This is a ranking of the current skill level of each player on the list. Some players may not have logged on in a bit but their rankings represent where they would stand if they played a game today. I've played and won ESL tournaments, ToLs, ToGs, Mistpedias, and so many other tournaments throughout my "career" as a competitive GW2 player under the name "Backpack". While this list is posted by me, it has almost none of my input, the rankings were formulated by consulting with over 15 top players from the current top NA competitive teams in addition to reviewing footage from recent monthlies, and the Mist tournament, and UGOs before their break. While I only play the game casually now and am probably a bronze tier player at this point I can still view todays competition in a "balanced light."
Mechanical skill incorporates decision making (stomping, cleaving, targeting), interrupting key skills, 1v1 abilities, tracking cool downs, understanding every classes abilities and vulnerabilities, dodging, staying alive outnumbered, etc. Conquest skill incorporates map awareness, being able to use terrain, understanding rotations, openers, counter rotations, knowing each classes role in conquest, communication, stalling, regrouping, etc. The rankings which can range from 0-100 represent the overall combined value that they would bring to a team. With 100 meaning that player is as valuable to a team as anyone else at that rating and more valuable than everyone below their rating. A rank of "20" doesn't mean this player is in the 20% of the game, it simply is relative to the top where skill scales exponentially. A "20" on this list is a better player than 99% of the pvp population.