KeyPoints To get a S Ranking

Would be nice if riot can give a few key points as to how the game judge or decides which champ will get a S rank.

Its very, i mean very easy to get S on supports. But what about other lanes ? Top / Jungle / Mid.

For Adc it should be creep farm or something related to that ?

But what about Mid or Top, Specially Jungle.

It Should not be creep farm for Jungle i hope.

Please Lay down your thoughts.

If a Riot member can spend some time and lay down his thoughts, that would be awesome.