Weighted Average Party Skill
Party Skill uses a Weighted Average instead of only using the highest-ranked player in the party. Weighted Average is a blend of the average of all players, then skews that average to the highest-ranked player in the party. A party of similarly ranked players will have a Party Skill close to their average rating. A party that’s farther apart in rank will match against players closer to their highest-ranked player.
Why is this necessary?
Our data shows that teams where all the players have similar skill ranks (all Silvers), tend to lose more often to a team where one player is ranked higher than the average (team with a Gold player). Teams with a much wider spread between higher and lower-ranked players tended to win even more often (the higher-ranked players carried the team).
Teams made of players close in skill (Silver 1 and Silver 3) have average win rates. Teams with a greater spread (Gold 1 and Bronze 1) tend to win more often against the Silver teams. This is because the Gold 1 player can carry the Bronze 1 player. Weighting the party’s average (skewing the average more to the higher-ranked player) lets us account for this advantage when matchmaking.
We think this is a good compromise. The original system used a simple average for all parties. Changes to that used the highest ranked player as a baseline. This new system uses a combination of the two. We will continue to monitor party win rates and will adjust how the weighted average is calculated if necessary.
For the math-inclined among you, we are taking the Root Mean Square of the party’s skills with a tuned exponent that is based on our data. Different exponents are used for Casual and Competitive.
Catching Up Lower-Skilled Party Members
We have adjusted how lower-skilled players in parties receive skill updates. This change fixes some exploits in the party system. The old method encouraged boosting lower ranked players and hurt the integrity of Competitive play. It also made it tougher for lower-rank friends to catch up in Competitive because it considered everyone equal. The new system rewards lower-ranked players more for beating a higher-ranked player. It penalizes losses less when playing against higher ranked players.
If a party member is at least one skill rank below the highest ranked player in the party the following will happen:
- The lower ranked player will receive more skill points for beating opponents who are ranked higher
- The lower ranked player will lose fewer skill points for losing to opponents who are ranked higher
A Few Important Notes
- Players ranked Champion and higher still use the weighted average above. However, the average for players in Champion Rank is weighted more towards the highest ranked player.
- Casual Playlists will also use weighted average Party Skill. But it is a “lighter” version. Casual parties will match slightly closer to their average than they would in Competitive Matches.
- This issue is important, and we are aware of all the feedback. We will continue watching how this affects casual and competitive matches.