8Realms uses bespoke software and databases to generate ranking and ratings for the UK Age of Sigmar community, built around the Elo rating system. Our system provides an accurate, balanced, and community-focused framework for ranking AOS players. This article explains how 8Realms actually calculates these ratings, so that all players understand what affects their rating and how the 8Realms system works.
What Counts Towards the 8Realms Rating?
Every system is different, and the 8Realms system – like all ranking systems – must choose an approach and stick to it. 8Realms counts all competitive singles matches towards a player’s rating. This is any match at any event which is managed on a major tournament platform, currently defined as Best Coast Pairings and Stats & Ladders. To keep our use of this third-party data fair, we do not accept manually submitted tournament data, which ensures that these platforms do not lose out financially from 8Realms’ fair use of the data on their platforms.
We will manually exclude any event which specifically states that it is “Narrative” in nature in the title or description, as we understand that the focus of these events is different and engagement with the hobby trumps raw match performance. However, if an event is not explicitly states as narrative, it is likely to be included and may need to be manually removed from the ranking dataset.
Although it is technically possible to count doubles and teams matches, we have decided not to count these. Sometimes a player may face a series of practically unwinnable matches as part of an overall team strategy, and likewise a player with a specialised list may face a series of ideal matchups to build the team’s score. We recognise that this is part of the essence of a team or doubles event, and do not wish to disadvantage players who engage with this aspect of these events.
So, to see your 8Realms UK rating change, you need to attend a competitive singles event in the UK which uses a major tournament platform. This can be any length, even just 1 round, which means that ‘league’ events will also count as long as they are competitive and recorded on a major platform. The next step to understanding your 8Realms rating is to understand the Elo system which underpins it.
Understanding Elo Ratings
The Elo rating system, first used in chess and adapted for various competitive games including online gaming giants like League of Legends, is a method for calculating the relative skill levels of players. In the context of AOS, Elo ratings provide a dynamic measure of a player’s performance, updated continuously as matches are played.
At its core, the Elo system updates player ratings based on match outcomes. Each player’s rating adjusts based on their performance against other rated players, with unexpected outcomes (like a lower-rated player beating a higher-rated player) having a more significant impact on the rating adjustment. To decide what outcome is expected, the Elo system uses the following formula:
EA = 1/(1 + 10(RB – RA) / 400)
where EA is the expected score for Player A, and RA and RB are the Elo ratings of Player A and Player B, respectively.
Once a match has taken place, the Elo system then uses these to calculate new ratings, using the following formula:
R’A = RA + K(SA – EA)
where R’A is the new rating of Player A, SA is the actual score (1 for a win, 0.5 for a draw, 0 for a loss), and K is the development factor, which is explained further below.
8Realms Ratings in Practice
Consider two players, Alarielle and Belakor, with current 8Realms ratings of 1500 and 1600, respectively. If Alarielle plays against Belakor in a tournament, the first equation gives us Alarielle’s expected performance. Think of this as the probability of winning between 0 and 1:
EA = 1/(1 + 10(1600 – 1500) / 400) ≈ 0.36
In effect, the system predicts that Alarielle has around a 36% chance of beating a player with Belakor’s skill level. This means that if she does win she has performed better than expected, which means her 8Realms rating should be revised upwards to more accurately reflect her skill level. As it happens, Alarielle does win! The second equation is now used to update her rating:
R’A = 1500 + 20(1 – 0.36) ≈ 1512.8
Alarielle’s new rating is 1512.8, which means that her 8Realms rating is one step closer to reflecting her true skill level relative to the community as a whole.
You can see how this ‘expected performance’ system is crucial to keeping the scores fair. A higher skilled player might have a 95% or higher likelihood of beating a much lower skilled player, and will receive very few additional points from consistently beating lower skilled players. The development factor, or K-factor, enhances this further to create a better experience for all players.
Understanding K-Factors
The K-factor effectively determines the sensitivity of a player’s rating to match outcomes. The K-factor affects the maximum amount of points a player’s rating can change from a single game. This is important for a variety of reasons, each of which warrants a different K-factor:
- New Players (fewer than 25 games): A K-factor of 40 allows for rapid adjustments as players begin to establish their initial ratings.
- Experienced Players: Once players have completed more than 25 games, the K-factor reduces to 20, providing a balance between rating stability and sensitivity to recent performances.
- Elite Players (ratings reach 2400 and above): A K-factor of 10 is used to prevent dramatic shifts at the top of the rankings, ensuring that high-level players don’t gain excessively from victories over average players. The threshold for this is likely to decrease as the 8Realms system develops, to target the highest skilled players and prevent excessive gains or predatory event behaviour.
These differing K-factors ensure that the 8Realms system accurately reflects a player’s current form and experience level, adapting as they progress through different stages of competitive play.
How 8Realms Updates Ratings
8Realms automates the process of updating Elo ratings through a bespoke data integration system that interacts with major tournament platforms such as Best Coast Pairings and Stats & Ladders.
- Data Collection: After each tournament, data regarding match outcomes and player interactions is automatically imported from the platforms.
- Data Parsing: This raw data is then parsed into a structured format suitable for analysis, populating a master database that holds all relevant information for AOS player rankings.
- Rating Algorithm: Using this database, an algorithm iteratively processes each match’s result, adjusting player ratings according to the Elo formula and considering the appropriate K-factor for each player.
This approach ensures that the 8Realms rankings are always up-to-date and reflective of the latest competitive results, providing a dynamic and accurate leaderboard that is invaluable for players and tournament organisers alike. Most importantly, it does not rely on tournament organisers manually sending in data in a specific format, and the highly automated process makes it easy for the volunteers running the tool to maintain 8Realms into the future.
Benefits of the 8Realms Elo System
8Realms offers a number of key benefits to the UK AOS community:
- Skill-Based: Unlike traditional systems that may prioritize event attendance or placement, the 8Realms rating is purely performance-based, ensuring that only your gameplay affects your rating.
- Balanced Across Events: All events, regardless of size, contribute equally to your Elo rating. Your performance is what counts, making every game and every round critical.
- Fair and Competitive Matchmaking: With accurate ratings, players can find opponents at similar skill levels, leading to more engaging and challenging matches. This not only enhances the competitive experience but also aids tournament organisers in setting up well-balanced Round 1 matchups.
Limitations of the 8Realms System
It is important to be upfront about the limitations of any system. There are aspects of the 8Realms system, such as only counting singles events, that some players may see as limitations, however these rely on value judgements rather than mathemtical limitations. There are two mathematical limitations of the 8Realms system:
- Quantity of Matches: The main limitation of the 8Realms system is that it requires quite a lot of matches before a player’s rating can be considered ‘truly’ accurate. Typically an Elo system requires a player to complete around 25 matches before their score is considered truly accurate, which is why some 8Realms ratings are italicised and marked as provisional when the player has not yet completed enough games to have a ‘true’ rating. This doesn’t mean that an italicised rating is inaccurate, as this does reflect a player’s performance, it just means that the underlying maths has not yet provided a high enough confidence level to be sure. This is the case with any ranking system, especially in the early stages of something like a new edition or league, as players effectively ‘sort’ themselves into a ranking based on performance over time. This is why large sporting events often have a ‘group’ stage to determine average performance before a ‘knockout’ stage. Once many players start achieving ‘true’ ratings, an option will be added to 8Realms to exclude provisional ratings from the ranking, which is particularly important for players with ratings below 1000. A typical chess tournament consists of 3-5 rounds, so Age of Sigmar aligns with how the Elo system was originally designed. However, many players will take several months to achieve a ‘true’ rating.
- Relative Performance: The 8Realms system, like all Elo systems, technically only measures relative performance. This means that if a population (ie all UK AOS players) are significantly better than average players, then your rating will be lower than for an average player. This doesn’t really matter for something like a UK ranking system, as long as all players in the population are included – which for 8Realms, they are. However, this means that an 8Realms UK rating cannot be directly copmared with an Elo rating for another population, such as US players.
Despite these limitations, the 8Realms system is still a valuable means of ranking and rating competitive players across the UK community. This community focus is an important part of what 8Realms does.
Our Community Focus
Our system supports the AOS community by encouraging participation across all levels of play, from local tournaments to major championships. It shifts the focus at tournaments from reaching the highest numbered table to performing well against challenging opponents, making the game more enjoyable for everyone, particularly players who compete regularly and want to stay engaged and track their performance as a player.
Summary
By leveraging the Elo system’s tried and tested framework, 8Realms delivers an accurate and balanced ranking solution that enhances the competitive experience for AOS players. As we continue to refine our processes based on the experience of AOS 4, 8Realms remains committed to serving the AOS community with the most accurate and responsive competitive ranking tool available.