This is not an exact science - when some people say how did player "X" not make the team it is because they have seen what a great player he has been for as long as they have been watching him and it has nothing to do with how he performed at a short tryout and when an evaluator did or did not see him
I think the politics comes in to play when they select the team and maybe a great player had an average tryout and his high school coach politics for him because he knows the kid is great but if that HS coach was not in the room he is not there to politic.
Last year a 2015 kid was cut from the team yet signed with Hopkins three weeks later. maybe Hopkins is wrong or maybe they have seen more of the body of work and like the kid. It does not mean the evaluators are stupid for not taking him maybe he just had a bad tryout. it is not always a conspiracy. In 10th grade Michael Jordon was cut from his HS basketball team and played JV while another 10th grader played varsity, it worked out OK for MJ | 
