I collected arenas stats over 186 games with my duo (Feb 15 to May 28th)
Most charts exclude my duo and I as our presence in every match makes us an outlier and would lead to skewed data (eg. increased Mage pick rate).
This project began during a series of ~40 abysmal games with a 30% WR. My duo and I began to get suspicious about matchmaking and I started collecting and aggregating data in hopes of finding proof (and cope). While we did find that the average rank spread for a match is INSANE and that MMR adjustment seem far too slow, our MMR did eventually adjust (see bottom-most graph, Feb 15 to 25th).
I ended up finding the process really satisfying, and we were still a bit suspicious, so my duo and I agreed to continue playing League exclusively with each other to keep our MMRs free from external variables. I continued to build more charts for fun and cope, and the result is what you see here!
What about Augment and Pristmatic Item Stats?
League's API ToS specifically disallows presenting winrates for Augments and Items. Super sus, but I'm not trying to get banned over this.
Can I customize it?
Webapp with knobs and stuff: https://damrnelson.github.io/arena-stats/ (No ads/monetization, this is just for-fun)
Source code: https://github.com/DaMrNelson/arena-stats