A version of this article first appeared in the October 2008 issue of Game Developer magazine.

Sid Meier once said that games are a “series of interesting choices”.   I’ve always liked this definition – it speaks well to what is unique about our craft.  For all of the progress that we’ve made in graphics, audio, physics, AI, and storytelling, interactivity remains the defining feature of our genre.  And interactivity, when you think about it, just means ‘your decisions matter’.

In this light, the true job definition of the game designer becomes clear: we are tasked with creating these interesting choices.  So what makes decisions engaging?  Understanding this has the capacity to turn a shallow game experience into a deep and engaging one.

Opportunity Costs

Businesses and economists use a term called ‘opportunity cost’ to help describe what any given business opportunity will prevent them from pursuing.  By putting your money in the stock market, you sacrifice guaranteed interest you could earn from the bank.  By promoting the iPod, Apple committed resources that could otherwise have spent selling Apple Computers.  By nominating Obama, the Democrats chose not to run Hillary.

Whether or not these were the right decisions was almost impossible to tell at the moment the decision is made.  The iPod decision seems like a no-brainer now, but at the time, it represented a significant shift for Apple, and there were doubtlessly some sleepless nights over it.  What’s lost is that some of these decisions are equally as hard to examine in retrospect.  If Obama loses his presidential bid, we’ll never know if a Clinton run would have done better.  Whenever this kind of second guessing afterwards occurs, you’re almost guaranteed that the original decision was interesting.

Games make players factor in all manner of resources as costs.  The most obvious are direct analogs – wood or steel in an RTS.  But the most common resource used is time.  In Civilization, turns your city spends building archers is time you cannot spend building a temple.  In Mortal Kombat, the time you spend doing a leg sweep is time you cannot do a flying kick.  The two choices are mutually exclusive, and both have a chance to be the better choice.

Designers of mature game properties tend to have extremely sophisticated ideas of what is a resource in their games.  World of Warcraft’s designers now treat each party slot as a resource.  If your raid needs a healer, you can bring either a shaman for great group healing or a paladin for optimal single-target healing.  Or you can bring both, at the sacrifice of one player that can deal damage.

Magic: the Gathering’s designers are perhaps the best in the industry at this kind of analysis, and adding new ways to consider cards resources.  Not satisfied with the resources found in the original game (turns, mana, cards in hand), over time they have experimented with cards which manipulated resources like the graveyard pile, and accentuated other key resources such as turn tempo .  One mechanic called madness makes cards cheaper to cast if they are in the process of being discarded. Normally, discarding is a negative, but this mechanic turns discard opportunities into a valuable resource to build whole decks around.

Meaningful Choices

An interesting choice is a meaningful one, which means that there must be some sort of appreciable differences between the two choices.  If, in a boxing game, the left jab and the right cross have the same timing and do the same damage, the difference between the two is negligible, and the choice is immediately uninteresting.

Dozens of games ship without many meaningful choices – these games may be fun short-term diversions, but they are rarely considered deep or interesting.  Most story in games is extremely linear – some may let players make dialogue options, but in most cases the conversation will end in the same place.

At BioWare, we take great pride in our interactive storytelling.  We work hard to make sure that the choices a player does make has an impact on their character, their companions, and the world around them.  To us, that choice and its consequences are what interactive means.

Bad Choices

It would be nice if, in all cases, you could have two equally valid but strongly different choices, but in most cases, offering meaningful choices implies the player can make a bad one.  That’s okay -that chance is what makes the choice meaningful.  On the other hand, if a given play is always a bad choice – i.e. there are no circumstances where it’s the best choice – you’re probably looking at something you can cut.

But factor in the hidden payoffs.  Throwing someone in Soul Caliber is slow and leaves you exposed – mathematically it’s almost always a bad move – but is deliciously humiliatingly if you manage to pull it off.  Killing someone with a chainsaw in Doom often seems nigh impossible but pulling it off even one time in ten is well worth it.

The Role of Information

Players can only make good decisions if they have good information available to them.  If you know your opponent is susceptible to fire damage, you can sling fireballs at him instead of magic missiles.  Even simple decisions like this makes the player feel like a genius.

Chess is a good example of a game that offers perfect information – both players are completely aware of the capabilities of the other player.  The game is highly tactical – it is, in fact, all tactics. Other multiplayer games tend to offer imperfect information to give players tactical clues. Soul Caliber players judge your capabilities based on your chosen character, and Magic: the Gathering players judge it based on untapped land.

In the endless debate of class vs. skill-based systems in MMOs, one rarely mentioned advantage of classes is that, in PvP, they give you some idea of your opponent’s capabilities, allowing you to form a strategy to deal with them. Skill-based fans argue that the surprise factor is part of the allure of the system, but I disagree.  When players have no information to base a decision on, they revert to what works the majority of the time.  Lack of information tends to narrow tactics, not expand them.

Most designers try too hard to hide information.  The recent popularity of poker can be tied pretty firmly to the ascendance of Texas Hold‘Em, a game that exposes enough information for players to make tactical choices.

Choosing to Abstain

Sometimes, the right move is not to play.  Examples include blocking and waiting to apply countermoves in a fighting game, keeping your first Warrior in your Civilization city rather than exploring, or leaving mana untapped in Magic: the Gathering for a counterspell.  In World of Warcraft, rogues have the option of going all-out on damage, or leaving just a little energy in reserve in order to interrupt a spell cast.  Choosing to not play is usually a defensive move, an act of biding one’s time and being opportunistic.

These decisions are often interesting, but the designer needs to be careful with them.  As Mark Rosewater, head designer of Magic: the Gathering observed in a recent column, it’s always more fun to play cards than not play cards.  Designers also need to be wary of making defensive measures too narrow – if a counterspell only works 1 time in 20, most players will simply blast through with strategies that are more universal.

Sacrificial Choices

In the game show Deal or No Deal, contestants decide between a cash amount the producers offer, or opening another suitcase which may cause that cash amount to (hopefully) go up or (more likely) go down.  Academic economists love this show, and so should game designers: the bird-in-hand choices are mesmerizing, and yet statistically the contestants so often make the wrong choice.  Which, of course, makes great TV.

Consider 5 card draw.  In order to attempt to improve your hand, you must first discard.  There is no guarantee that your new card will be an improvement, and in some cases, you may be bluffed into breaking up a pair to chase an unlikely straight.

Such mechanics are very powerful but tough to balance.  Casual players typically love them, but the effects of the choice need to be significant enough to lure them to not play it safe.  Conversely, hardcore players learn quickly how to play the odds.  If the payoff isn’t big enough or the odds too unlikely, the mechanic will rarely be used.   If it’s too advantageous or easy to manipulate into happening, your hardcore will dominate with it.

Broken Mechanics

With this choice-centric view of design, identifying broken mechanics becomes easy – they are those that effectively reduce choice.  In Magic’s “Betrayers of Kamigawa” expansion, one card, Umezawa’s Jitte, was so overpowered that nearly every tournament deck either used it or packed cards to deal with it.   In a game that normally encourages creative deckbuilding, the environment suddenly became frustrating and confining.  The card was broken.

Sometimes, it’s hard to tell.  In MMOs, players constantly complain about classes being broken – that certain classes are the best PvPers (and therefore everyone must react to them) or the best healer to bring to a raid (so why would you need anything else?).  It can be hard for designers to tell when a mechanic is actually broken.  Often, the advantage is overblown.  Sometimes, it just takes a while for good counterstrategies to emerge.  Sometimes, it’s best just to wait.  But if you’re wrong, you’ll hear about it.

In Conclusion

I’ve heard some designers and producers try to argue that games should have no bad choices – that players should always feel rewarded, no matter what.    That the whole experience should lead players down a safe, candy-coated path of guaranteed success.

I disagree – certainly, bad choices should not be humiliating or irrevocable, and no choice should make the player quit. But choice is the very essence of interactive gameplay .  While bad choices may frustrate the player, good choices will reward him, making him feel clever and engages.  And interesting choices will leave him talking, and make him want to replay the game to try the other path.

To me, the choice is simple – what’s yours?