There is a good deal of debate on the value to randomness in game design. Many designers have a snooty idea that randomness is a crutch. Other designers, especially board game designers, will tell you randomness is a key component of a successful, long lasting design.

It’s easy to see randomness everywhere in games. Most board games rely on dice to generate random behaviors. Heck, it’s hard to think of a board game that doesn’t use dice. Video games’ grandaddy, D&D, even made up all kind of new dice to create even more tables of randomness.

Clearly, randomness works. It’s sometimes good and sometimes bad, but why?

I believe that the need of randomness is inversely proportional to the complexity of a system. If the system being simulated is complex enough in itself, it does not need randomness. If the system is not that complex, or perhaps more importantly, if the players inputs to that system are not widely varied, randomness is not only a good idea, but required.

You can take a measure of your game for what I call “situational randomness.” Are there enough inputs and systems in your game that create a hugely wide variety of situations? Will a player’s interactions with these systems have plenty (but not too many) opportunities to create magic moments where all the game elements align just right to create a moment worthy of telling their friends about? And will their interactions with these systems be somewhat unpredictable?

Lots look at some examples. Imagine you have a simple “apple drop” style games. Apples drop, the player catches them. Maybe you do something clever like color the apples and if you catch so many of the same color in a row you get a bonus. In this scenario, the system is not very complex. More importantly, the player has literally no input into the system, just reaction. This game is going to create the opportunity for magic moments (say catching the same color of an apple 5x in a row) through randomness. There really is no other options.

Now imagine another game, lets call it apple battle. It’s a dual sticker shooter where apples attack you from all sides. Your bullets will continue through targets like a laser. If you can shoot 5 red apples in one shot, you get a huge bonus. Here the player has more say on their opportunities. They can move around attacking the apples from many different angles. The apple generation is still random. What could we do to remove the arbitrary randomness?

What if the apples, instead of just disappearing when shot, moved back and exploded with physics, affecting other apples around it, bouncing them around all physics-like? Now this is something the player could interact with many times, and get the different outcomes. You could make the generation of the apples the same patterns, and the outcome of interaction would be different nearly every time. When something really special happened, the player would feel accomplishment. Under this scenario, randomness is probably not needed at all.

Now imagine exploding apple drop was multiplayer. Now you have an unpredictable system with multiple inputs. Now, randomness could be flat out bad. Randomness could greatly benefit one player and punish another. If players have influence over the randomness through, controlling stats that random rolls use, that works.

Board games simply cannot create widely unpredictable systems like this. They need randomness to create the feeling of an unpredictable system. However, video games can easily create simulations of complexity without ever needing random dice rolls.

Situational randomness is relying on players making the right choice, at the right time, in the right situations, perhaps with the right amount of resources, to make magic moments happen. In your game, can players predict the chaos enough, and react quickly and correctly to influence the system as they wish?

Randomness certainly has a place, but recognize when your game does not need it.