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Design 101: The Role of Randomness

It's the dynamite of game design. A powerful tool, but if you're not careful it can blow up in your face.

Dan Felder, Blogger

September 16, 2015

20 Min Read




Hey everyone, welcome back to Design 101. Today we’re going to talk about one of the most controversial aspects of game design, the role of Randomness (or RNG). Few topics inspire more passion in designers and player communities alike, especially in strategic titles. We've got a lot to get into, so let's get started.


RNG - The Hated One

RNG has a truly terrible reputation among many gamers, particularly competitive players. There are a huge number of reasons for this. Here are just a few.

  1. Your decisions can feel less important, because you know they might be trumped by randomness. This can make you feel less invested in your turns.

  2. Randomness leads to unfair results. The more skilled player doesn’t always win. This can create frustation at the injustice.

  3. Many RNG designs, like Hearthstone’s Mad Bomber, have a chance to backfire against their players. While some players find that exciting, most players hate it.

However, if randomness was universally bad then no one would be playing cardgames. Many competitive players decide to dedicate themselves to mastering a title in this genre. Just check out the MTG Pro Tour Circuit and the sheer amount of strategy content generated each and every week purely for that game's competitive play.

If games were just better without randomness, especially for competitive play, this wouldn’t be possible. What’s going on?


It's easy to see the issues with RNG. I've seen many new designers seek to improve their favorite genres by eliminating it entirely. Yet RNG is just like any other tool. Properly used, there are many different benefits it can provide your projects.


Let's dig in.

Randomness Adds Variety

Randomness ensures that games play out differently. Shuffling your deck ensures that your games will play out differently depending on which combination of cards you draw. These are major benefits for keeping a game interesting over time and they create epic moments that people talk about for years.



Randomness Lets Friends Play Together

I can’t play chess with my friends. I used to play competitively and was one of the best in my state. When my friends and I play chess, I know I’m going to win. They know I’m going to win. This feels boring for me and frustrating for them.

When we play Magic: the Gathering things are completely different. I’ve actually spent even more time studying MTG than I’ve ever spent on Chess. Despite this, the random elements mean that my friends always have a chance of winning. We can enjoy playing together.

Randomness Keeps Players Engaged

While the tension of randomness can sometimes feel unpleasant, having no tension is even worse. Even against an equal opponent, many games can start to feel boring once you’ve won a significant advantage or taken a significant setback. You can either lose hope for victory or any fear of defeat.

Randomness provides an element of uncertainty that can help address this issue. No matter how well I’m doing in MTG, there's almost always a card that my opponent could use to come back. While they might not have it in their hand or deck, I don’t know that for certain. Even while I’m far ahead of my opponent, I focus on looking for ways to minimize my opponent's’ chances of coming back with the right draws. Is there a way I can turn my 90% chance of winning into a 95% chance instead?

Meanwhile, when I’m far behind I’m always looking for ways to maximize the number of chances I have to draw the card that can save me. This keeps me engaged in the game until the very end.

Randomness Can Reward Skill

I know this sounds crazy, but give me a second to explain.

Imagine two math competitions. In the first, there are always the exact same problems with the exact same answers. Anyone can spend a bunch of time memorizing the solutions that skilled mathematicians worked out years ago.


In the second competition the problems are randomly generated by a supercomputer. Some years you might get lucky and get a lot of problems that explore areas of math you know well. Even so, the people that actually understand mathematics get the advantage here. You can’t improve through rote memorization.

You've probably noticed the first competition sounds a lot like Chess. Well designed randomness works like the second competition. When randomness provides a different assortment of cards and considerations each game, the best way to improve your overall performance is through learning the game’s core strategy. It rewards the ability to genuinely analyze the right move.

Randomness Can Increase Strategy

I'm currently working on a digital card game called Faeria (which you should totally check out when it releases). At the moment we’re testing a card called Bold Bargainer. It looks like this:

Bold Bargainer - 6 faeria


When you summon Bold Bargainer, reduce the cost of a random card in your hand by 6 faeria.

3 attack, 3 life


Faeria is the game's core resource. You stockpile it over your turns and use it to play your cards. Playing Bold Bargainer means that a random card in your hand is going to get its cost reduced by 6. This is a huge discount. If you can take full advantage of it, you get a decent creature for free. However, you can't reduce a card's cost below 0. If the Bold Bargainer's ability randomly selects a card in your hand that costs only 1 faeria, you're going to lose a lot of value.

This simple design has deep strategic implications. The first thing it affects is your deck construction. Bold Bargainer is clearly best when everything in your hand costs 6 or more, to ensure that it will hit something you want it to. Cards that cost less than 6 faeria are suddenly significantly worse in your deck than normal. Meanwhile, more expensive cards naturally become more desirable.

But it doesn’t stop there. Bold Bargainer also gives you strategic decisions to make while playing. Because you can't really afford to just run cards that cost 6 or more faeria, you're going to have to include some cheaper cards in your deck. When deciding which cards to play each turn you might want to keep higher cost cards in hand when possible. This will maximize your eventual chances of hitting a good target with Bold Bargainer.

Additionally, getting a hand with absolutely no cards that cost less than 6f, while you also have enough resources to play the Bargainer, can be difficult. You might realize that playing the bargainer before you can ensure its value is actually the best move. Sometimes you need an extra creature on the board right now, or you just have to accept the risks of not reducing the cost of the card you really want.

Now let’s compare it to a version that doesn’t use RNG.

Less Bold Bargainer - 6 faeria

When you summon Less Bold Bargainer, choose a card in your hand. Its cost is reduced by 6 faeria.

3 attack, 3 life

The Less Bold Bargainer doesn’t take much skill to play well. You can put it in just about any deck that has at least a few high cost cards. Just wait until you draw just one to combine with it. You don’t have to think about hand-management nearly as much. Also, when you do have several high-cost cards in hand you’ll just reduce the cost of the one you want to play sooner. That's a decision, but it barely adds anything to the normal decision-making process of what you want to play. Fewer deckbuilding decisions, fewer gameplay decisions, overall a much less skill-intensive card.

Randomness is an Emotional Safety Net

Many players claim they hate RNG, yet keep coming back to games that use it. They’ll often try games that announce they’re removing RNG from the experience, but eventually they’ll wander back to Magic and other games with randomness included.

There’s a pretty simple reason. When someone loses a game of Magic, she can blame her loss on the game’s luck. When she loses a game without RNG, she can only blame herself. Weirdly, players tend to credit their victories to their skill and blame their losses on bad luck. This is a well-documented psychological effect, and it lets people feel better about themselves while playing your game.


In fact, nearly everyone thinks they're above average in a lot of things.. You can find endless studies supporting this. Here's a quote from a relevant article:

"In studies, most people overestimate their IQ. For instance, in a classic 1977 study, 94 percent of professors rated themselves above average relative to their peers. In another study, 32 percent of the employees of a software company said they performed better than 19 out of 20 of their colleagues[...]

[...]Because even the worst driver may by chance avoid an accident, people are more likely to overestimate skills like that than concrete skills like chess or tennis, where the incompetent are trounced quickly."


Randomness Creates Faster Game Flow

In classic tabletop games, random effects usually take longer to resolve than making a choice. If you give +1/+1 to a random friendly creature in a tabletop game you have to assign numbers to all the creatures on the board, get a die and then roll it. If there aren't exactly as many friendly creatures as there are numbers on your dice you might be looking at rolling more than once.


In a digital card game some of these effects are just faster to resolve by having the game take care of it for you. In Faeria we have a card right now that gives +1/+0 to a random friendly creature at the start of each turn. If we allowed the player to select the target, she would have to stop at the start of each turn to micromanage the effect. This can quickly get annoying, especially if you have two or three similar cards out.

Randomness Can Feel Like Christmas



Why is it often more fun to get unknown gifts than to just buy exactly what you want? Because the randomness is all-upside.

When I go look under my Christmas tree and see six presents with my name on them, I don’t know what they’re going to be yet. This is a fun type of suspense, wondering which of several good things is going to happen. Am I going to get that new game I’ve been thinking about? How about that collector’s edition of Calvin and Hobbes? I don’t know what it’s going to be, and it feels great to rip off the wrapper.

Unfortunately, a lot of game designers don’t treat their RNG like Christmas. They treat it like russian roulette. Here’s a design I would never do in a strategy title.

Erratic Efreet - 4 faeria


When you summon Erratic Efreet flip a coin. If tails, destroy it.


Ugh. Just looking at that design makes me want to strangle something. This is the worst kind of RNG, and often the most common among new designers. There is no way for the player to influence it and it creates a simply massive swing in the game results (usually an 8/8 would cost about 8 faeria). If you play it you either get a very cheap creature or you lose a bunch of faeria for nothing. It’s simply awful.

However, I enjoy playing with Hearthstone's Unstable Portal. When you play this card you get a random creature from the entire colleciton added to your hand at a reduced cost. This is the type of all-upside present that feels more like a holiday celebration. You might occassionally be dissapointed with the present you open, but playing the card still feels exciting.

Wrapping Up

Randomness is like dynamite in game design. It’s a powerful tool, but if you aren’t careful it can easily blow up in your face. You also don’t want to strap dynamite onto everything. Random effects do add a lot to the game, but it’s very possible to overdo it. As the design of Faeria progresses we are trying to be very careful when implementing random effects.


The most important thing to understand is that Randomness is still just a tool. It's also not the only way to accomplish a lot of these benefits.


For example, while RNG can create uncertainty that keeps games interesting until the end - you can also create that uncertainty in other ways. Rock, Paper, Scissors doesn't exactly have randomness but the outcome is very similar. You don't know what your opponent is going to play, and thus you always have hope of a comeback if you just guess correctly.


Just don't make the mistake so many new designers make, which is trying to kill randomness just for the sake of killing it. Understand your tools. Learn what their strengths are, why they work in some situations and how designers can mess them up.


In the mean time try to create Christmas, not Russian Roulette.


See you next time.



Design 101: Archives

1 - Design Goals

2 - Complexity vs. Depth
3 - The Structure of Fun

4 - Emotional Alignment

5 - The Role of Randomness

6 - Balancing Games

7 - Playtesting


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