Global Power Rankings in Esports: The Rating System Explained
In the competitive world of esports, fans and analysts seek a reliable way to measure and compare the strength of teams. Riot Games, the developer behind League of Legends, introduced a global power rankings system to provide objective, data-driven insights into team performance. By using an algorithm based on the Elo rating system, similar to those used in chess and football rankings, this system eliminates subjective biases. It provides a clear snapshot of the current power dynamics across regional and international teams. This article will explain how the Elo system works in esports, its benefits, and the intricacies of the formulas behind it.
The History of Elo Rating Systems
The Elo rating system was originally developed by Arpad Elo for chess, where it sought to quantify players' strengths based on their performance against opponents of varying skill levels. The system was later adopted by various sports, including football (for international rankings) and esports, as it offered a mathematically sound way to track team and player performance. Its adaptability made it particularly well-suited for games like League of Legends, where teams frequently compete within their regions but also face international opponents.
What is a Power Score?
The Power Score is the cornerstone of Riot’s Global Power Rankings for League of Legends. This score combines two key components: team Elo and league Elo. The aim is to give each team a score that reflects not just their individual skill but also the overall strength of the region they represent. This blended Elo system helps address the imbalance in the number of international games played, where certain regions historically dominate.
The formula for the Power Score is:
Power Score=(x×ELOTeam)+(y×ELOLeague)\text{Power Score} = (x \times ELO_{Team}) + (y \times ELO_{League})Power Score=(x×ELOTeam)+(y×ELOLeague)
In this formula:
- x and y represent the weights given to team Elo and league Elo, respectively.
- After extensive testing, Riot Games found that an 80/20 split (80% for team Elo and 20% for league Elo) gave the most accurate results, with a 65% match prediction accuracy.
The Role of Elo in Global Power Rankings
Elo for Individual Teams
Each team’s Elo score is calculated using an adapted version of the classic Elo formula. This system rewards teams for winning against stronger opponents and penalizes them for losing to weaker ones.
Elo for Regional Leagues
League Elo, on the other hand, reflects the overall strength of a region, taking into account international performances at events such as MSI and Worlds. A win by a team from a historically weaker region against a top-tier opponent significantly boosts the region’s Elo, which in turn benefits all teams from that region in the power rankings.
Formula Breakdown: Understanding the Math
Breaking down the formula for the Power Score:
Pafter=Pbefore+I(W−We)P_{after} = P_{before} + I (W - W_e)Pafter=Pbefore+I(W−We)
Here’s what each component means:
- P_before: The team’s Elo rating before the match.
- I: Importance factor, also known as the K-factor, which scales based on the stakes of the match.
- W: The result of the match (1 for a win, 0 for a loss).
- We: Expected result, calculated using the formula:
We=1÷(10−dr/600+1)W_e = 1 \div (10^{-dr/600} + 1)We=1÷(10−dr/600+1)
The dr represents the difference in ratings between the two teams. The larger the rating difference, the more expected it is that the stronger team wins.
Elo Adjustments Based on Match Outcomes
Elo changes are driven by the difference between W (the actual result) and We (the expected result). If a team performs better than expected (i.e., they beat a higher-ranked team), they gain more Elo points. Conversely, if they lose to a weaker team, their Elo drops more significantly.
The Impact of Match Importance (K-Factors)
Not all matches are equal in importance. Riot Games assigns different K-factors to matches based on their stakes. For example, matches in the playoffs or international events like Worlds have higher K-factors than regular season games. These K-factors ensure that critical matches have a greater impact on the team’s overall Elo score. The standardized K-factor values are:
- Regional Play:
- Play-Ins: 8
- Main Stage: 16
- Playoffs: 20
- International Play:
- Play-Ins: 12
- Main Stage: 20
- Playoffs: 36
League Elo: Strength Between Regions
League Elo is crucial for capturing the strength of different regions, such as North America (NA), Europe (EU), Korea (KR), and China (LPL). International results, particularly at events like the League of Legends World Championship, greatly influence a league’s overall rating.
When a team from a less dominant region defeats a top team from a stronger region, the Elo for the entire league gets a boost. This method ensures that regional strength is factored into the rankings, adding another layer of nuance to the global power rankings.
Evaluation Windows for Elo Updates
To strike a balance between current form and historical success, Elo ratings are evaluated over a 2-year window. This helps account for roster changes, regional shifts, and new strategies, while still rewarding consistency over time.
FAQs
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What is the Elo system in esports?
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The Elo system is a rating method used to calculate the relative skill levels of teams based on match outcomes.
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How does Riot's Elo system differ from traditional Elo?
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Riot’s system includes both team and league Elo to capture regional strength and adapt to the unique structure of League of Legends esports.
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What are K-factors in Elo ratings?
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K-factors scale the importance of matches, ensuring that high-stakes games affect rankings more significantly.
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How does the Power Score formula work?
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The Power Score formula blends a team’s Elo with their league’s Elo, assigning a final score that ranks LoL teams globally.
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Why does Riot use a two-year evaluation window?
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A two-year window balances recent performance with historical data, allowing for more accurate rankings despite roster changes.
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How accurate is the Elo-based power ranking system?
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Riot’s system achieves a 65
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The BoostRoyal Power Rankings
In BoostRoyal's power ranking system for boosters, we calculate a performance score based on the expected winrate for a booster at any given Elo. Achieving a score of 50 reflects meeting this expected winrate, while 100 was originally set as the believed maximum score that any human could achieve while boosting in League of Legends.
However, our top boosters have by this time managed to exceed this limit, with some surpassing scores of 100 over shorter timeframes. Scores of 90 are now common even throughout an entire season, showcasing extraordinary consistency and skill. It's important to note that even a score of 40 indicates an exceptionally fast climb, far beyond what an average player could achieve. Most average players, when playing in their own Elo, typically score between 0 and 20, as expected winrates adjust across different ranks. While an average player's winrate hovers around 50%, BoostRoyal's boosters operate at a much higher efficiency, demonstrating their unmatched ability to dominate the ranked ladder.
