Badge-weighted seeding (BWS) is a tournament seeding and restriction system that factors in each player's profile badge count as well as their global rank. Originally designed by DigitalHypno, the goal of the system was to "more accurately seed players and enforce rank restrictions based on [a] player's tournament badges",1 compared to the more standard seeding method of using players' global ranks directly.
The principle of BWS is that players are assigned a better seed if they have earned badges for playing tournaments in the past. This way, players cannot indefinitely stay at the same seed relative to other similarly ranked players if they perform well.23 In a set of tournaments that all use BWS, players that start at similar ranks are expected to tend toward BWS seeds that better reflect their likelihood to win matches against similarly seeded players.45
BWS was first used at the end of 2018 for Hippo Cup 2. Since then, it has been used in many community tournaments, and stands as one of the main seeding methods currently in use, alongside global ranks and qualifier rounds.
The original and most common method used to compute players' seeds in BWS is the following bounded decay function:
seed = global_rank ^ (0.9937 ^ (badge_count ^ 2))
badge_count
(≥ 0): Amount of badges on the player's profile that were earned as prizes for previous tournaments of the same game mode
global_rank
(≥ 1): Player's performance points rank on the global leaderboard corresponding to the tournament's game mode
This function satisfies properties that are important to the purpose of BWS:
global_rank
), at which there is an inflection point, and then the effect becomes the opposite.global_rank
. They are equal if the player has no badges.global_rank
.Some tournaments vary their implementation of BWS by using a different seed function,6 but all share the same properties described above.
DigitalHypno has stated that BWS is "ideally not a permanent solution to the problem", and advocates instead for a matchmaking ladder (or similar) to be supported by the game client.9
"What is BWS" section of Hippo Cup 2 forum post by this1neguy ↑ ↑
Discord message (1) from DigitalHypno in the osu! University server ↑
Discord message (2) from DigitalHypno in the osu! University server ↑
Discord message (3) from DigitalHypno in the osu! University server ↑
Discord message (4) from DigitalHypno in the osu! University server ↑
"BWS" section of Baku's Random Team Tournament #3 forum post by Bakugo- ↑
Discord message (5) from DigitalHypno in the osu! University server ↑