Effectiveness is in non-repeat of what raised the nonconformance, but we also track responsiveness to the request for CA, time to fix, and time to close.
We found that one good way to shorten response time and improve the energy level was to adopt a cooperative approach. I now send out drafts of my audit reports and ask if everything is correct. We also have meetings in the more complex cases, where the recipients will need to have awareness raised, where resources are needed, and/or where responsibilities are unclear/shared.