4 hours. That depends on how full the board is, how far the trucks are from the site and whether you hold slack for urgent work.
This is where travel enters. A response target fails most often not because no one is available but because the nearest available person is too far away. Checking drive time from each truck's current job, instead of from the shop, is what tells you whether the promise is reachable. The SLA guide walks through setting targets, and emergency call scheduling covers holding room for them.
A common mistake
Writing the SLA before checking your territory. A target that works for sites near the shop can be impossible for sites at the edge of your service territory. Tier the targets by zone or distance if your geography is uneven.
Related terms
- Response time and resolution time are the two clocks most SLAs track.
- Service contract is the agreement an SLA usually belongs to.
- Mean time to repair is a related equipment measure.
Common questions
What is the difference between an SLA and a service contract?
The service contract covers the whole relationship: scope, price, term and visits. The SLA is the part that sets measurable service targets and the remedies for missing them.
What happens when an SLA is missed?
Whatever the agreement says. Common remedies are service credits, fee reductions or the right to terminate after repeated misses. Some SLAs have no penalty and are simply reporting commitments.
Should residential customers get SLAs?
Rarely in a formal sense. Residential customers usually get an arrival window instead. A maintenance plan may promise priority scheduling, which works like a soft SLA.