[brownkonas]

I have used it to success, but you have to allow for multiple answers to be given at each level that create their own branches of a tree. Which is effectively what the author illustrates as completely different outcomes. The group should make an effort to give multiple reasons in each iteration and follow them each separately.

5 Whys's also needs to be preceded by a detailed representation of what happened and followed by multiple next actions that are tracked to completion.