PG's talent/potential rating system is to baseball talent/potential evaluation what the military justice system is to justice (or military music is to music). We are talking about "rough" justice, rough music, and rough evaluations.
Two sixty times at 0800. Six ground ball plays. Ten swings against BP pitching. Two games, maybe 5 or 6 at-bats and 5 or 6 fielding chances. Seriously, how much is there to evaluate?
I have to believe that PG looks at the 60 time and throwing velocity most, since those are the only two objective measures in the evaluation. Based upon the athleticism reflected by those two numbers, PG can project POTENTIAL. The kid who is a 6.50 sixty guy and who throws 88 mph across the infield projects, wrt POTENTIAL, better than the kid who is a 7.10 sixty guy and who throws 78 mph across the infield. The former gets a 9.0, the latter a 7.0. PG will admit, I think, that those numbers do not, indeed, cannot, reflect heart, work ethic, attitude, skill (vs. athletic talent), or even quickness, hand-eye coordination, knowledge of the strike zone, game understanding. . .
So, the 7.0 kid may end up being a much better player than the 9.0 kid, above, because he is single-mindedly committed to getting better and doing what is necessary to play at the highest level possible. The 9.0 kid may not care, may be lazy, may not work hard at all. Who knows.
PG's projections, then, are rough, at best. I don't think PG denies this.
It would appear, from what I have observed and from the discussion here, that PG may want to tweak the numbers a little. Using metrics from their database of profiles, PG should be able to reveal how many of their 7.0s ended up in the pros, or at Div I, and so forth. Same for all levels.
But the PG score is only one rating among many. What counts, in the end, is the fit for the kid and whether the coach and staff at a potential college think the kid fits in the program. The fit should be comfortable both ways.
I have written on this site before, and will repeat it here--baseball truly does reflect life. The top 10% are clearly superior, whether it is baseball or military performance or med school or sales. The bottom 10% are clearly there for a reason. It is the middle 80% that provides the challenge. How do we distinguish among this group? My guess is that at any PG event, or like event, the top 10% score 9.5 or 10, and they clearly are superior baseball talents with superior athletic potential. They are bigger, faster, stronger. The bottom 10% tend to stay away from PG events, but still, you get rankings in the 5/6 range. These young men should not give up, but they should refocus on getting better and finding a great college fit. Those ranked 7 to 9 are in the crunch. I suspect alot of 7s are as good, in the end, as most of the 9s. The athletic potential that PG is able to measure in the limited opportunity to see them is awfully close. Those who succeed (say, play Div I ball) are those that have the best work ethic (heart, attitude, dedication) and most opportunity (you cannot get better if you don't play).
I know of two kids at the HS my son attends. These two scored 7s at PG events. Both are playing major Div I baseball. The work ethic and skill level these kids developed allowed them to simply surpass the "better" athletes (some of which were almost certainly graded well above them at the PG events they attended).