Proof that Santa is a tenured senior faculty member at a university:

1. You never actually see Santa, only his "assistants."
2. Santa keeps his job until he decides to retire.
3. Santa doesn't really do the work; he directs a bunch of helpers to do all his work for him, but he's the one who everybody credits with the work.
4. Santa doesn't work anywhere near a 40 hour week.
5. Santa travels a lot.