A stat that measures how good a certain player is versus his competition. Consider it kind of like a number rank like halo 3 used to be except more specific. So halo 3 was 1-50. Elo is like 800-2700. When you are in trials and matched with a team the average elos are calculated for each squad which provides a likelihood/percentage of which team will win. So a 1200 average elo team should win vs a 1000 elo average team. If the 1200 avg elo team wins their elo goes up very little since, by percentage, they shouldve won. If the 1000 avg elo team wins their elo will go up quite a bit since they were the underdog. Which is where carrying players now comes into play. If 3 super PVP gods play together and their elo for their team averages to basically 2000 they are essentially supposed to win against every team they face. (You dont normally come across a 2000 avg elo squad itd be like facing 3 level 50s in Halo 3 at the same time) So if that squad loses their elo will drop quite a bit every time. So thats why those twitch streamers are so happy to help the common man. Sure it generates views and is a nice thing to do but it also has a selfish element to it. If the 2000 elo god and his 2000 elo buddy add a 900 elo scrub player that teams average elo now drops to about 1650 instead of that 2000 average. In trials having 2 out of 3 great players can usually overcome 3 decent players so now if the twitch streamer beats a team whose avg elo is 1700 their own elo will jump quite a bit even though their individual elo is well over that 1700 number. Then double carrying comes in where if a 2000 elo carries 2 scrublet 900 elos the teams avg elo now becomes less than a 1300 avg. The majority of teams past Id say win 6 are above the 1300 avg elo range. That means the 2000 elo carrying two kids to flawless is getting a massive elo boost after win 6-9 and if the streamer loses their elo barely drops. Its a low risk high reward situation. The fact that ELO matters to people is silly because as you can see by what I wrote it can be easily manipulated. Its kind of a cool stat to show where you stand in a way but its certainly not the end-all be all statistic that players should use.