The level of "5 why's" depends on the level of the person doing it, going as far as its needed to reach that level where you should be driving change. In the "

The level of "5 why's" depends on the level of the person doing it, going as far as its needed to reach that level where you should be driving change. In the "car won't start" example of the original article, the motor pool mechanic needs to stop the whys at the broken alternator belt, because that is something they can and should fix; the motor pool manager needs to go on until reaching the practice/policy for how often preventive maintenance is done, and the top management (if the consequences are severe enough to warrant attention) need to go on until the "why do we have poor car maintenance" questions reach things like mid-management forcing people to ignore the maintenance schedules, or staffing policy, budget for whole departments, and/or the choice to outsource/insource that function. But going on much further than your own level is not going to be productive - you can make an actionable suggestion to your boss if some root cause isn't fixable at your level but is fixable there, and that's about it, at least in my experience.