talks about the benefit that formal checklists can have in giving support team members the ability to speak up when something on the checklist is missed by the person in charge (that's not the only purpose for the checklists but it is one of them). Operating rooms and commercial airline cockpits are two places where such checklists have been introduced. Both are places where it has been difficult for some underlings to speak up when the surgeon/pilot doesn't do something correctly or misses key safety steps.