Wherry organizes her thoughts on managerial mistakes by documenting problems at different levels of an organization's management hierarchy. Here, for example, is the hierarchy at Meebo, along with a few words of advice from Wherry:

Individual code writer $("$Don$\text{'}$t turn down anyone offering help"$)$

Manager $("$Stop trying to do your old job"$)$

Director $("$Don$\text{'}$t promote someone and then disappear"$)$

Vice president $("$Don$\text{'}$t reverse a plan midstream"$)$

CEO $("$Never let your guard down"$)$

How is this level$-$by$-$level approach reflected in the kinds of mistakes that Wherry identifies? Why is this approach effective in identifying mistakes? How can it be effective in avoiding mistakes?