Agreed. I think some people must take the "5" portion very literally, but that's never how I've done it. I just recently did a 5 whys session on some productio

Agreed. I think some people must take the "5" portion very literally, but that's never how I've done it. I just recently did a 5 whys session on some production data loss. We ended up with a branching tree that had 22 items and was up to 6 items deep. In the past I've ended up with bigger and deeper ones. To me, the "5" is just a reminder to really dig. For me it's also a practice that's most valuable when used frequently. As you see similar things crop up in different sessions, that's a great sign to dig deeper. E.g., one of the leaf nodes in our recent retro was "no official process". That's deep enough for us; we'll create an agreed process for this particular thing and put it in the wiki. But if I see that a couple more times, I'll definitely drive the cause analysis deeper.