Keeping score in a team game with defined roles like this is VERY toxic, ESPECIALLY in solo Q. It actually hurts intelligent gameplay, and is counter intuitive (something which riot is against, barrier to learning I think is their term, where something is too hard to understand for beginning players).
More often then not, people not only chase kills, but also say "hey look i'm not doing bad as [insert random tank support here] because I never died, AND I have the most kills"
Here is a PSA: as a tank or a support you should IDEALLY die more than other lanes for the following reasons :
1. Tanks are supposed to (for the most part) intiate, meaning you will be going in first, and taking damage Not dying is counter productive in a sense, as a tank, since it is your job to...come close to dying (ideally not die, but in a completely "balanced game" 3-4 of your own team members should die after the first team fight, since everyone is playing optimally. I understand this is not how the game works, especially in solo Q or with certain team comps, but just speaking theoretically in an even skilled game, both teams should be scoring kills in team fights).
2. Supports are supposed to have the least items. It doesn't make sense for a support to take lane gold, in an IDEAL game (note that I do take gold as a support, in order to carry bad team members). However, ideally supports should have LESS gold than other members of the team, hence they will have less stats. In general, they should be the EASIEST member of the team to kill.
Too often I see people using score as a means to justify their horribly inefficient play. "If I sit back and KS as x support or HP building tank, im helping my team!!" no, you are just trying to get a good score. Honestly, this is one of the things heros of the storm did right. KDA should not be shown in solo Q untill the match is over.
I am sure there are less toxic stats which can be recorded during the game, which help players learn how to win games, and not just show off or try to boost their own egos in solo Q
In my opinion, killing sprees, penta kills, double kills ETC all serve to give people a false sense of playing well as well. It encourages people to chase kills they probably otherwise shouldnt, which can lead to the other 4 smart players on the team possibly losing the game.
I realize that riot runs on making the game as addicting as possible in order to maximize profits, however, I believe the long term health of the game will be stronger if this issue is addressed, and I believe that it is actually in riot's best interest to not show KDA in ranked solo Q. Leave it in normals and team ranked, thank you.
Please remove KDA in game, and display it only on the end game score screen.