Talking is such an incredibly valuable thing. Whether it's in person, by phone, over IM, or even email, having a conversation can tell you so much more than looking at a piece of documentation ever will. As a tester, if I can get a quick overview of the feature from the development team, I can quickly learn how buggy that feature is going to be - just from how they talk about it. As a developer, when the product manager explains a feature to me, you can hear in his words whether it's well thought through or if I should plan some extra time for rethinking and reworking and integration. I think most of us get those kinds of senses over time.
But how do we know?
Some phrases and actions indicate confidence, and other indicate a lack of confidence. So when a product manager talks about a feature with confidence, he's probably thought through it. When a developer talks about a feature with a lack of confidence, then there's a hole there: edge cases, poor integration, something.
Indicators vary by person, and take some time to learn for each person. However, there are some common ones:
- Direct, relatively short answers
- "Sure" or "No problem" in answer to a question
Lack of confidence indicators:
- Hand waving (yes, actual literal hand waving!)
- Repetition of previous results
- Asserting something works without describing how it works
Sometimes it seems like there just isn't time to stop and have a conversation at a transition point. But take the 10 minutes and have the conversation. It's a rich source of information..... as long as you use it.