VERTICAL JUMPS
Just an FYI, and without getting into a whole lot of crap, at most Combines, and particularly with Scout, I think jump pads are used. A jump pad is NOT accurate for big guys. A jump pad favors guys with small feet and good form that allows them to rotate their arms in the air and stay afloat longer. Verticals on jump pads make big guys look like idiots, not because they do not jump as high, but because they do not stay in the air as long (according to the pad) :-)
Nevermind about the not getting into a whole lot of crap, you have officially joined the "I'm sorry I asked club"...
My son also jumped 24" at a Scout Combine (he may have had a sprained ankle when he did it that did not help), but it was on a jump pad. However, when measured at an Addidas Combine and another University's camp where they measured where you could actually touch in the air, he had a 32" vertical. He was measured at various camps and I do not think he ever had below a 28" anywhere that measured where you actually touch in the air. At camps with jump pads, he sucked, every time.
After speaking to a fellow at length one time that seemed to have put all sorts of scientific thought into his argument that big kids with big feet are not properly measured by a jump pad, I wondered why they were ever used. He was one of the guys testing the kids and he told me convenience was the reason; they have so many kids to measure and the jump pad is fast and easy to transport. He went on to say that technique, weight, and foot size, make the machine unreliable because it measures the time you are in the air, not height off the pad. He pointed out that heavier kids do not stay airborn as long, so they should have an adjustment made for relational weight that is not done. Also, he said big feet hurt because the toe of a kid with size 16 feet may still be touching the jump pad when a kid with size 6 feet is 6-8" in the air above the pad, so the big footed kid's jump has not even started yet according to the jump pad, but his heel has moved off the ground exactly the same amount as the size 6 wearing kid. So basically, he said you would have to subtract the difference in the kid's foot lengths to make it fair.
I was so fascinated by this discussion that I actually compared video tape once, and it proved he was correct. By freezing the highest frame, etching a line on the top of their head, and measuring the difference from the top of their head in the standing position to the top of their head at the highest altitude, it proved that 2 players that I think had measured verticals that were 7" or so apart according to the jump pad, jumped the exact same distance into the air.
Wrapping up on this long winded rant, why does a vertical even matter in football, I want to know what the highest point in the air is that you can freakin touch, period! People are assembled so differently as far as arm length, shoulder height, etc.; that one kid that is 6'1" like Amari can stand on his tip toes and touch something 8'4" above the ground, while another can only reach 7'6" due to shorter arms, lower shoulders. etc. For this reason, I would think coaches would want to know what the highest freakin point is that they can touch when jumping into the air, and if we must have a score, lets just subtract their true measured height from this number...
This takes all the cheating techniques, weight factors, and shoe sizes out of the equation...
PS: Final puff of wind, I do not think that coaches care much about combine results, they seem to care more about what they see in person and on game film...