[Mick]

- the overall level of randomness of the whole process?

That's what I'd pick. On average you'd expect more highly regarded recruits to be more highly regarded players in college and the NFL, but that's going to require a lot of averaging given the inherent uncertainty and randomness involved.

In fact, I think the role of randomness in outcomes in sports is wildly underappreciated, as in the classic XKCD:

Agreed. The same can be said for college admissions in general. Kids from all over the country face different levels of difficulty, have different teachers, come from different home environments with different levels of access to resources, exhibit different levels of resilience when faced with greater challenges, and develop at different rates. To top it off, once you reach a certain level of observed performance, they’re all really good and it’s hard to draw reliable distinctions.  

But hey, I went to a “safety school” (sarcasm) because Stanford declined me 28 years ago, so I might have a small chip on my shoulder. ;-) For whatever it’s worth, I declined Cal.

A good friend of mine was a 4.0 at SCU (difficult because the average back then was a 2.68) and received offers from seven of the Big Eight.  In his final interview with Ernst & Whinney, the OMP of the SJ office asked him "What did you find different from what you had expected about college?"  His reply?  "Grades are completely meaningless."  The OMP, as credentialistic as any lawyer sputtered "How can you say that?  You have a 4.0?"

My friend touched on all the variables you mentioned; e.g., different teachers and different grading systems, whether one had a second job or a sport, the grading differences between majors, etc.

[Mick]

- the overall level of randomness of the whole process?

That's what I'd pick. On average you'd expect more highly regarded recruits to be more highly regarded players in college and the NFL, but that's going to require a lot of averaging given the inherent uncertainty and randomness involved.

In fact, I think the role of randomness in outcomes in sports is wildly underappreciated, as in the classic XKCD:

Agreed. The same can be said for college admissions in general. Kids from all over the country face different levels of difficulty, have different teachers, come from different home environments with different levels of access to resources, exhibit different levels of resilience when faced with greater challenges, and develop at different rates. To top it off, once you reach a certain level of observed performance, they’re all really good and it’s hard to draw reliable distinctions.  

But hey, I went to a “safety school” (sarcasm) because Stanford declined me 28 years ago, so I might have a small chip on my shoulder. ;-) For whatever it’s worth, I declined Cal.

A good friend of mine was a 4.0 at SCU (difficult because the average back then was a 2.68) and received offers from seven of the Big Eight.  In his final interview with Ernst & Whinney, the OMP of the SJ office asked him "What did you find different from what you had expected about college?"  His reply?  "Grades are completely meaningless."  The OMP, as credentialistic as any lawyer sputtered "How can you say that?  You have a 4.0?"

My friend touched on all the variables you mentioned; e.g., different teachers and different grading systems, whether one had a second job or a sport, the grading differences between majors, etc.