Corpus scope
The corpus contains ranked Solo/Duo games discovered from players on the supported Riot platforms. Current lane statistics cover Top and Middle. A match is assigned to one lane from Riot's recorded team position, and viewer lookups are kept separate from the baseline corpus.
Skill bands
Low is Gold through Platinum, Mid is Emerald through Diamond, and High is Master and above. “All ranks” combines the underlying wins and games from all three bands, then recomputes the rate and confidence interval; it never averages three rounded percentages.
Regions
Named-server tier lists use only that platform's games. “All servers” uses EUW and Korea together when their champion results agree closely enough under the project's equivalence test. When they do not, the interface labels the regional sensitivity rather than hiding it.
Patch rollover
New-patch games begin collecting immediately, but the previous mature patch remains live until the new patch has at least 25,000 EUW-and-KR corpus games in each skill band. Promotion is atomic, so one page never mixes a mature champion from one patch with a thin champion from another. The previous patch remains available for the change column.
Uncertainty
Win rates are accompanied by a 95% confidence interval and the number of games behind the estimate. Patch movement is marked as a real increase or decrease only when the interval on the difference excludes zero. A large-looking move from a small sample therefore remains explicitly uncertain.
Builds and runes
Builds and runes come from measured High-band games for the chosen champion. Purchase events are grouped into observed cores and timelines. The site reports the sample and does not claim one build is better when the observed outcomes do not separate at the available sample size.