I was wondering just how important attending a combine is for a recruit in terms of his star ranking. Can most top recruits be expected to attend a combine?
If you're talking about the camps, then extremely important. Other than film which can be sent direct to a coach, camps are one if not the primary way that players earn a star ranking and attention. Scout, Rivals, and Nike are the big time camps and there are lots of others. Many are regional to increase the likelihood that more players will attend. And yes, most top recruits attend at least ONE camp. There are exceptions if they've garnered early media attention like Jimmy Claussen. He skipped camps last year including the Elite7 QB camp. Not a judgement on him, just a fact. You have to keep in mind too that once a player camps and catches the eye of a top 10 program, the offers they get from those schools can also boost their rankings. Most of the ratings services only calibrate their rankings a few times during the season so it's definitely not fluid. Unfortunately, lots of terrific players can't afford to attend camps nor put together hi-tech game films and can easily get overlooked. I've seen their coaches or family members even come on forums like this to ask for help or beg someone to look at their kid.
Going to a school's camp can greatly influence whether a recruit gets offered by that school or not. Going to other recruiting camps help them get noticed, and are definitely a factor in a recruit's rankings. Many times recruiting services won't have seen a player at all except in camp - especially in areas like rural Louisiana where the schools aren't good about getting tape out.
A guy I work with has a son that will be a junior next year. He plays safety/receiver. He really had a nice growth spurt this year. He is now about 6'2" 175. A couple other kids on his team were already being recruited, and the recruiters came by there spring practice to check in. They saw his boy and told him to get his butt to every camp you can. Right now nobody knows about the kid, he started all last year, but was about 3 inches shorter. Anyway, he was basically told get in the camps and impress them with your size and speed before the season starts. Then they will all watch you all year long. His coach called the guy I work with and basically told him that over night his son could go from just another decent HS player to a top tier recruit, if he gets to some of these camps because of his measurments. So I would say the recruiters obviously think the camps are very important.