Change failure rate
A key metric when making changes to systems is what percentage of changes to production (including, for example, software releases and infrastructure configuration changes) fail. In the context of Lean, this is the same as percent complete and accurate for the product delivery process, and is a key quality metric. — Accelerate: The Science of Lean Software and DevOps. IT Revolution Press
Change failure rate, or CFR, is total number of deployments in failure state during any given period over the total number of releases deployed during this period. It is computed using the declared deployments and their statuses.