Blizzard Explains How Overwatch's Skill Rating Works

By Kotaku on at

By Justin Mahboubian-Jones

In spite of valiant attempts to avoid a fixation with my Overwatch Skill Rating, I have failed. My enjoyment of the game is now fixed to that fickle figure.

As I’ve become hooked on Competitive Mode, I’ve also become curious about its inner workings. How exactly does the algorithm/digitised brain of Jeff Kaplan running things behind the scenes of each Overwatch match decide how far to move me up or down the ranks? There are so many factors to consider when giving me a skill rating between 0 and 5,000 – what character I was playing, how my team was performing, how the opposing team was performing.

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According to Blizzard, the Skill Rating calculator takes all these factors into account, as well as information it has garnered about you. Many of those details are kept secret – after all, Overwatch players are a savvy bunch who could game the system – but Overwatch's principle designer, Scott Mercer, did clear up a few things about how Overwatch turns us all into numbers.

Surprisingly, your time spent 'On Fire' doesn't affect your skill rating at the end of a game. The 'On fire' system is a meter below your health that fills up as you play particularly well for your character. It doesn't give you anything to be 'On Fire', though it does let the other team know that you are a threat. A lot of players assumed that your time spent 'on fire' was directly tied to your Skill Rating. Players regularly fighting as Ana, Lucio, and Mercy recently claimed that, as a result of changes to the 'on fire' system, they were receiving smaller skill rating gains.

In fact, according to Blizzard, there is no direct link between the two. “While both the “On Fire” system and the matchmaking system attempt to track your underlying performance, the amount of time you spend “on fire” does not directly affect your SR adjustment after a match," said Scott Mercer, principle designer of Overwatch. "There is some amount of correlation between the two systems, but no direct link. We can make changes to one without affecting the other.”

The correlation here is pretty obvious: if you were 'on fire' for a long time during a match, you were probably kicking arse, and therefore your Skill Rating bump should be high. But 'on fire' time isn’t required to experience a large post-match gain as the systems are looking for different markers.

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To have a marked increase in your Skill Rating, you can't just have one amazing match. According to Blizzard, sharp shifts are caused by a discrepancy between where the matchmaker thinks you should be, and where you are. “If a player has multiple wins or losses in a row where they demonstrate this gap in perceived vs. actual skill, we further accelerate the adjustment as appropriate," said Mercer. "We want to minimise the number of matches that are created with players whose skill rating does not match their actual level of play. This results in improved fairness and quality of matches for everyone.”

Thankfully, the effect of streaks only applies to gains: If you’re headed skyward because you’re a cut above the rest, then Overwatch gives gives you a leg-up. The same isn’t true on the way down. “Repeated losses used to mean your SR would drop even more, but we recently reduced the effects of streaks so they don’t accelerate your SR adjustment,” said Mercer. “Sometimes a player does have a bad streak of losses, and that’s actually pretty natural. You might be temporarily distracted by something outside the game, you’re learning a new hero, or you are just simply unlucky for a time.“ Blizzard doesn't want to punish that because it will discourage players from experimenting.

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For that same reason, Blizzard measures your play by individual hero, not across the whole roster. “Your performance is compared to an internal historical report of what is a good or bad performance for that particular hero," said Mercer. "We don’t compare your performance on Mercy to how well you play on Reaper. This does encourage players to never give up on a match and try to win until the end.”

Overwatch players need to learn to love their skill rating: while it can cause joy and melancholy, it's with you for life. Blizzard has no plans of resetting ratings between seasons. "Doing that would result in a great deal of chaos as the matchmaking system’s perception of everyone’s skill would be really poor until everyone has played a lot of matches,” explained Mercer.

There are still elements of the skill rating calculator hidden away in a black box, but it's heartening to know Blizzard designed the system to account for and encourage experimentation, to reward our best days and not hammer us on our worst. It imbues that seemingly arcane number with a little more of us.