Definition
Resolution rate is the share of customer contacts in which the customer's problem was actually solved, whether by an automated system, a human or both. It is an outcome measure, so it needs evidence beyond the call ending.
How resolution rate works
Resolution rate = contacts where the problem was solved / total contacts x 100
The difficulty is proving “solved”. A call ending is not evidence, and neither is an agent saying “all done”. There are three ways to check, from strongest to weakest:
- A record in the system that owns the outcome, such as a changed appointment, an issued refund or a closed ticket.
- The customer’s answer to a survey question, or the absence of a repeat contact in a window.
- A judgement of the transcript, by a person or by an LLM that is asked a fixed question.
Each has gaps. The system record shows the action happened but not that it was the right one. Silence from the customer can mean the problem was solved or that they gave up. A transcript judge can be wrong, so someone should read a sample of its verdicts against the real outcome.
Resolution is a different question from the nearby metrics. Containment asks whether a person was involved. Deflection asks whether the contact entered the queue. First call resolution asks whether it was solved the first time. Resolution rate counts the final result regardless of who produced it or how many attempts it took.
Why it matters for voice agents
A voice agent can keep a caller talking and still fail them, so call outcome is the number to hold to account. The contact center automation guide recommends verified resolution over containment for this reason.
Cartesia’s Managed Agents score every completed call with built-in metrics, including call success. Check the metric’s definition before treating it as resolution, because a call can end cleanly and leave the problem open. A custom metric, defined as a question to an LLM judge such as whether the caller’s issue was resolved, comes closer. The docs advise testing it on real transcripts before relying on it.
Example
An illustrative sample of 200 calls about order changes (invented numbers): the order system shows 150 changed as requested, 20 callers were transferred and a person completed the change, and 30 calls ended with no change on record.
Resolution rate is (150 + 20) / 200 = 85%. Containment on the same calls is 180 / 200 = 90%, which overstates the result by counting the 30 failures.