DE Mario Edwards head of class

As we began to research and pool together the top 300 prospects out of the 1,500 we have evaluated and graded for the 2012 class, it became more and more clear this is a top-heavy class with prospects that began to separate from the pack.

However, you also will see we have more grade 80 prospects in the 2012 ESPNU 150 than ever, which indicates the difficult choices made to fill out the rest of the list. In fact, the process of molding this group was similar to the 2010 class, where there could be much more movement in the top 10. There was no obvious choice for the top spot like there was last year with defensive end Jadeveon Clowney.

A defensive lineman tops the ESPNU 150 for the third year in a row. Defensive end Mario Edwards of Denton (Texas) Ryan is No. 1.

As is usually the case, our top 10 is half full with either offensive or defensive linemen. There were certainly enough difference-makers at multiple positions to round out the top 50 fairly clearly in our opinion. However, around No. 51 in the country down to the low 80s is where our grades dipped lower than what we have seen in the past.

There are 30 defensive line prospects, which is slightly down from years past, and 21 offensive tackles, but in our opinion there is not a Christian Westerman or Cyrus Kouandjio in this group. Our No. 2 player, defensive tackle Eddie Goldman of Washington (D.C.) Collegiate Academy, narrowly edged out some talented prospects in the top five. Offensive tackle D.J. Humphries of Charlotte (N.C.) Mallard Creek is a wonderfully gifted player who has huge upside technically, yet his best football is ahead of him.

For the second year in a row we have two running backs in the top 10. They are Keith Marshall of Raleigh (N.C.) Millbrook and Johnathan Gray of Aledo, Texas. Marshall is more of your big-play threat, and Gray is more of a power load carrier. Marshall is not as strong, and Gray is not as fluid.

As we always say, there are no perfect players. Everyone has weaknesses. The question is, are those weaknesses visible as a player or do they manifest themselves down the road in other areas? That is what makes high school player evaluation such an inexact science.

There are certainly a lot of wide receivers (19) in the ESPNU 150 because there are a ton to choose from. There are not as many definitive difference-makers near the top. Surprisingly, we also have 19 athlete prospects, which is a rather large number, but instead of moving them into another position, this group of athletes are either playing quarterback in the spread or playing multiple positions. Without seeing significant reps at one position, we felt it was necessary to keep them as athletes.

Not all of the athletes are "skill" guys, either. Jabari Ruffin of Downey, Calif., should become an outside linebacker. Beniquez Brown of Florence, Ala., could end up as a linebacker, running back or safety. Jeremy Liggins of Oxford (Miss.) Lafayette probably will be a defensive lineman.

We kept Stefon Diggs of Olney (Md.) Our Lady of Good Counsel atop the athlete category because the more we watched him the more positions he played. While many feel he will end up as a wide receiver, we would not be surprised to see him on defense. His lack of top-end speed is what kept him from receiving a fifth star at this point, but he is right on the cusp.

Recent Auburn commit Ricardo Louis of Miami Beach Senior may have made the biggest jump up our board of any prospect in the category. Regardless of where he plays, he is a big play waiting to happen, and he is not a little guy.

The Process
While each member of the scouting staff is responsible for a specific number of graded prospects each week during the spring leading up to this point, our process is perhaps more unique than you might think. First, no member of our staff is regionally based in his evaluation efforts. Our staff is assigned to evaluate positions they have played, coached or scouted through years of experience, regardless of which region the prospect is from.

You may be asking why that is. Well, it's quite simple. Every evaluator is responsible for his positions regardless of state or region. He then will see all the states, all the regions, all the schools, every level of competition and be able fairly and objectively to make assessments and comparative analysis of a single position because he has seen everybody with no area bias. Then, we as a staff will scrutinize it all over again, only this time with multiple sets of eyes on each prospect, and begin to finalize each prospect at his position, for every position.

The most important part of this process is that regional bias is eliminated. There are no instances where the Midwest scout believes he has the best DT in the class and the West scout wants to arm-wrestle him on behalf of his top DT prospect even though neither has seen the other player.

The goal is to try to make an inexact science as exact as possible given the information we know going in. Are we going to be right all the time? Nope, and we don't pretend to be.

The key is going with your gut, what you know and see regardless of hype. Perhaps most importantly you can't be afraid to be wrong because you are going to be and so is every college coach in America. It is part of the process. Do what you can in your evaluation efforts to narrow the margin of error.

As we have always stated, there is a premium placed on five positions when it comes to rankings -- quarterback, offensive tackle, defensive tackle, defensive end and cornerback, all of which are the most coveted at any level of football. Unfortunately, QB, OT and CB are the most difficult to evaluate and project, especially at the high school level.

There are going to be occasions in every class where a great player at another position trumps a good player at a premium position. Receivers Dorial Green-Beckham of Springfield (Mo.) Hillcrest and Eddie Williams of Panama City (Fla.) Arnold are prime examples in this class, as were 2008 class receivers A.J. Green and Julio Jones. Rare players at the wide receiver position are the easiest to find year in and year out.

Film study is the foundation of our work, along with in-person game evaluation. Camp and combine assessments are purely a supplement to what we see on tape. The importance of game film, multiple games and most notably non-highlight plays is going to give you the most well-rounded assessment to help differentiate between hype and production.

Average or below-average plays from highly exposed prospects are going to come up, and deciding what is coachable and what is not, and what you put stock into, is going to have a dramatic effect on our rankings. Regardless of ability level, if a prospect does not play hard, is stiff or lacks toughness, it will say a lot, even when you know he is gifted.

As with every class, this is a fluid process of rankings, at each position and within the ESPNU 150. Over the summer you may see some movement, and certainly through the fall and winter leading up to February there will be more. By February we will have around 3,000 player evaluations and the BCS conference school classes rounded out.

Until then, debate, argue, be happy, be sad. And of course we expect some anger, too. It goes with the territory.

Tom Luginbill is ESPN's national director of football recruiting.