An important thing to realize is that no matter how much they try, a company the size and profile of Google has at best only a loose control over their hiring p

An important thing to realize is that no matter how much they try, a company the size and profile of Google has at best only a loose control over their hiring process. There are too many internal recruiters of varying ability and agendas, and too many interviewers of varying ability and agendas. A company like Google can have stated hiring principles and techniques, but in practice it's going to be nearly random.