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Demarcation - An Objective Metric for Skills in Games
by Enrique Dryere on 12/16/09 07:11:00 pm   Featured Blogs

The following blog post, unless otherwise noted, was written by a member of Gamasutra’s community.
The thoughts and opinions expressed are those of the writer and not Gamasutra or its parent company.


Whether you're hopping around throwing fireballs in Super Mario Bros or World of Warcraft, skills and abilities are at the core of gameplay. They define what we can do within the game, and how we do it.

Skills can take on a number of forms. Determining how successful they are is difficult, because the task is both subjective and case-sensitive. However, I believe that gameplay can be related to language. In a previous article, I suggest that since they are both forms of communication, they rely on clarity to be effective. This has led me to discover an objective metric which I believe is applicable to skills in most types of IDEs (Interactive Digital Entertainment): demarcation.

Demarcation: the clarity with which a skill's effects are separated from other elements of the game.

Good demarcation will increase the perceived effectiveness of a skill and make the gameplay far easier for the player to learn and master. As stated, this does not necessarily apply to every type of IDE or genre. For instance, the effects of "skills" in a simulation may not be immediately clear to the player if it will better resemble reality.

How to Achieve Clear Demarcation

There are primarily three qualities of a skill which determine its demarcation. They are time, multimedia feedback, and potency.


Timing is a key factor of demarcation. For single action skills, this can be as simple as a clear point of execution.

Things become more complicated, however, when duration is introduced. Duration is typical of skills such as "buffs" and area of effect attacks. A single skill may include several phases. For instance, a spell that summons a meteor may have a warning phase in which the targeted ground pulses red, a point of impact which deals direct, area of effect damage, and a burning phase, during which the struck ground continues to burn, dealing damage to any units who pass over it. Regardless of the number of phases in a skill, each phase should have a clear beginning and end.

A skill does not need to be executed the moment the player selects to trigger it, but the time of its execution must be easily predictable. In other words, it must happen when the player expects it to happen. This will increase the perceived responsiveness of the skill.

A good way to bridge the gap between selection and activation is through a cadence or rhythm, which can be established by audio and visual cues.


Multimedia Feedback

Players need some sort of feedback to even realize they're playing a game. The simplest form is likely text. But every word, sound, image, and haptic cue within a game is capable of conveying information to the player.

In order for a skill's cue to work well, it must be easily distinguished from other sounds and images contained within the game. It must be clear and identifiable. But most importantly, it should coincide with the phase of the skill that it represents as closely as possible. Cues can accentuate good beginning and end points or mask fuzzy ones, as may be required when dealing with net code

In addition to a skill's execution, sounds and visual cues may also represent the results of a skill. For instance, whenever a player scores a headshot in an FPS, it can trigger a sound to let them know they've hit their mark. This is typically a higher pitched tone to separate it from the lower pitched noise of a gun.

For the purposes of demarcation, graphics serve primarily as a form of communication. Developing a symbolic language within a game is important. Generally, games will adhere to established paradigms within their genres. Perhaps the simplest example of this is the color-coding of elemental spells in an RPG. Players should not only be able to identify skills with which they are familiar, they should be able to decipher a great deal of information about newly encountered skills from the way they look and sound. This level of order is essential for demarcation to be achieved when things get cluttered in a busy game.



A skill can have a clear beginning and end with excellent cues to represent each of its phases, but what does it do? You can achieve clear demarcation with just timing and feedback. For instance, you can create a skill that displays the damage generated by the next attack in much larger, bolder numbers. Players know they've used the skill, and yet it may do nothing relevant to the gameplay. However, if the attack were also to do extra damage, it would be set even further apart from the normal flow of the game. Therefore, potency is also a quality of demarcation -- and one which becomes increasingly important as the capacity for audio and visual cues diminishes.

How much potency is sufficient? If a player has to check for a little icon by their name to make sure a buff is active, it's probably not potent enough. Or another classic example: Power Swing adds 5 points of damage to a player's next attack, but her normal attack damage can vary from 10 - 20. She swing once, deals 18 damage, and use Power Swing, and deals 12 + 5 = 17 damage. Unless the skill is backed by strong multimedia feedback, the timing could be flawless, yet the skill would have very poor demarcation. And yet if it is accompanied by loud sounds and flashy graphics while proving ineffectual, the iconography in the game loses credibility.

Perhaps it would be more effective to slow a player's attack by a percentage and ensure they deal maximum damage so that Power Swing will always deal more than their normal attacks. If done correctly, this wouldn't affect the mathematical potency of the skill, yet it could increase its perceived potency.


A Gray Area

Unfortunately, in order to determine the pure "potency" of a skill, it must be compared to other similar skills and effects within the context of the game. Trying to determine the potency of a skill without a point of reference is typically not possible. Even then, there is more to potency than big numbers, as not all abilities simply deal damage. The more complex the skill, the harder its effectiveness is to judge.

Often times, creating a successful skill can become a balancing act between applicability and uniqueness. A skill will stand out more if it is unlike any other in the game and/or is not used often. Yet the effectiveness of the skill will seem greater if it is applicable in nearly any situation. How potent is a skill that holds an opponent in place? It's powerful in a race, but it's useless if the opponent wasn't planning on moving. Not only is this subjective, it's extremely case-sensitive.


Other Facets of Successful Skills

Clearly there's more that goes into making a successful skill than just demarcation.

Applicability - How often is the skill useful?

Creating highly specific skills may give the player too much to worry about and insufficient exposure to their given abilities.

Expediency - Does the skill fit the game and is the reasoning behind it sound?

It may seem crazy that an Italian plumber is suddenly spitting fireballs, but it fits the tone of the game and introduces a new dimension to gameplay.

Uniqueness - Is the skill different enough to stand out from others, and how often is it used?

The uniqueness of a skill can enhance its demarcation, but often comes at the expense of applicability. Still, it is quite possible to have a commonly used skill that is unlike any other in the game, particularly if the game only features a small set of skills.

Balance - Is the skill proportionately useful in comparison to other skills in the game?

This is particularly important in competitive games, whether they be multiplayer or single-player. For all the work you may put into a game, it can be eclipsed by a single skill or strategy if it unequivocally proves the most fruitful, as players are forced to employ it in order to maximize their efficiency.

Synergy - How does the skill interact and affect other skills?

This is a crucial question for developing complex gameplay. The synergy between two skills doesn't have to be explicitly stated by the game. For instance, simply jumping and spitting a fireball in Super Mario Bros. can be considered a form of a combo-skill. Without the cooperation between these two abilities, it may have been impossible for players to defeat certain enemies over obstacles.


I find that these are all fine questions to ask when creating skills, but I always consider its demarcation. What approach do you take to guarantee the quality of skills in your games? Or by what criteria do you judge skills to be successful? I would love to gain insight into other people's processes.

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Mark Venturelli
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I'm sorry, maybe I just didn't get it, but you seem all over the map. What are you exactly trying to define with "skill demarcation"? Can you define a little better what you consider a "skill"? Why are "skills" any different than any other game mechanic? What can we hope to achieve by viewing them under specific lens?

Luis Guimaraes
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This whole post remembered me of Battlefield Heroes, Unreal Tournament, Metal Warriors and Yugi-Oh. All these features variety of skills with different applications and effectiveness.

Apart from that, I think a good solution (and I didn't have yet the opportunity to proven the concept) for the Facets of Successful Skills, beyond pure good game design choices, is that used in Tony Hawks skate games: big offer, loew value. In other words, everytime you use the same skill or strategy again, it had less value for the overall score.

Of course Tony Hawks games are all about variety and combos of tricks and maneuvers. But that's not that hard to put in other kinds of games, that "one never falls in the same trick twice". Well, "never" and "twice" maybe too hard-minded, but I'm sure something around can be done aswell, with the same player/adversary getting resistence everytime he's target of the same skill, or the most bought items raise prices. It's telling the player to avoid the individual and collective "same".

Enrique Dryere
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Certainly. While coming up with a proper definition is probably a subject for a whole other essay, for these purposes let us say that a skill is a game mechanic which is purposefully activated by the player. Of course, NPCs can use skills as well, but there the definition becomes more complicated.

The purpose of establishing a metric by which skills can be measured is ultimately to produce better skills.

Demarcation, as stated in the article, is basically how "clearly the skill is set apart from other facets of the game." It could be applied to other aspects of game mechanics, though I believe it is most important for skills.

This view on skills is predominantly based on action/adventure, roleplaying, strategy, fighting, and FPS games. It is less applicable to other genres.

Enrique Dryere
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@ Luis

Reducing the potency of skills/abilities if they are overused is a decent way of getting the player to use different skills. It's a particularly good fit for a game like Tony Hawk, since the sport it approximates rewards variety. However, this strategy is also employed in MMOs, like WoW's diminishing returns. I think it's a bit less successful there, yet still effective.

David Wipperfurth
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I enjoyed this article thoroughly, and basically agreed with everything in it. I have a few comments that may or may not be useful.

At the beginning of the article I was confused by your use of the term 'skill', because it is often used the define the players mastery of the game or game elements. Also, Avatars and NPC's don't technically have skill since they aren't sentient. When they are said to have skills it is through the use of personification. Re-use of words in common when talking about gaming topics, so it's not a big deal or anything, but it did bog-down my read until I understood your meaning. A word substitue might be less confusing, like 'ability' for example might be less confusing.

I agreed with everything you said, BUT you gave no proof of ANYTHING you said, so if I disagreed I would still disagree right now. I wouldn't expect an article like this to be backed by case study, of course, but I do think with these kinds of ludological essays, anecdotal evidence can go a long way. Plus it is pretty easy to quote game mechanics from popular games in examples.

My last thing is, this really isn't objective, since you don't define how each of the aspects listed should be measured. In fact, you even discuss a bit about the difficulties of measuring them objectively. It is clear that these mechanics need to be measured within the context of the game they are being developed for, but I think you could get this approach to an objective state if you suggest a way to develop a base-line demarcation level for a game, and then suggest a way to evaluate a demarcation compared to the base-line with some scales or value systems. Even if the evaluation system is: rate the potency on a scale of 1 to 10, 1 being the weakest ability in your game, and 10 being the most powerful ability in your game. That's still much closer to objective analysis, you know.

I look forward to reading more from you.

p.s. those links gave me 404 errors.

Enrique Dryere
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Thanks for the comment (fixed the links).

I can see how the term "skill" would be confusing, and defining it properly so that it fits any genre is rather difficult. I should probably favor the term "ability" in the future.

I tried to make this article a bit lighter reading, since I am still developing the concept of Demarcation. That is why I strayed away from too many details, but you're right: I think some more anecdotal examples could have helped.

Applying true metrics as you suggested to the qualities of demarcation is relatively easy for time and potency. For time, it could simply be a measurement of delay from activation, duration, and predictability (how much variance exists in the moment the ability will be executed).

And potency can be done just as you mentioned. If we were measuring movement abilities and the first moves a player 5 units and the second moves the player 10 units, then their respective Potency would be 5 and 10.

Multimedia cues are a bit harder to quantify in this fashion. You can somewhat objectively ask whether the tone stands out (due to frequency, intensity, or timbre), whether the visual representation is unique enough, visible enough, and intelligible (if it corresponds to established paradigms so that players can quickly understand what the ability does).

However, abilities in games can get more complicated than this, and a uniform measurement system may not be possible. The same numbers that apply for an RTS don't apply to a turn-based game's Timing.

Not all abilities in games will be as simple as moving X amount of spaces. A great example of potency that is hard to quantify can be found in WoW. There are instant cast spells and spells that take 1.5 seconds to cast. Since there is a ~1.5 second global cooldown, once the player casts the instant spell, they cannot cast again until the 1.5 second cast time spell would have been finished. This means that, spell haste aside, the only advantage an instant cast has over a spell with a 1.5 second cast time is that it will be executed first (before the global cooldown). If the spell is simply doing damage, this advantage may not be very important in many PVE encounters. Yet in PVP, where player must remain on the move and react quickly, instant casts are a huge advantage. How do you quantify the difference in potency between these two abilities if they deal the same damage?

Thanks again for your input!

Luis Guimaraes
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@Enrique Dryere

"How do you quantify the difference in potency between these two abilities if they deal the same damage?"

I think only the players with experience on the game can tell it. For exemple, maybe both skills considered alone will make the instant one be better for the designer calculating it. But, if you consider both combined, than strategical differences arise:

1.5sec + instant = 1.5sec to attack first, damage*2

instant + 1.5sec = damage*1, 1.5sec to attack first or heal, damage*1

The opportunity for healing between the attacks can be the difference between life or death, specially when the adversary damages and delays, and the combat situation come into the equation. Of course level is the real difference in MMORPGs, but players always find a way.

Glenn Storm
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@Enrique: I really like 'demarcation' as a concept to keep in mind with regard to player feedback, when you're talking about UI design; feedback on controls and game mechanics. Like David W., I was thrown a bit by 'skill', but I'd probably have been equally thrown by 'ability' unless the word 'avatar' was added to differentiate from player skill and player ability. The comment discussion on metrics is a can of worms to me. I can image a couple avatar abilities off the top of my head that would flat out defy measurement; at least, defy it in a way that comparison would be difficult at best. (night vision ability in a FPS, freeze monster ability from a powerup in a platformer, G.E.C.K. from F3) Rather than solely looking for numbers to evaluate a particular avatar ability, I'd take a cue from Jesse Schell, author of The Art of Game Design: A Book of Lenses, and apply the concepts of demarcation, potency, etc. as Lenses; guides that simply help the designer to focus on the concepts when viewing the avatar ability and present particular questions related to those concepts. Sort of like a heuristic, but a bit more flexible to my eye. I think measurement is great, but if you can't dispel the idea that you're comparing apples to donuts, you'll have a hard time selling the measurements as valid imho. By contrast, a Lens can highlight important aspects of the subject being focused on, allowing for a clearer comparison or critique; if qualitative rather than quantitative. Great post!

Enrique Dryere
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@ Luis

The instant cast spell is obviously better than the one with a 1.5 second cast time. It would take an external influence, like another ability or item that grants increased regeneration while casting, to make a spell with a cast time compete with an instant cast.

However, the difference in potency between the two spells changes depending on the situation. In a long raid fight in which the character simply stands around casting at an immobile enemy, the instant cast is only marginally better, while in the thick of PVP the difference can be quite drastic.

You can set up an arbitrary value based on research and testing that averages out an instant cast's potency, but that means that the spell will be valued too low or too high in certain situations. This isn't necessarily a bad thing, as it will encourage players to change their strategies to overcome various encounters, but it can be a very tricky balancing act.


Thanks for the comment Glenn, I always enjoy them. I'll definitely check out the book you recommended, sounds very interesting.

Those are some particularly interesting skills that you list. I just finished playing Dragon Age: Origins last week, and without its "Battle Pause" game mechanic, I doubt I would have ever gotten through it. Abilities like these defy comparisons in potency to other "abilities" in the game, but they can still have clear beginnings, predictability, durations, and feedback. The pause happened the moment I pressed my button and lasted until I pressed it again without fail. For feedback, there was a plaque that read "Paused" across the top of my screen and everything was still, making it very easy to know that the ability had been used and what it does upon first using it. This makes for good demarcation as I see it.

However, its potency is much harder to assess. I would say that it is 100% effective in accomplishing what it's meant to do. Technically, it could be more powerful, allowing you to move and execute other abilities while the enemies are frozen, but that would simply break the game, considering it can be done at any time without cost.