What is the difference between ELO and True Skill 2

Originally posted by MazrimReddit

this thread and some twitter hysteria is based on this riot post

https://old.reddit.com/r/leagueoflegends/comments/18tv4gb/it_feels_really_awful_to_achieve_your_highest/kfy0rat/

I read it as probably only looking to help with placing smurfs quicker primarily but can you confirm if any major changes like using KDA for LP are in any way planned

Originally posted by Affectionate_Car7098

Nothing about TrueSkill2 implies that we must use or weight any additional factors outside of win or loss.

Oh thank god a voice of sanity, not that people will read your message they will just whine that the system favours ingame actions, which afaik, it does not currently do anyway

But then again after 13 seasons people still think losers queue is a thing so while i greatly appreciate your post, as do many others, i suspect many people will not read it >.<

Originally posted by Huzzl3

Hey, I have some questions regarding this, feel free to clarify if I'm wrong somewhere, I don't do this for a living:

Problem statement
Obviously, the goal of LoL is to win the game, and whether you achieved the goal is measured by exactly that: Win or defeat at the end of the game. Of course, different players will contribute different amounts to the outcome of a game: A 15/5 vayne likely contributed more to the win than the 0/13 warmogs rush yuumi top, or in case of a defeat, the 0/13 yuumi top likely contributed more to the loss than the 15/5 Vayne.

It would be great to quantify everyone's skill level in a game based on their performance, so that better players gain more LP (and lose less LP), while worse players lose more LP (and gain less LP).
The problem is that there are many avenues to winning the game, and it's hard to figure out who contributed positively, who contributed negatively and by how much. An approach is to train a model on a huge set of games and try to more accurately judge how well players performed, and change their ratings based on that. Obviously, disclosing the factors and weights that play into this would be abused by players trying to game the system, so you wouldn't disclose that information.
Regardless, ANY metric other than the outcome of the game (win or defeat) is just that: a metric. Let's use KDA as an example. While a high KDA may pose a positive impact in many games, it is undeniable that dying may sometimes be the optimal play. Here's some questions I have:

Questions

• Would Thebausffs reach the same rank while playing the same way he did when he reached challenger with his horrible KDA?
• If the answer is "his bad KDA is compensated by high CS and turret damage", what about more nuanced situations: Instead of farming a minion wave, I may have decided to stay close to a team mate and saved them from a gank. I lost out on 105 gold, but my team mate survived. Am I not punished with lower LP gains for making the correct decision?
• Someone mentioned a metric like "skillshot hit rate". What if I use a skillshot to zone the enemy away from a cannon minion? My hit rate would decrease, but it would also deny 90 gold from the enemy. Do I lose out on 0,X LP for that?
• Is the argument that such metrics would only influence a tiny amount of the LP gain (e.g., going from +25 to +24)? In that case, would it even matter if the difference is barely even noticeable for players?
• Are you guys not worried about players attempting to game the system, even without factors and weights being disclosed? Low elo players already play for KDA or vision score instead of winning the game. Players would feel incentivized to play for these metrics rather than to win the game.
• Are you not worried about toxicity? Kill stealing would be equal to "LP stealing", junglers would get flamed more for not ganking a lane (because help from the jungler equals bonus LP).

Originally posted by Huzzl3

Thanks for the reply. In another comment I stated that I can see this making sense for seeding players, but if it's always active, then I don't think it matters whether my LP or MMR is affected, MMR will indirectly affect my LP gains anyway.

If a significant portion of the server started playing more towards KDA and won more but the game became more boring, would that be acceptable? (Assume playing towards KDA means less bloodthirsty, generally)

Very interesting question, seeing it as a way to nudge people towards playing better LoL. Definitely have to think more about it, but my initial thoughts are:
If those less bloodthirsty players won more games on average than they did before, I guess that means that the average game quality is better (as in, they play closer to optimal League of Legends). If that leads to the game being more boring, the balance & design teams could incentivize more bloodthirsty games to make it more exciting again. Though I now wonder, would the function to evaluate gameplay be updated every patch? How long would it take for it to reflect balance changes that make the game more bloodthirsty / exciting?

I think my main issue is just that the correct play might cause small penalties due to the model not learning every circumstance, so even if it's good for the majority, it would also hurt some players. I guess that raises another question: What accuracy would be acceptable in a system like this?

I don't have a real answer, definitely a tough problem to solve.