MATCHMAKING

In the past, we have released a post touching on how the MMR system works. We are updating it to properly reflect the current system in Rainbow Six Siege.

How does it work ?

Skill

Your skill represents your ability to win a game. Comparing two teams' skill gives you the probability that one team will win against the other. The higher the difference, the more likely a given team is going to win. When two teams with the same skill levels are matched up with each other, they both have an equal shot at winning. The algorithm used in Rainbow Six Siege assigns two values to each player: an estimation of their skill (μ) and the uncertainty of this estimation (σ). The players’ skills are distributed along a Bell curve, centered around 25 (High Silver – Low Gold).

Uncertainty

The estimation of your skill is probabilistic. In general, the more games you play, the more information we have about you, and the more confident we are about this estimation. This confidence is represented by the uncertainty value sigma (σ). The lower the uncertainty, the higher the confidence.

Link between skill and MMR

Early on in the game’s first year, your rank was partially also determined by your engagement with the game. This led to confusion as the play experiences of players of different ranks would vary greatly.This has not been the case since Year 1 Season 4 and presently, your MMR only takes into account your skill (MMR = 100*μ). This also means that your clearance level has no impact on your MMR.

MMR Update

The MMR is updated solely on the outcome of your match. If this outcome is unexpected (for example, you lost against players with a lower skill than your team), the skill updates will be more substantial, and vice-versa. In addition to that, the more confident we are about your skill (i.e., if your σ is low), the smaller the updates will be.

Let’s take a simple example with only two players: Hibana vs Pulse. The values in this example do not reflect the actual updates that would happen with our system but it should give you an understanding of the situation. Hibana is a Gold player (μ ≈ 29), and has been playing at that level for quite some time. Hibana’s rank has a low uncertainty value attached to it, so σ ≈ 3. Hibana faces Pulse (a Copper ranked player, but he has a lot of heart), and loses. Due to the low uncertainty value, it is likely that Hibana just had a bad game, so her skill level would decrease, resulting in μ ≈ 28. This is due to the system taking into account the rank of the enemy you have lost to. If Hibana lost to someone that was Gold, the adjustment would be closer to μ ≈ 28.5. Losing to a Diamond would have resulted in a change to μ ≈ 28.9.

That being said, Pulse is still relatively new to the game, and our system is attempting to determine where he should be placed (μ ≈ 17 and σ ≈ 6). By Tachanka’s grace, Pulse won the match, so we would increase his skill level to 20. His victory against Hibana has helped us to determine that he may be a better player, so his uncertainly has dropped a small amount (σ ≈ 5.5). The large increase in skill level rating for is a result of Pulse being a fairly unknown player, and our confidence in Hibana’s placement.

Unified MMR

In order to prevent matchmaking abuses while switching regions, we’ve changed our Matchmaking Rating system in Y5S2 to unified MMRs for each playlist. This means that you will not have different MMRs depending on the region you play in. However, your matchmaking ranking will remain separate in different playlists.

Quick Match Playlist

(formerly Casual)

This is the standard multiplayer playlist offering a fair environment for beginner and intermediate skill levels to play in.

Quick Matches are available for all players, do not affect the players’ ranking in Ranked and offer 3 game modes: Bomb, hostage and Secure Area.

Quick Matches and Unranked Matches use the same MMR.
Therefore, winning/losing in one will affect your MMR in the other playlist as well.

However, MMR used in Quick Match is not linked to the MMR used in Ranked. Therefore players that mainly play Ranked, and rarely enter Quick Match have an MMR in QM that does not reflect their real ability. We think that that may be one of the reasons why QM is considered unbalanced. Unless they enter from time to time to update their QM MMR they will currently have this issue.

In the past we’ve tested several methods with the goal to provide all Quick Match players with a best possible matchmaking experience. Since Y2S3 the Quick Match matchmaking pairs players based on an independent and hidden Quick Match / Unranked Matchmaking Rating (MMR). This Quick Match / Unranked MMR is based on the same system described above, taking into account your performance in both, Quick Matches and Unranked. It is not tied to your Ranked MMR at all, nor visible to you or other players.

New players are provided with a base line MMR, which is more on par with where a beginner should be. A lower starting point for beginners means that they will be able to increase their MMR in a pool of players with a comparable skill level. This lower MMR rating will be erased over time as they win more matches, eventually placing them where they truly belong based on their skill level.

Unranked Playlist

The leap from Quick Match to Ranked can be overwhelming due to the stark difference between competitive and casual players in terms of mentality, playstyle, and even personal comfort level. This gap was the driving motivation behind the creation of the Unranked playlist, which was implemented in Y4S3.

Unranked is a multiplayer playlist, available for all players with a Clearance Level above 10. It follows the Ranked ruleset, but has no Rank restrictions (which will be detailed further in this article) and doesn’t affect a player’s Rank or Ranked MMR. Unranked shares the same hidden MMR, which is used for Quick Match matchmaking as well and pairs players based on the same system. So whether you’re into competitive gameplay but would rather do without the pressure of a ranking system, or you want to get familiar with Pick & Ban and other associated features before heading into Ranked, this is the playlist for you.

Its advantage over Ranked is that you don’t need to meet the MMR Restriction as you do in Ranked. This, along with the lower CL compared to Ranked allows you to join a squad that do not meet the requirements for Ranked but still play with competitive rules.

Keep in mind, however, that Ranked policies also apply to this playlist, and any sanctions you incur in it will also apply to the Ranked playlist.

Ranked Playlist

*The distribution above may vary depending on the Season.

Ranked is the competitive multiplayer playlist, which becomes available to players upon reaching level 50. Next to a smaller map pool and bomb being the only game mode available, this playlist features a ban phase, allowing both teams to choose and ban an Attacker and Defender.

Ranked features 23 skill ranks. These ranks are based on a players Matchmaking Ranking (MMR) which is derived from numerical scores generated by the TrueSkill algorithm as described at the beginning of the article. A player's skill rank is first obtained after successfully completing 10 ranked placement matches.

Which elements can affect ranking?

MMR changes are based on:

• The relative skill levels of the players/teams in the game.
• Whether or not the player won the match.
• Large skill difference between teams has a dramatic outcome based on who won the match as per the previous Hibana/Pulse example.
• Prematurely exiting a ranked match always counts as a loss toward skill ranks, even if their team won
  • Abandoning a match or inactivity are all included.
  • Connection issues do count as a loss but not as a win if their team won.
  • When internet connection is lost then restored, the player is given an option to re-join the match instead of taking the penalty.

Personal performance

Your personal performance as your score or your kill/death ratio does not impact the number of points you get.

If you get 15 kills per game but lose all of them, then your ability to win a game is very low, hence you should be ranked very low too. Conversely, a player that does not land kills, but still wins often, should be ranked quite high (maybe they make excellent callouts, which is an important factor in a team’s ability to win). The idea is that if you play well, and are an asset to your team, you will naturally win more matches in the long run. This positive influence on winning matches is what we measure.

Gaining/losing different amount of points among a team

If you both have the same skill, the update will depend on how confident our system is regarding where you are placed. Let’s say that you are both Gold IV but your friend has played a lot more games than you (they have a low uncertainty), you will gain/lose more points than they will.

Squad MMR restriction

In Y4S3 we’ve implemented a limit to the MMR gap between party members. There cannot be a bigger gap than 1000 MMR between the players with highest and lowest MMR in the squad in order to play Ranked. Players can check their squad members' MMR in the Side Panel Profile. For players above 4400 MMR (Diamonds), you are able to group with any player above 3400 MMR (Platinum). Players below 1200 MMR can group with players below 2200 MMR.

This was partially done to reduce the impact of boosting, but, of course, to also encourage a more balanced matchmaking environment.

Champions Rank

Once a player reaches 5000 MMR, and has completed a minimum of 100 matches, they’ll enter the Champions rank. While it mostly functions like other ranks, it has something that ups the ante: individual rank numbers. The top 9999 players with the highest MMR within the Champions rank will have their standing displayed on their rank, which means that whichever players have the highest MMR in the game will be recognized as the #1 Champions.

This doesn’t mean, however, that Champions who aren’t currently in the top 9999 will be taken down to Diamond. As long as you remain above 5000 MMR and have more than 100 completed matches, you are a Champion.

Soft MMR Reset

At the beginning of every new Season we perform a so-called Soft MMR Reset. This means we are resetting the ranked MMR of all players between the “middle” (2500 MMR) and their rank from the previous Season, with extremes above 3500 and below 1500 clamped to those respective values. This also applies to placement matches.

Before Y4S2, we reset all players to a 2500 MMR at the beginning of the new Season. We changed this in order to improve the matchmaking experience at the beginning of a Season. This change leads to players reaching their “true skill” faster; players that should be Diamond will reach Diamond faster. We understand that some players, particularly those at the extreme high end of Diamond, would like more of a “grind” implemented for attaining the higher ranks. We have heard these concerns and are working on how to provide that type of experience for those who want it in the future.

SEASONAL CHARMS

At the end of every season, players receive a charm based on the highest rank they’ve managed to achieve during that season.

For example, if you reached the Diamond rank but finished the Season with a Gold rank, you will receive the Diamond charm.

Please note that if your MMR has been reset due to drastic MMR changes, you will not receive the seasonal ranked charm for your highest rank prior to the reset.

MMR Rollback

What is this feature?

This feature’s goal is to help reduce the long-term impact cheaters may have on other players’ seasonal rankings.

When a cheater is sanctioned, the feature will roll back any rating gains and losses for all players from matches that the banned player took part in for that season. This cancels all games that the Cheater played for all parties.
Please note that you cannot go beyond your maximum MMR for the current season as a result of a roll back.

More information on the MMR Rollback feature can be found in this article.

Impact on boosted players

Part of the reason we are doing this is also to push back against boosting services or players that use cheats to boost accounts or exploit the integrity of our ranked system in other ways. After those cheaters are banned the boosted accounts would receive drastic MMR changes through the MMR Rollback, which is a sign of massive irregularity and a red flag in our system. This is why we started resetting MMR for players with drastic MMR changes since Y4S3.3.

This means that instead of undergoing a significant change in MMR, players will have to redo their placement matches to get back appropriately on the ladder. Players who have their MMR reset will also not receive the seasonal ranked charm for their highest rank prior to the reset.

Rollback conditions

The current Roll Back feature will roll back all games (victories and defeats) the banned cheater participated in. We also explored a few other options, but based on the results of the data, rolling back all games will help to maintain a stable MMR environment, while still reducing the impact of cheaters on games.

Timing

Due to our process of detecting cheaters, and then the subsequent banning process, there is no way for us to identify which specific matches a person cheated in accurately (such as when players toggle their cheats on/off prior to being caught). With this in mind, we also explored the possibility for limited MMR resets based on recency, and tested MMR resets for the last 7 days vs the entire Season.

However, the results were too random, and there was no way to determine if we had actually reduced the entire footprint of their negative behavior. So in order to confidently ensure that we maximize our removal of the impact of a cheater, we are resetting the MMR from matches that player participated in from the entire Season.

MMR Rollback Adjustment

We have noticed that the system itself induced quite a lot of frustration for our most dedicated players.

Therefore, we have decided to tweak the system at some point during Y5S3 and to expand the highest seasonal MMR value up to a fixed number of points. This means that you should still receive meaningful adjustments even if you are at the highest MMR value of your Season. This should lead to a significant reduction of neutral MMR adjustments (receiving 0 points).

If we define the additional fixed number of points you can earn above your maximum MMR value to 10 (disclaimer: it’s not). And if 3000 is your current and highest MMR ranking this season, any positive adjustment will still increase your MMR value beyond 3000 and up to a maximum 3010 MMR points.

We will monitor closely the impact of this change on the MMR economy and adjust the fixed number of MMR points (10 in the example above) based on your feedback and on our data.

An update will be shared as soon as we have a more definitive date to announce.

Going Forward

We want to let you know that we have heard some frustrations around the current MMR Rollback feature. We understand that losing MMR due to winning against cheaters or not gaining more MMR than your seasonal peak can lead to some frustrations for players. We are currently planning to revisit the MMR Rollback feature to explore if we can reduce these frustrations for our players in the future while still effectively cancelling out any effect cheaters have on matches.

Furthermore, the Matchmaking Ranking system as a whole is quite a complex system. We know that it can cause frustration amongst our players, when they feel like the matches are unbalanced and not fair for them. It is difficult to find the sweet spot between short queue times and balanced matches on all playlists and we always work on improving our system and its functionalities to give you all the best possible matchmaking experience.

Your feedback is – and always has been very important to us. Therefore, we want to encourage you once more to share your feedback on the Matchmaking Rating system and the MMR Rollback feature, and what kind of improvements you’d like to see.

We are looking forward to reading your thoughts on Twitter, Reddit and on our official forums.