Board Thread:General Discussion/@comment-1312012-20161212132314/@comment-1038387-20161212141646

Not for all of them. In most cases, there's a fluid transition. If there is a cut-off, it's often arbitrary - a new origin, a new look, that kind of thing. In many cases, that happened before Barry Allen's debut.

I wouldn't say "a wiki editor" decided this - this has been a point of contention for so many years that many people decided it long ago.