To start, I think there are useful metrics which may be used during testing. Used incorrectly, the metrics are often misleading. The story goes like this. There are two testers who happen to (beyond all probability) find 5 identical defects in a product. The first logs all products in the issue tracking tool and forgets about them. The second brings the defects directly to the rest of the design team and talks about them. While communicating, his team determined that 2 of the defects were actually working as designed and the tester had misinterpreted the requirement. Another 2 defects were quickly fixed and required no issue, the programmer fixed the issues before the meeting was even finished. The last was an issue which the tester logged.
So who is the better tester? The one with 5 issues, or the one with 1?
With that kind of story in mind, my teams tend to use, among other tools, a different indication about the success of the sprint/release. How do we feel about our progress? Do the testers feel that we have done good testing? Do the designers and programmers and architects feel like we have communicated our results effectively? Does the management have faith in our reported results? Have our customers given feedback?
These are (mostly) not measurable, thus we talk about the product and the processes instead. The team does this in the sprint retrospectives. The management does this through my constantly asking for feedback. The customers do this through buying more of what we are making. While emotions are often just as misleading as metrics, the chance is good (in my experience) that if the team has a positive view about what the testers are doing, then testing is proceeding well.
Now, there are huge requirements for tracking by emotion to be an effective tool. If nobody is actually looking at the tests, then it’s easy to make the tests look deep while, in fact, they are shallow. Thus team members should involve themselves in processes which aren’t traditionally their own.
I will cut this off by saying that there are very clear disadvantages to using only emotional indicators (which I would be happy to discuss further), but given that I take the line “Individuals and interactions over processes and tools” to heart, I feel that at least discussing the merits and pitfalls is worth the time.