Amazon's process is thorough and I appreciate there are checks and balances along the way. There are multiple interviews, all one-on-one, and usually they include interviewers from other teams with knowledge of the role or skills required. They also have an objective interviewer known as a bar-raiser. So between the phone screen and the interview loop, you'll have anywhere from five to seven one-hour calls (I think). The group then meets to debrief on your interview - they enter their feedback and vote into a system where the other interviewers cannot see it until all have entered, so it takes group think bias out of it. Amazon uses the STAR method interview style.