The classic seven quality tools and the seven management tools are not the only quality tools available to a root cause investigator. Other quality tools may be of great use in assisting a root cause investigator. One simple concept that should be used during any root cause analysis is asking “why” five times. Without asking why more than once, there is a danger that the root cause that has been identified is a contributor to the failure under investigation, but not the true underlying root cause. This could lead to misdirected corrective actions and a recurrence of the failure.