It's not easy to tell when bias shows up. Collage rankings might look like an unbiased formula, but it's selected so the 'top' schools end up being highly ranked instead of measuring useful things. Things like a high faculty to student ratio don't actually directly have much impact but it's the kind of stat easily gamed by 'top' schools so it's gotten some sort of mythic importance even if these people don't actually teach undergrad classes.

You can find the same inherent bias in many walks of life. Many of the hurtles to becoming a Doctor have nothing to do with being a good Doctor there just there to ensure the right kinds of people get into and out of the program.