Game design or computer science?

Everything Mark wrote is not only correct it is the all-encompassing answer I have seen for the last decade. He is spot on about the level design stuff, delineating the differences in game design roles, and also telling you that these jobs often blend together (just as they do in other entertainment industries like movies, tv, web design, etc)

My real-world, frank/harsh answer is that you absolutely need to be able to code, and the days of game designers who don't understand object oriented programming are dwindling. Everything I see on the West Coast and Northwest of America has been trending that way for 8+ years. Me personally, just me, I have not seen a game design job not require some code/script knowledge since Halo 3 was launched.

As my former boss said to me, "I can hire a guy with a fantastic idea for a building, or I can hire a guy with pretty good ideas who can also do the wiring, plumbing and won't dream up ideas that we don't have time or money for.
I can't hire both."

I'm going to cite my examples by offering you to take a look at the multitude of game design jobs available at this very second in the Seattle/Bellevue area, San Francisco area (craigslist, gamasutra, LinkedIn, game developers themselves, Publishers like Microsoft, Ubisoft, Big Fish, or bazillions of San Francisco companies),
or simply look at your favorite companies. Do you see a trend of languages like C#, C++, and Javascript? Do you see trends in game engines they need you to know?

That's my bonus tip to you. It's not only coding that you need to know, some jobs require you to learn a game engine (or even 3D artist tools, as Mike mentioned). Do you want to work for Gearbox (Borderlands/Battleborn) or for Valve (Shadows of Mordor)? Then you need to learn how to work in the Unreal engine as well.

At the very least, learning some object oriented language (C#, JS, C++) will help you look at games and game design at a deeper level.
Metaphorically, you will go from someone who can only show the outside design of a car, give you a test drive, and has to ask a mechanic to make changes,
To someone who can open the hood, work with other awesome mechanics, and drive away in a burly tank that used to be a car.

Hey Isaiah,

Whether it's true or not depends on your definition of "game design."

Strictly speaking, game design refers to the creation of game elements like rules, mechanics, and story. You can be a game designer and never develop a video game -- and many board game designers do exactly that.

Probably, you mean you are interested in video game design, but this is still a gray area. Usually, video game design refers to the construction of levels and the authoring of abstract game systems (like combos in a fighting game, or inventory management for a dungeon crawler). Often video game designers are expected to write simple programs called "scripts," but this is not their primary task. Level designers, for example, spend most of their time working in 3D art programs like 3D Studio Max. Systems designers spend a lot of time with spreadsheets, crunching numbers.

Finally, some people say "video game designer" when they really mean "video game programmer." These are the people that actually write the code that makes the computer do what it's supposed to do -- but often, programmers aren't designers. Programmers specialize in understanding the technology required to make games work, but they don't often define the game itself. The typical production model in most modern studios goes something like this:

Game designers come up with the core ideas for the game, then meet with programmers to figure out which ideas are possible. The designers then write design specs and work closely with programmers to create prototypes of the game systems. Once the prototypes are working well enough, the programmers spend time turning the prototypes into final game code and the designers start play balancing the game.

Not all studios run that way, and there aren't always clear cut lines between designers and programmers. For instance, I am a technical designer, which means I usually come up with game ideas, then write most of the code for them myself.

So...to finally answer your question: if you are interested in being a programmer or a technical designer, computer science is a good field of study. It's not the only choice -- I am a self-taught programmer with degrees in Math and Physics -- but it is a good choice, and will prepare you for heavy-duty programming that guys like me don't often do. On the other hand, if you're more interested in creating levels, or the stories for the game, or building sets of rules (like designing your own pen and paper RPG), computer science probably isn't the right fit. Depending on your interests, degrees in digital art (for level design), literature (for story development), or mathematics/economics/game theory (for game systems design) might be better choices.

I see that I'm supposed to cite sources. Hmm... All I can tell you is I've been writing games professionally for more than 20 years, so I've seen a lot. Feel free to ask follow-up questions if what I'm saying makes no sense.

Good luck with your choice! Game development is a blast!