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RNG 101: How Random Chance Defines Pro Play
Random elements in competitive games are hotly debated, but there are some unexpected positives.
Random number generation, also known as RNG, has been a critical part of gaming since we moved past the Pong era. Random chance is accepted as welcome and even fun when it comes to loot tables or rpg crit chance, but when it is introduced into eSports, things quickly get messy. Competitive gaming is meant to be a pure expression of skill, and the more random elements a developer throws into a game, the less purely competitive it becomes. (There’s a reason why League of Legends is the biggest pro game instead of the latest Mario Party.) Some fans would love it every pro game had RNG stripped away entirely, but the result would likely be a flatter, less rich eSports ecosystem. It’s time to pay tribute to RNGesus and dive into how, exactly, random chance can enhance a competitive game.
The Elder Dragon shows up after some random pals
© Riot Games
What counts as RNG?
To understand RNG in competitive play, we talked to Greg “Ghostcrawler” Street, Lead Game Designer on League of Legends and former Lead Systems Designer for World of Warcraft. Ghostcrawler defines RNG as a binary: input variation, and output variation.
“Input variation is that the game board isn’t the same,” he explains. “As a player, you need to make decisions and evaluate based on that.” When it comes to input variation, League of Legends has the plants system, and the random dragon spawns. Heroes of the Storm offers a smorgasbord of maps with objectives that spawn in different locations, such as Tributes that show up randomly on the map at a set location, or a random Shrine igniting and forcing the players to contest that objective.
Dragons are, in Ghostcrawler’s opinion, a great example of input variation. “What dragon spawns next is random (with some bad luck protection), but it’s not a surprise. Players can react to that and it won’t determine the outcome of the game.”
The more dangerous form of RNG is output variation. “Output variation is when I decide to attack the champion, the computer makes a dice roll, and decides. That can feel like bullshit," says Ghostcrawler. This would include critical chance in League, which Ghostcrawler refers to as an “unsolved problem,” as well as Twisted Fate’s gold generation passive. One game that does have output variation on a character’s kit is Dota 2, where Ogre Magi is based and balanced around RNG on his Multicast ability.
Ogre Magi breaks the mold when it comes to RNG
© Valve Software
Finally, there’s a game like Hearthstone, which is engineered around random cards like Barnes or Yogg-Saron being dropped. Navigating random chance in Hearthstone is the name of the game, and players have to keep their heads above water and roll with the punches.
It’s possible for games to harness RNG and restrict it by setting up barriers, of course. Twisted Fate’s passive can net him six extra gold per minion (and the formula is weighted for him to get payouts on the higher side, since he’s a gambler), but he can’t get 600 gold. Heroes of the Storm maps with randomized objectives offer a limited amount of spawn points. Just because we’re getting a little random doesn’t mean all of the rules get thrown out the window!
A roll of the dice adds complexity to a game
© skitterphoto.com
How I learned to stop worrying and love RNG
In order to understand why RNG is so useful, we first have to understand the concept of perfect play. Perfect play is the concept that a game can be "solved." If two people sit down to play tic-tac-toe, every game will end in a tie once they understand it. There are more complicated competitive games that have been "solved" in a similar way; League of Legends's 3v3 mode is often criticized for the fact that there’s only one viable "team comp" and a very small pool of champions that are successful. Even chess has been called "partially solved," in that many tactics have been removed from play and there are a mandatory set of moves a player must make to succeed against a skilled player.
“We think of RNG as a tool to be deployed in cases where the game becomes too predictable,” says Ghostcrawler. “If a competitive game plays out the same way every time, it’s boring. Randomness mixes things enough so that it doesn’t play out the same way. Games need unpredictability. Even in a 10-player game like League of Legends, you run into situations where things play out the same way every time. If you have two champions auto-attacking each other, and champion A hits champion B, and you can see the damage being done and calculate it, anyone will be able to quickly say, “Oh, I do more damage than I’m taking ...” and figure out how the fight is going to go.
Even with this in mind, RNG must be deployed very carefully. Characters like Ogre Magi, which rely heavily on output variation, are an exception. League and Heroes of the Storm both use input variation on the board, instead. Map objectives will spawn, but give the players warning. The players, instead of capitalizing on a huge random burst of damage they couldn’t predict, are forced to respond to random elements and come up with strategies to deal with a shifting landscape. “When three Infernals spawn, it’s exciting [as a viewer], but the players know what to do. It creates situations where if you have two stacks, and a third infernal dragon spawns, you really need to contest that dragon. If a water dragon spawns, you can decide differently. The way that this information is presented to players is really important.”
Heroes of the Storm relies on input variation.
© Blizzard Entertainment
“Players tend to overemphasize mechanical execution as the definition of skill in League of Legends,” Ghostcrawler continues. “There are a lot of other skills that we try to test: teamwork and communication with four other players, and good decision making. The reason we go for variants with things like dragons is we want people to respond to what's happening in the moment, rather than knowing how things are going to play out based in champion select from picks and bans.
Heroes of the Storm chooses to have a wider expression of hero potential and then give those unique heroes chances to show their teamwork on a unique set of battlegrounds that focus heavily on input variation. Even the inclusion of multiple battlegrounds sets it apart from other games, forcing players to pick and plan around the unique objectives on each map. Infernal Shrines, Towers of Doom, Cursed Hollow and Warhead Junction all offer randomized spawns, creating games that will never play out the same way, but reward players who can think quickly and respond to this new information.
See this point? Contest it!
© Blizzard Entertainment
Heroes has some really out there character concepts, like the two-player piloted champion Cho’Gall, or the hat distributing Abathur who sits in base and buffs his allies. Champions are offered a constant stream of choices through talent trees, which allows them to further adapt. Does Morales want to be able to boost up their Valla, or would she rather give the team a lift to a Shrine with a Medivac? Does Jaina want to dish out extra damage and eliminate priority targets, or does she want to be a crowd control bot who locks down the enemy team? The map, and the battleground, forces the players to make smart choices and adapt their heroes to face the challenges ahead.
Players like FlyQuest’s Hai tend to bloom in games that allow for teamwork focused squads to excel over a group of purely mechanically gifted players. By opening avenues for smart players to shotcall through complex systems, you create a game where the right call at the right time under complex systems can pull ahead, even against a more mechanically skilled team.
In short, RNG ensures that players are always challenged and viewers are always entertained. Ghostcrawler explains, “From the standpoint of a competitive sport, you don’t want the best team to win every single time. That’s boring. We had a very exciting Super Bowl this year because it was hard to tell what was going to happen. If it was just a shutout, viewers would have been much less engaged. You don’t want it to be completely up in the air, you want a suspicion that when SKT goes against ROX, it’s not a foregone conclusion; ROX could pull a big play and fix it.” RNG isn't an all-controlling force, so ideally the best team always wins ... but there’s always that chance.
Reining in RNG
Gnar was a challenge in accessibility.
© Riot Games
While RNG can keep a competitive game going, it’s important to distribute it in small doses. A 10-player game already has a boatload of variables; throw in systematic randomness to the game, and things can get unreadable and out of control real fast.
Adding RNG to a champion’s kit is also risky. When League came up with Gnar, a champion built around a slowly building rage bar, they knew that his kit being unreliable and partially inaccessible would feel random and unsatisfying. “We talked a lot about the randomness of Gnar’s transforming," says Ghostcrawler. “We knew if it was too extreme, he would be out of professional play.”
Another champion who uses RNG is Bard, who has helpful chimes that spawn randomly all over the map. “That system is really complicated behind the scenes; we wanted to make sure it wasn’t completely random. There’s a lot of protection going on in the code that decides where and when those things spawn, and how far away they are. In a bell curve, we compress the extremes.”
Bard's chimes are very complex behind the scenes.
© Riot Games
Some games have completely embraced RNG. Hearthstone has leaned into random chance — it is a card game, after all. Other games, like Overwatch, have completely eliminated RNG. Overwatch’s hero switching means that the battlefield is always shifting as players switch as needed; throwing random crits or randomized abilities into the mix is more chaos than a skill-based competitive game likely needs.
To make things even more complicated, players can sometimes react negatively to RNG, fearing that a new system will remove the competitive aspects of their favourite game. Riot learned this lesson with the plants system. The team released an update showing off randomized plants that let players propel themselves through the air, gobble up extra health, or get vision. It captured a little bit of the Heroes randomness that gave players opportunities to make choices and translate them into big plays.
The response was a massive outcry from the community. Players critiqued the system as removing skill, cluttering the map and adding an unnecessary minigame element. While the plants system did make it into League of Legends, many of their random elements had to be uprooted. “The system we conceived was really variable,” says Ghostcrawler. “It was different to the one we shipped with, and we had to back off on that due to player concerns.”
Riot revealed plants with a post that was, according to Ghostcrawler, “high on flash and low on detail” - and players panicked. “We shipped messaging that had people using the movement plant to get a dragon steal and win the game, because that makes an exciting video, but the message we sent to players was that plants would have a huge effect on whether you guys win the game. It wasn’t the intention — a plant should never allow a weaker team to win — but we had to retreat a bit, and because of it, it’ll be hard to go back to a new system with more variable spawning.”
Where are your friends? Mine were all around :(
© Riot Games
While the League developers were disappointed to change the plants system, it was a valuable lesson. Players largely associate RNG with cheese or unfairness and see it as absolutely antithetical to a competitive situation. And while RNG is meant to enhance a competitive game by providing variables for players to work around, it has picked up an unfortunate reputation as something that allows inferior teams to win thanks to pure luck.
RNG may be an essential element to competitive games, but it's like a strong spice that can quickly overwhelm a dish. Developers must be careful to slowly add RNG in small amounts, and to ensure that when it's added, it enhances the competitive aspects of a game instead of removing them. While there are still imperfect RNG elements in a game like League, such as the critical system, overall it can be a boon.
The biggest hurdle that RNG faces is player perception. When developers add a new RNG element, it’s likely tempting to show the system off and envision the madcap hijinks that can come from its inclusion. The truth is, players already love RNG and have been dealing with it for years in their favorite games — they just need to understand the tactical and strategic elements it offers. If developers can master their messaging, we’ll likely see competitive games embrace and roll out those (controlled) random elements for years to come.
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