"People who don't use wards lose X% more games."

yeah but that actually require effort, lets just say its common knowledge that if you don't have map awareness, your going to die alot, hence losing/

thatd be hard to find out since everyone uses there free trinket. finding out how many times its been used depending on the player for every league game would be tough.

but i do see your point.

even with trinkets people dont buy wards to help the map vision, its just how ppl are.

honestly im guilty of that too.(unless im support)

I think it's a bad statement altogether because honestly at higher ELOs the main reason people don't buy wards is due to being behind. You're getting crushed early in mid lane and back with 835g most people would buy double doran + a pot or a doran + amp tome. If you were winning lane and backed for the first time with 1000g you would get your chalice, some pots and a wards since you had money to spare.

The point is most times the team with fewer wards placed/bought are already behind in the first place and are trying to catch back up in lane and not spend the extra money on wards.

I mean honestly in the first situation where you're losing lane and back with 835g how many of you would really buy doran + boots, ward and a pot over the other two options?

Firstly, that statistic would basically be "Win rate of laners who buy wards+Supports+Sighstone Junglers," and "Win rate of laners who don't buy wards+ADCs." Different roles have different duties when it comes to the vision game, so unless you're boiling it down to something as basic as "Lee Sin Jungle players who don't buy wards lose X% more games," you're not actually giving relevant information to the person reading it. Compare to raging, which has an identical effect no matter who's doing it and what role they're playing.

Secondly, if you're playing at bronze Elo where nobody buys a single ward and the support doesn't even use the sighstone they rush, "players who don't use wards" is going to be every single player, and their win rate is necessarily going to be 50%.

Also, if someone's keeping their yellow trinket all game because they don't understand how contesting vision works and they just drop it on CD in inefficient spots, their win rate is going to look like the win rate of somebody using wards, but will actually reflect the win rate of someone who doesn't contribute to the vision game.

So, without further context, the statistic is pretty useless.