Here is some of the hiring/interview criteria I have witnessed over the years ...

- This person lives too far away - the address was on the other side of town
- This resume is neat and short,  call this person.
- Call the top five resumes in the stack (they were not reviewed) for an interview
- We have too many people from this school, call someone else.
- We need to make this interview fair, call this external person but we won't hire them
- And the opposite, call these external candidates for an interview and pick one internal candidate
- And my personal favorite,  we already have a Fred here we can't hire this guy

Yes there's bias in hiring; especially when you get too many resumes, you have zero time and you haven't got a clue about hiring or interviewing.