Should I pay attention to it? I feel it does not reflect performance many times. Like last game with Hecarim jg we won at 20 minutes surrender 9v1 and I was jungling. I was the only death but I did a countergank that resulted in a double kill for a top laner and started a fight that aced the team and got us dragon. Yet I got a C??
Without seeing your game, I can't really explain how you got a C other than saying that KDA and getting a dragon are small pieces of the grading system. Warding is also a huge part of it. The grading system takes into consideration what champion you're playing, the role, and what you did compared to other players in your region. It's hard for me to tell you exactly what all goes into the grading system other than what popular opinion is and assumptions, but you asked, so I did my best to answer. :)
http://na.leagueoflegends.com/en/page/features/champion-mastery
EDIT: All-in-all, yes. I'd say you should pay attention to it.
you should not pay attention to it... we dont know the grading criteria, so you dont know what you are comparing against.... it has seemed to people through anecdotal evidence that to get some of the higher scores the game has to go longer for instance.... that imo has little to do with your mastery of the champion... play for fun and you will have a better time
It seems to use some combination of CS, Kills/Deaths, % of fights your champ is involved in, and some kind of "lane win" component (maybe turrets?). It also over-weights winning or losing, in that getting a high grade with a loss is very difficult even if you play exceptionally well, and you can get Bs or sometimes even As while being carried. League points and MMR/ELO are already there to evaluate team performance + individual performance over time. These grades should better represent a score for how an individual contributed to a single game. Being the only player to go positive on the team in a 4v5 with an afk and doing something like 9/3/7 while literally everyone else on the team that didn't AFK was negative and lost lane is not a situation where you deserve a "B" grade; what more could you have realistically done? Over time enough games will iron out the noise that puts on MMR, but for individual game performance grades they'd be more useful if they more consistently represented performance in that individual game.
I wouldn't put much stock in it for now. It's a good concept that doesn't seem fleshed out yet. I have been going over some of my games lately and I've had a few games in the A+ to S range where I made more significant mistakes than games where I got a B or less, simply because we wound up winning or the other team threw even worse. To me, if it's working like it should be, that kind of grade disparity should be very rare.
Eh, Its ok. It needs to be an infinite ranking though. IDC if the symbols change but I want to be able to say, "I'm a level 76 Gnar."
