Badge-weighted seeding

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.

Technical

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:

• A player's seed decreases in larger increments as they attain more badges, or in other words, each badge is worth more than the last.¹ Note that in the formula above, this is only true until around 2 to 6 badges (depending on global_rank), at which there is an inflection point, and then the effect becomes the opposite.
• BWS seeds are always less than or equal to global_rank. They are equal if the player has no badges.
• BWS seeds have the same range as global_rank.

Some tournaments vary their implementation of BWS by using a different seed function,⁶ but all share the same properties described above.

Potential drawbacks

• BWS can only be updated when players receive badges, and badges are typically only given as first-place awards at the end of tournaments, so the process of settling players into accurate seeds can be very slow.
• Badges awarded for rank-restricted tournaments continue to affect players' BWS seeds even after their ranks are outside of those rank ranges.⁷ In general, it can be viewed as a drawback that all badges are treated equal, despite the many differing factors between tournaments that cause badge prizes to be more or less difficult to win.

  • Some more experimental versions of BWS include mechanisms to address this.⁸
• Extra work is required from tournament staff to determine which badges are relevant to the tournament and compute BWS.

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

References