Higher ups in the company having input on who is selected for hiring. During our Delta interview, it was stressed to us that it didn't matter who recommended us, the scores that had earned us the invite to interview were based on our application, not our recommendations. We found out later that one of the guys had a recommendation from the CEO, and another had one from a senior VP. The only discriminator that seemed to make a difference was doing interview prep. The ones who skipped that failed their interviews and didn't get hired.