Change failure rate
The share of deployments that cause an incident, a rollback, or a hotfix. Vendors do not all use the same numerator, so compare a tool to itself over time before you compare two tools.
Why it matters to an engineering manager
This is the check on deployment frequency. If the rate climbs while you ship more often, the system is absorbing risk it used to batch.
Which tools measure this
Tools tagged DORA. A tag means the vendor's pages listed it. It does not mean every sub-metric is broken out.