This was my first thought (that the effect is just due to correlation with people already being unhappy with their current position, rather than specifically being caused by the rejection) but the article says this which seems to potentially suggest otherwise:
> Second, a rejected candidate’s likelihood of leaving was cut in half if they were passed over in favor of an internal candidate, rather than an external candidate.
That is surprising to me. I'd expect that your peer getting a promotion over you drives a lot more people to leave than someone external being hired for that position.
Psychologically, I think I understand. Selecting a peer over you means they were slightly more qualified than you, it could happen to anybody. Selecting an outsider means you weren't even remotely considered. And if they aren't seeing you and your contributions maybe another organization might.
I can understand this. The last time I didn't get a promotion, I saw the coworker that got it and thought, "Yeah, that makes sense, she's great for that role and more experienced than I am." I didn't feel slighted the same way I may have been if it were someone completely new.
> Second, a rejected candidate’s likelihood of leaving was cut in half if they were passed over in favor of an internal candidate, rather than an external candidate.