We shouldn't underestimate the value of feel good metrics, though. Feeling good is important :-) I like to measure code coverage for changed code within a roll

We shouldn't underestimate the value of feel good metrics, though. Feeling good is important :-) I like to measure code coverage for changed code within a rolling time window, say 6 months. If people are writing tests for all they change, you rapidly get close to 100%. This gets past the issue that in many large code bases, you could probably write tests for ten years straight, end up writing lots of tests for code that doesn't change, and still not get close to 100%.