[MUD-Dev] Character Attributes in Role-Playing Games

J C Lawrence claw at kanga.nu
Tue Jun 11 22:33:18 New Zealand Standard Time 2002


From:

  http://hiddenway.tripod.com/articles/attrib.html

An essay by Bob Hall

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This write-up is my attempt to explore one of the fundamentals of
character design within a role-playing game system. Naturally, your
opinion is likely to differ from mine on this subject, and I hardly
pretend to write a treatise on the matter. Instead, my hope is to
provide some food for thought by writing an editorial on the subject. At
the end of the article, I put my words into practice by designing a
character attribute system.

What are Attributes?

At the most fundamental level, Role-Playing games allow a group of
players to assume the role of individuals within an alternate game world
created and/or managed by the Game Master (GM). While such a character
could easily be played completely free-form - much as a game of "make
believe" is played by children - creating a more believable figure
requires a set of rules to model actions and behavior of the characters
and other figures in the story.

Most role-playing systems use a standardized set of numerical values
that describe the relative capabilities of a creature. Rather than
making an arbitrary decision about the outcome, the GM can use these
value ratings, along with the procedures described in the rules, to
evaluate the result of an event. The outcome, hopefully, is a consistent
world physics that gives the players a reasonable chance to determine
the odds of any action being successful. As a result, this allows
realistic decisions to be made from the point of view of the character.

Now, at some point in the game design process, a decision is made
concerning the level of detail at which a character is to be
modelled. The designer must make a strategic trade-off between the ease
of game play and the accuracy of the model. An elegant game design will
provide a good balance between these contrary aspects, allowing
relatively easy evaluation of events and simplicity of character design,
while providing consistent and realistic results under most
circumstances.

The best possible model of a character would use a huge number of
parameters, and an immense set of formulae, to evaluate the outcome of
every possible event. Of course, such an exact model would require
computing resources beyond anything the human race is likely to acquire
in the immediate future, never mind the lone GM with only a set of dice
and a simple pocket calculator.

To simplify our model to the point where it becomes useful requires
repeated application of the 80-20 rule: 80% of the cases are handled by
a simpler model, and the remaining 20% are dealt with by special cases,
or via a judgement call by the GM.

The ultimate result of this character model simplification process
produces a core set of parameters known as Attributes. (Several game
systems also refer to these as Characteristics or Stats.) Efficient
application of these Attributes to a game model requires that they be as
independent as possible, and for the combined set to be significant
factors in the outcome of almost all random events. Here again, the
designer must make a trade off in the number of attributes required -
fewer for simplicity, or more for better modelling. Because this limited
set of parameters can never possibly be used to model every event with a
reasonable level of accuracy, further supplemental values will still be
needed. So most designers settle for a simple set of primary attributes
that are applicable to the large majority of game situations.

If the type of game world is restricted in some fashion, perhaps by
limiting the types of characters that can be played, then some of the
attributes can be specially tailored to fit the system, and
inconsequential values eliminated. (An example of this might be the
elimination of a psionic or magical aptitude rating in a mundane game
world.) Likewise, multi-genre systems that need to cover a wider variety
of game worlds will need more attributes. A typical solution is to
create a set of universal primary attributes, then add a set of optional
and/or derived attributes that leverage off the primary attributes.

Finally, the question arises about the difference between Attributes,
Derived Attributes, Abilities, Skills, and other character quantifiers
used in the game. An Attribute is a numerical value which rates a
fundamental facet of a characters physiological or psychological
makeup. Derived Attributes, such as Movement and Fatigue, are computed
from one or more Attributes plus a possible modifier, and are used as a
convenience factor during oft repeated game activities. Next, an Ability
is a specific talent that only certain characters can perform (or at
least use with some degree of facility.) Skills are abilities that are
acquired through training and experience.

Attribute Value Range

The next step in the design process is to choose a range of allowed
values for the aattribute ratings. (Note that some recent experiments in
free-form role-playing systems have investigated the elimination of
numerical values for Attributes, and instead employ descriptive
terminology. This method is particularly suitable for a story-telling
style of play, where the emphasis is on role-playing and atmosphere,
rather than closely modelling a game world. While such a gaming style
has its proponents, and may even be a more enjoyable experience for some
(given a suitably skilled and fair GM) it won't be examining any further
in this essay.)

As the attributes are going to be used for evaluating most random
events, it is important that their values can be easily compared to the
results of the random result generator, whether it be a handful of dice
or a deck of cards. In addition, to make the event models easy to
evaluate, multiples of the attribute ratings should also lie within
range of the available random results. (It being quicker and easier to
multiply an attribute by a small integer than it is to divide.)

As the number of regular dice shapes is typically limited to 4, 6, 8,
10, 12, and 20-sided, this restricts the attribute range from one to
twenty for most dice-based systems, unless percentile dice are
used. Even in the later case, attributes below 25 are relatively easy to
multiply by an integer of four or less, then compare to a 1d100 dice
roll.

Of the possible outcomes of all random events in a game situation, odds
close to 50% are the most likely to occur, so it makes sense that the
average result of the random dice roll should match the average
attribute of a typical member of the population. Also, since it is far
easier to play the role of a being with whom you are familiar, the game
systems typically treat a human as the norm against which all else is
compared.

Conveniently, a roll of three six-sided dice, two ten-sided dice, or a
single twenty-sided dice, is 50% successful on a ten or less. Hence a
baseline human attribute value of 10 is commonly used in role-playing
systems. (Besides, as we all know, 10 is a very natural number for a
human.)

Now that the average attribute score has been established, we also need
to determine the distribution of the attribute about the mean for the
general population. This will allow the characters to compare themselves
to others of their kind, and will provide a measure for determining how
many members of the population would be successful at any particular
activity.

Fortunately, assuming you believe in genetics and natural selection,
nature provides a convenient mechanism for building such a
distribution. Since the population attributes are the end result of an
immense series of random events (both genetic and environmental) the
distribution for most numerical attributes will form the classic,
bell-shaped Gaussian curve. (Examples of such a distribution would be
the scatter of missiles thrown at a target, or the scores of a class of
students on a lengthy test.) The peak of this symmetrical curve matches
the mean attribute score, and range should be selected so that the large
majority of the population falls between the minimum and maximum values.

As the sum of a large number of dice rolls has a distribution which is
very similar to a Gaussian curve, such an attribute distribution becomes
relatively easy to replicate by the GM. Realistically, the best fit to a
(truncated) 20 point Gaussian curve would use a large number of random
events, such as 20 coin tosses with a 'head' being a one, and a 'tail'
equal to zero. In reality, however, six-sided dice are easier to toss
and commonly available, so the sum of three six-sided dice is typically
used.

On the other hand, a bell-shaped distribution of attributes tends to
produce a clustering effect about the mean that will reduce the amount
differentiation between two similar individuals. Which of two characters
with an attribute score of 10 is better? In real life, given a
sufficiently large number of repetitions, the slightly better individual
would eventually prevail. Not so in this limited model. (A
percentage-based distribution of attributes has an advantage in this
respect, as no two individuals are likely to have the same rating.)

Other systems use varied scales for the different attributes, allowing
better differentiation between values that are more likely to be
compared. However, this 'refinement' has the disadvantage of adding
complexity to the system - making evaluation of an event different
depending on the type of attribute used. For the sake of simplicity, it
is preferable to use a common scale for all attributes, and vary the
models used to evaluate the outcome.

It should be pointed out that unless the character is being selected as
a random member of the general population, the distribution of
attributes should have very little bearing on the character building
process. For the sake of game balance, the GM may choose to restrict
attributes to a specific range, but otherwise the player should be
allowed to choose attributes that create a character to fill a role,
rather than being forced to fit a role to a character. This liberating
design factor is what separates true, point-based character systems from
the older, random character generation methods.

Categories of Attributes

Now that a numerical range has been established, the types of attributes
need to be selected. While it might be possible to select an optimal set
of attributes that most closely model the greatest number of events, in
reality the attributes are selected to match our real-world
perceptions. Thus, attributes like physical strength and intelligence
are used, rather than, say, the fat-to-muscle ratio or pattern
recognition capability.

At the lowest possible level, most systems assign separate attributes
for our ability to plan and to execute actions - that is, between our
mental and physical capabilities. These gross attributes are then
further divided by the manner in which we mentally conceptualize our
environment - using a fuzzy scale of time, distance, and mass. The
distance factor is characterized by our ability to perform work, either
by physical strength or mental intelligence. Likewise, the time scale
yields the speed and/or acceleration with which we get from result A to
result B, usually described by our reaction rate and dexterity. Finally,
mass gives us our inertia, or resistance to rapid change - as
represented by health and willpower.

In reality, of course, these factors are interrelated, and would be
better modelled using physics and psychology. But we usually choose to
select the attributes that more closely resemble our mental evaluation
process.

Another major group of attributes describes how we interact
socially. Physically, this is usually described by an appearance rating
that is a measure of how close an individual conforms to a beauty
standard agreed upon by a majority of the character's race (and
culture.) Mentally, the selection of an equivalent attribute is more
difficult, as there is a wide range of possible social interactions,
such as leadership or comradery. In practical game terms, however, the
most likely form of interaction will be an obvious or concealed attempt
at verbal manipulation toward some end. This manipulation can range from
bartering with a merchant to an attempt to rally demoralized troops.

The types of attributes just covered will successfully apply to a large
majority of game situations. However, there are certain role-playing
genre that focus on unusual types of actions or events. These
specialized games will usually include one or more specialized
attributes to cover these cases. Examples include a magical aptitude
rating, an insanity level, or a psionic ability score. As these types of
attributes are typically narrowly focused, multi-genre games will
usually treat these as advantages or disadvantages, then apply a special
set of rules to model their effects.

Finally, since there are likely to be more life forms than just humans
included in the game, the attributes must scale well to the other
creature types. The attributes may need to be applicable to
human-to-creature, creature-to-creature, human-to-superhuman, and many
other possible interactions. Linear attribute scales do not readily
adapt to wide ranges of creature sizes and capabilities, nor to
significant differences in technology level or magic capabilities. Thus,
exponential scaling techniques are often adopted in some fashion by many
role-playing systems. While improving scaling ability, such non-linear
attributes provide their own set of problems in terms of realism, ease
of play, event evaluation, and game balance.

Primary Qualities for Attributes

To summarize, here are the primary qualities that I consider to form a
good, flexible set of attributes:

    - Attributes are clearly differentiated from each other

    - Each has a significant effect on the outcome of many events

    - Attribute group is large enough to provide necessary level of
    realism

    - Smallest possible attribute group needed to evaluate large
    majority of events

    - Range of values is comparable to type of dice available

    - Value range is the same for different attributes

    - Values are diverse enough to distinguish between similar
    individuals

    - Attribute types match how we perceive and evaluate others

    - Applicable to the specific game genre being modelled

    - The attributes scale to a wide range of creature types

    - Readily convertible to common derived attributes

Of course, compromises will always need to be made to maintain the goals
of the game design. No system is going to meet all of these objectives,
so priorities need to be established. Game balance also needs to be
taken into consideration, so the attribute generation method will have
to be carefully chosen to prevent abuse by power gamers.

A Look at Some Existing Systems

What follows is a look at the attribute systems used in a number of
common role-playing systems. Many other available games are highly
derivative, so the comments can easily apply to systems outside this
list.

  Advanced Dungeons & Dragons, 1977 - By all accounts the most widely
  played role-playing system, AD&D has both the distinction and
  disadvantage of being derived from the first RPG ever produced. The
  game system is relatively easy to learn, although quirky and
  unrealistic even within the realm of a fantasy setting.
  
  The standard characteristics for a normal human are generated by
  rolling 3 six-sided dice, resulting in a range of 3-18, with an
  average score of 10.5. This makes most event evaluation relatively
  easy, requiring either a 3d6 or 1d20 dice rolls. The set of attributes
  is compact, useful and easy for most players to understand.
  
  The physical attributes are Strength, Dexterity, and Constitution,
  while the mental attributes are Intelligence, Wisdom, and
  Charisma. The creature and magic scaling issue is handled, somewhat,
  by providing an exponentially increasing weight allowance for the
  strength attribute, and offloading a variety of other effects to an
  artificial parameter known as the character level, or number of hit
  dice. (This level/hit dice is equivalent to an exponentially
  increasing experience point total.)
  
  There is no built-in mechanism for improving attributes, other than
  via artificial means. Magical proficiency is directly tied to the
  attribute scores, so theoretically there are few incompetent Wizards
  or foolish Priests. Finally, characteristics close to the average
  provide little character differentiation, especially since the
  resulting adjustments are often grouped by twos or threes within the
  players handbook.
  
  Creatures, or Monsters as they are referred to within the game rules,
  are generated by an entirely different mechanism. For non-humanoids,
  the available attributes for monsters are: Intelligence, Morale, Hit
  Dice, Movement, and Size. While allowing opponents to be created
  relatively easily, this restricted attributes list has the
  disadvantage of making non-combat events more difficult to
  evaluate. Role-playing with non-humanoids becomes entirely dependent
  on text descriptions and the imagination of the GM.
  
  RuneQuest, 1978 - Another random attribute generation system,
  RuneQuest is notable for introducing the concept of skills-based
  characters. The physical characteristics are Strength, Constitution,
  Size, Dexterity and Appearance. Mental characteristics are limited to
  Intelligence and Power. All player character attributes are generated
  by a 3d6 roll, save for Size and Intelligence which use 2d6+6.
  
  RuneQuest employs the concept of derived attributes, which are simple
  mathematical constructs using linear combinations of the
  characteristics. Thus, the number of Magic Points is equal to Power;
  Fatigue is the sum of Strength plus Constitution; Hit Points are Size
  plus Constitution; etc. These attributes are used within the game for
  modelling common events.
  
  The creature scaling problem is handled (somewhat) by the use of a
  separate Size characteristic. However, if they were being used
  realistically, the Strength and Size characteristics are not truly
  independent. (A Strength 10 human would be normal, while a Strength 10
  Storm Giant would probably be immobile.) This issue is handled by
  means a random attribute generation table for each creature, with
  resulting limits on the attribute range. Using a random attribute for
  every creature characteristic in this manner can make the GM's life a
  tad tedious, however.
  
  A notable aspect of this ability system is the complete lack of the
  psychological measure of a being. The lack of advantages or
  disadvantages only aggravates this missing dimension, and tends to
  gives creatures the appearance of an automaton. However, a well-run
  campaign can actually use this to advantage, allowing the players to
  role-play the mental state of their character. This does make events
  based on emotion, or mental resilience, more difficult for the GM to
  evaluate, however.
  
  DragonQuest, 1980 - Produced by the premier wargaming company of its
  time, the DQ fantasy game system gave a much needed rigor to
  role-playing rules, especially in the realm of tactical combat. While
  only partially a skills-based system, DQ did introduce many novel
  concepts to role-playing, such as colleges of magic and weapon damage
  categories. The character generation system for DQ introduces the idea
  of spending points to determine the attribute ratings, although the
  total points are still generated randomly. (For game balance purposes,
  some quirky limits are placed on the maximum attribute rating,
  depending on the point total rolled.)
  
  Physical attributes consist of Physical Strength, Manual Dexterity,
  Agility, Endurance, and Physical Beauty. For mental attributes, the
  character only has Willpower and Perception. Some interesting design
  decisions were obviously made, as there are no Intelligence or
  Leadership ratings, and the physical speed is separated into Manual
  Dexterity and Agility attributes. A Magic Aptitude attribute is also
  included, due to the fantasy-oriented nature of the game.
  
  For a typical character, the average attribute rating will be 15, with
  an absolute minimum of 5 and a potential maximum of 25. Percentile
  dice are used to resolve random events, allowing the attributes to be
  multiplied by an appropriate integer - depending on the difficulty of
  the task. There is no differentiation between the standard attributes
  in terms of points - all cost the same amount to allocate. However,
  the standard attributes are reasonably well balanced in terms of game
  influence, especially since Dexterity has been split into Manual
  Dexterity and Agility. Attributes can also be improved through
  experience, although the price is steep.
  
  Creatures are listed with a full set of attributes, although the
  values are randomly generated - making the GM's life more
  difficult. The only scaling is by means of an escalating point cost
  for skills - the attributes are all linear. However, for the limited
  scope of the genre, this is not a significant factor. The relatively
  small size of the attribute range, compared to the standard 1d100
  dice, allows even large fantasy beasts to be modelled reasonably
  well. Likewise, the lower limit of 5 for human attributes leaves some
  room for quantifying diminutive creatures.
  
  Spell casting is based upon the caster's Magic Aptitude, with some
  modifiers for Willpower (depending on the college.) This allows a
  fairly flexible design of magic-using characters, without the
  mental-based attribute limitations of AD&D. The use of multiple
  colleges is forbidden, however, a nod toward class-based characters.
  
  Palladium, 1983 - All attributes in this class-based system are
  determined by rolling a number of six-sided dice for each
  attribute. The distribution is skewed, however, by the addition of a
  fourth dice when a natural 17 or 18 is rolled. (Therefore, there are
  no human characters with an attribute rating of 17 - a situation that
  must have the demographers in the game world puzzled. :) As usual,
  humans are the norm and use three dice for every attribute. The
  physical attributes consist of Strength, Prowess, Endurance, Beauty,
  and Speed, while the mental attributes are the I.Q., Endurance, and
  Affinity.
  
  Palladium is a derivatory game system that borrows many ideas from
  AD&D, and thus acquires the same benefits and criticisms. Thus, the
  scaling issue is again dealt with via a level system using an
  exponential point schedule. The non-humanoid creatures are almost
  completely lacking in attribute ratings, even compared to AD&D, and
  the game focus is heavily combat-oriented. While this is grand for a
  hack-and-slay style of play, it becomes difficult to judge
  human-creature interactions, or even guess at the psychological
  behavior of a fantasy beast.
  
  The ability to cast spells has been completely divorced from the
  attribute ratings, and is now only limited by the abstract level
  rating. However, there is also no correlation between I.Q. and spell
  learning. Whether this is realistic or not is left to the judgement of
  the reader, but it does make for more flexible design of magic-using
  characters. It was also a sensible design decision to use a Willpower
  attribute, rather than Wisdom.
  
  GURPS, 1985 - A skills-based system that uses a standard number of
  points to build characters, resulting in a non-random, relatively
  balanced process that allows for a wider variety of designs. This is a
  departure from many role-playing systems of the past which completely
  relied on random attribute generation, and skills grouped by a few
  archetypes. The result is a flexible game system that now has the
  broadest scope of published genres in the industry.
  
  The character generation process is not perfect, however, as the
  points balance is optimized for characters that are close to the human
  average. Exponential attribute scale is introduced by means of an
  increasing point cost to improve both attributes and skills. While
  this works well for low point level, skills-based campaigns, it
  becomes unbalanced as the base point total increases.
  
  For example, suppose a player decides to spend 64 points on skills and
  attributes. If the player spends 0 points on dexterity (DX) and 16
  points each on 4 average physical skills, the required 3d6 dice roll
  for success on each skill is 13 or less. However, if 45 points is
  spent on DX and 4 points each on the same 4 skills, the required skill
  roll becomes 15 or less, and you have an extra 3 points to spend! 
  Clearly the incentive is to spend more points on DX and IQ, producing
  high talent, less trained characters. (It is easy to argue that the
  result is realistic in terms of the talent capabilities of the
  character, but the problem is one of game balance. To use game slang,
  the system is encouraging munchkinism.)
  
  Similar complaints apply to non-human racial packages that apply an
  attribute modifier. The character can gain a hidden point bonus for
  selecting a non-human, especially if the bonus is large. Another
  problem arises because the same point schedule is applied to all four
  attributes. In mechanized game genres, Strength is less likely to be
  used than Dexterity or Intelligence, yet they cost the same number of
  points.
  
  At first glance, there are only four main attributes, with Strength,
  Dexterity, and Health for physical, and Intelligence for
  mental. However, additional adjustable attributes of Willpower,
  Charisma, Magical Attributes, and Magic Resistance are contained in
  the advantages and disadvantages sections. This is not necessarily a
  bad arrangement, as these attributes are less likely to be modified
  for a typical character, and have a lower impact on the game. The
  point schedule for these extra attributes is linear, unlike the base
  four. The extra Magic attributes allow low intelligence, magic-using
  characters to be built, although an IQ-based skills roll is still
  required for the standard GURPS magic system.
  
  Despite the minor inequities in the point-based approach, GURPS is
  still a big improvement over previous systems. Control of the
  character generation process is placed firmly in the hands of the
  player, and the result is better role-playing with more interesting
  and suitable personas.
  
  Central Casting: Heroes of Legend, 1988. Intended as a gaming aid,
  this detailed set of character history generation tables includes a
  simple set of rules for converting the resulting character into
  another game system. The result is telling in terms of what is
  required to create a reasonably portable character. Unfortunately, a
  drawback of this tool is that there is no method to work backwards
  from an existing character and build a past history. You are expected
  to be building the character from scratch.
  
  The physical attributes used in CC:HoL are Strength, Dexterity,
  Constitution, and Appearance, while the mental attributes are
  Intelligence and Charisma. There is also a Magical Aptitude and the
  character's Age when adventuring begins.
  
  Ars Magica, 1988. A medieval fantasy role-playing system with a focus
  on the magic-using party members, Ars Magica uses a skills-based
  character design system. The physical attributes are paired as
  Strength / Stamina and Dexterity / Quickness. Mental attributes are
  paired as Intelligence / Presence and Communication / Perception.
  
  The primary Attributes have a range from -9 to +9, with a base of
  zero. The values can be chosen by rolling dice, assigning points, or
  using one of the pre-generated characters. Random attributes are
  generated by using four 2d10-11 dice rolls. The results are then
  divided among the pairs of related Attributes.
  
  Due to the heavily magic-oriented nature of the game, every Magus is
  given what is effectively a Magical Ability attribute in each of the
  15 arts. The arts are divided into five techniques (what you do) and
  ten forms (what you affect) that provide the basis of every
  spell. When combined with the ability to cast ritual (cookbook) spells
  or spontaneous spells, this produces a very powerful and flexible
  magical system. The character is not restricted to a particular
  'style' of magic - rather an economic decision must be made by the
  player concerning where the magical abilities are focused.
  
  Creature scaling is handled (somewhat) by means of an exponential Size
  attribute. The Size attribute increases the amount damage larger
  creatures can withstand, but has no such effect on smaller
  animals. Animal intelligence is measured using a Cunning score, which
  measures clever behavior, yet prevents the use of skills using reason
  or language.
  
  Warhammer, 1989 - This English role-playing game was originally built
  around a fantasy game world that focused on the conflict between order
  and chaos. The attributes are designed for a medieval fantasy genre
  that is focused on short-ranged physical combat and a class-based
  social structure. Characters have a large number of attributes that
  intermix skills and characteristics in a peculiar fashion, with ranges
  a mixture of 1-10 and percentage. Fortunately, the game rules are
  simple enough that this peculiar mix does not detract from player
  understanding, and in practice the system does have a certain unique
  charm.
  
  For humans, the attributes of Initiative, Dexterity, Leadership,
  Intelligence, Cool, Willpower, and Fellowship all have a range of
  22-40, giving a slightly better differentiation than a 3d6
  roll. However, the attributes of Strength, Toughness, and Wounds lie
  in the range of 1-10, making this a linear distribution with a very
  poor point differentiation. Finally, Weapon and Ballistic attributes
  (skills?) are randomly generated as 2d10+20, and Movement is in the
  range of 3-5.
  
  No effort has been made to use non-linear attributes, and even the
  experience point scale is flat. However, the character is able to
  spend points to increase attribute values beyond the initial
  values. The large number of mental attributes is unusual for a
  medieval-era role-playing game, although some appear to be of only
  limited utility. Finally, as there is no direct connection between a
  skill level and the attribute scores, Wizards with low intelligence
  are only limited when it comes to learning a new spell, so dumb
  magic-users are possible, but unlikely.
  
  Shadowrun, 1989. This future Sci-Fantasy game system uses skills-based
  character design, with a dice-heavy event evaluation scheme. The
  physical attributes consist of Body, Quickness, Strength, while the
  mental attributes are Intelligence, Charisma, and Willpower. To handle
  the interaction of magic with technology, the additional attributes of
  Essence and Magic begin with a fixed rating of six. (Magic is no
  greater than Essence, but can be zero.)
  
  To build a character, a priority is assigned to five different
  categories of ability groupings. The priority assigned to the
  Attributes category determines how many total points can be assigned
  to the six core Attributes. (The total ranges from 15 points for
  priority E to 30 points for priority A.) The Attributes for humans
  range from one to six, while non-humans can have greater or lesser
  maximum values for different attributes. Dice rolls are compared
  individually to these ratings, hence the small range.
  
  The small values for the Attributes does not provide good
  differentiation between characters, but the game compensates by
  including a wide variety of special add-ons, such as skills, magic,
  cyberwear, and gear. The scaling issue is handled by means of a
  geometric growth in the amount of karma (experience) needed to improve
  Skills and Attributes. (The use of karma in this system is actually a
  nice economic concept, allowing players to spend from a reserve to
  influence key events during a game.)
  
  Creatures use the same set of Attributes as characters, with a fixed
  value for each attribute. However, only Strength and Body are
  generally given Attributes beyond eight. While this limits the impact
  of scaling, it does tend to make all creatures look similar. As this
  is an urban-heavy genre, this limitation is not a big issue.
  
  Shadowrun uses a cyberwear-negates-magic approach to magical
  ability. As more cyberwear mods are connected to the nervous system,
  the character loses essence, and hence magic. This reasonable game
  balancing mechanism creates a strong distinction between magic users
  and the cyber-enhanced mundanes. Magic skill from the Hermetic
  tradition is weakly tied to Willpower, but no other Attribute,
  allowing flexibility in character design.
  
  Hero, 1990. Benefiting from the lessons of past role-playing games,
  Hero has one of the most balanced and flexible character building
  systems in the industry. In many respects, the point-based
  construction method is similar to GURPS. However, the Attributes are
  now weighted according to their game value to the player. Thus
  Comeliness, which normally has a low impact in a game, only costs a
  half point per level of increase. In contrast, Dexterity costs three
  points per level of increase, as this is a much more useful
  attribute. (To see why, you will need to review the remainder of the
  rules system.)
  
  The base physical attributes are Strength, Dexterity, Constitution,
  Body, and Comeliness, while the mental attributes are Intelligence,
  Ego, and Presence. Normal human attributes start with a base score of
  ten each, with a maximum limit of twenty for mundane genres. Of the
  normal attributes, the only one that might be at issue is the Body
  attribute, since it would appear reasonable to derive Body from the
  Constitution.
  
  Several derived attributes are also used, and they can be modified by
  spending points. The large number of such attributes, while required
  due to the Hero combat model, are probably confusingly excessive and
  result in overtuning of the creatures and characters. It would have
  been cleaner, and less prone to error, if the primary attributes were
  used directly - treating most of the derived attributes as advantages
  instead.
  
  In a break from past systems, the physical attributes of Strength and
  Body are now based on an exponential scale. Every five points of
  Strength results in a doubling of true physical strength. This allows
  strengths ranging from a small mouse to a powerful ship to be modelled
  on a scale of only a hundred points, and allows Hero to readily model
  super-heroic characters without grossly distorting game balance. It
  now becomes clear why Body is required - as a counter-weight to the
  Strength attribute.
  
  As all the attributes use a linear point cost scale, there is no
  particular benefit to selecting extreme values. Rather, the player is
  forced to make economic trade-offs between the attributes in order to
  match the character concept. The effect of the attributes are rather
  watered down when applied to skills, however, resulting in somewhat
  bland human normals.
  
  The Hero powers system allows the development of virtually any type of
  magic-using character. The lack of Magical Aptitude or Magical
  Resistance attributes are missed in the Fantasy genre,
  however. Instead, the supplied colleges of magic use a rather
  heavy-handed incentive to encourage specialization. Attempting to
  build a component-based magic system, such as Ars Magica, is all but
  impossible in Hero, unless an absurd number of points are allowed to
  the players. {Note that I have since seen the error of this belief, as
  a VPP can easily be used to build such a system - 07/24/98.]
  
  (Note that HERO is in the process of being reinvented in the form of a
  merged role-playing system known as Fuzion. The rules for this new
  system are available online at
  http://www.sabram.com/rtalsoriangames/site/fuzion/index.html. Many of
  the attributes remain the same, but now even more derived attributes
  have been added. It is not difficult to imagine what effect this
  attribute inflation will have on new players. However, take a look at
  the rules and judge for yourself. )
  
  Dangerous Journeys, 1992. Following a highly promoted introduction,
  this role-playing system fizzled and was essentially snuffed following
  a buy-out by TSR. (The chief complaints by players seem to be the
  difficult writing style used in the manuals, and some major rules
  gaffs. The manuals were badly in need of a good editor, some major
  reorganization, and more play testing prior to release. The peculiar
  terminology and acronyms didn't help any.)
  
  In many ways the game system is a throw-back to an earlier style of
  class-based character building, with a nod towards a skills-based
  systems. Characters are assigned to a social class, then they have a
  limited choice of vocations within that class. While the system is
  labelled as multi-genre, it appears decidedly oriented towards an era
  when a career was decided by birthright. (I.e. ancient and/or medieval
  periods.)
  
  The attributes are categorized into mental, physical, and spiritual
  Traits. The Traits are sub-divided into two Categories each: Mnemonic
  and Reasoning for mental, Muscular and Neural for physical, and
  Metaphysical and Psychic for spiritual. Finally, each of the
  categories are further divided into the Attributes of capacity, power,
  and speed. Needless to say, this results in a lot of attributes.
  
  For the player's character, the eighteen character attributes are in
  the range from 10 to 20. To generate this range, either a roll of
  2d6+8 is used, or the numbers 50, 45, 45, 40, 40, and 35 are assigned
  to the attribute Categories, then dividing the totals among the
  Attributes. (By comparison, a typical human has an attribute rating of
  10, plus or minus 1d6.)
  
  Attributes can be improved with the expenditure of Accomplishment
  Points. However, the point scale is entirely linear, as, it would
  appear, are the attribute effects. Magic skill levels are entirely
  attribute-based, although the skill level can then be improved by
  spending points.
  
  Role Master, 1995. This mix of a class and skills-based system uses
  percentage dice to evaluate all actions. Characters are required to
  have a fixed profession, but have some flexibility in deciding which
  skills to develop. However, skills outside the characters area of
  expertise require more experience points to develop.
  
  The character generation system allocates a random number of points
  (600+10d10) that are used to build the stats. All stats have a value
  between 1 and 100. However, depending on the profession selected for
  your character, certain stats are designed prime, meaning they must
  have a minimum value of 90. All the remaining stats for a player's
  character have a minimum value of 20. For stats below ninety, the
  point cost is linear. Beyond that point, however, the costs begin to
  escalate from a cost of 91 for a stat of 91, to a cost of 190 for a
  stat of 100.
  
  For physical attributes, the game uses Agility, Constitution,
  Quickness, and Strength. The mental attributes are Memory, Reasoning,
  Self Discipline, Empathy, and Intuition. Presence is used as both a
  mental and physical stat. Of these stats, Agility, Constitution,
  Memory, Reasoning, and Self Discipline are considered to be
  development stats, because they aid in character improvement. Each
  time a character climbs a level, they receive development points equal
  to the sum of their development stats. These can then be expended to
  improve skills, using a class-based weighting scheme for each skill
  category.
  
  Each stat is given a temporary stat rating and a potential stat
  rating. As a character increases in level, a random check is made to
  determine if each temporary stat has changed. Increases in the
  temporary stat are limited only by the potential stat rating.
  
  Creature scaling is implemented by means of an escalating experience
  point schedule. Combat damage is handled by the unusual expedient of
  using a separate table for each weapon category and armor type, but in
  general the damage level increases in a non-linear fashion. Finally,
  each stat has a bonus that increases more rapidly as the score
  approaches 100 (and decreases equally quickly for stats close to 1.)
  
  If you like class-based systems with a variety of character types,
  lots and lots of tables for evaluating every possible action, and a
  convoluted skill evaluation and character improvement system, then
  RoleMaster is for you. There are players who swear by RM...I guess it
  takes all types.
  
Common Attributes

Now that the survey of the game systems is complete, it is time to take
a look at what they all have in common. Here is a list of the attributes
used in many role-playing systems, and an explanation their meaning:

  Strength - A measure of the characters ability to exert physical
  force. The attribute is also referred to as Physical Strength. The
  Strength attribute factors into the ability to lift and carry heavy
  loads; the amount of damage inflicted through a blow; and restricts
  the types of manual tools that can be operated easily.

  Dexterity - The relative ability to react physically to a brief
  event. Dexterity is also called Agility, Reflexes, or Physical
  Prowess. It differs from pure exertion of strength, and requires tight
  coordination between the central nervous system and the
  musculature. This attribute is used to evaluate most competitive
  physical skills, such as striking a target with a missile, or dodging
  a blow.
  
  Finesse - The degree of fine motor control required to manipulate
  delicate objects. Finesse is also known as Manual Dexterity or
  Technique. It is related to Dexterity, but more focused on hand-eye
  coordination. Finesse is used to disable or repair small mechanisms,
  assemble delicate devices, and remove items from awkward locations.
  
  Health - The gross physical well being of the creature, health
  measures the ability to withstand disease, toxins, and other
  unpleasantries. It also determines how rapidly recovery from damage
  occurs. Health is also known as Constitution or Hardiness. Health can
  be used to determine how much time is required to recover from long
  term exhaustion, such as might be experienced following a marathon.
  
  Fatigue - The short term physical energy that the character can expend
  before becoming exhausted. It is also called Energy. This attribute
  places a more realistic cap on the characters activities during a
  battle, and is also used to limit magical powers.
  
  Endurance - A rating of how much cumulative damage a creature can
  withstand before dying. Endurance is also referred to as Hit Points or
  Body. In systems that do not include defensive skills, Hit Points are
  also used to measure the amount of combat experience. This mixture of
  unrelated physiological and combat capabilities within a single
  parameter can have a distorting effect, resulting in an unrealistic
  model. However, it does have the side benefits of making combat less
  bloody and more protracted at higher levels, as the characters are
  rarely eliminated by a single blow.
  
  Appearance - The physical attractiveness of the character,
  particularly with regards to the opposite sex. This attribute has also
  been called Comeliness and Beauty. The effect on game play is less
  useful than most physical attributes, being required primarily during
  social situations. However, physical beauty has been known to enjoy
  subtle effects on the human psyche, inspiring loyalty and trust beyond
  the norm.
  
  Intelligence - The mental ability to remember facts and employ
  reasoning to analyze a problem. Known also as I.Q., Memory, and
  Reasoning. Intelligence is also a crude rating of the ability to use
  mathematics, solve puzzles, learn a new language, create music, etc.
  
  Quickness - The speed of reaction to a rapidly changing
  situation. Quickness is also known as Reaction or Initiative. It
  determines who reacts first during a crisis, allowing a quick witted
  character to get the jump on a foe. Quickness is closely related to
  the Dexterity attribute.
  
  Size - The gross physical proportions of a creature. Also known as
  Height or Growth. This attribute is often used to handle scaling
  issues, such as visibility, melee reach, minimum opening required to
  enter a room, etc.
  
  Cool - This measures the ability of the character to remain calm under
  conditions of duress, such as during combat or when facing a truly
  terrifying sight. It is also called Morale, and is a measure of a
  creatures steady reaction to a panic situation. In AD&D, this
  Attribute is only used for creatures, and the morale aspects of the
  characters are handled directly by the players.
  
  Wisdom - An Attribute that measures a characters worldly knowledge and
  common sense. Also known as empathy. It is used, probably incorrectly,
  as a magical attribute for priestly magic. Most modern systems use
  willpower or piety, and leave knowledge evaluation to a skills system,
  various advantages, and/or role-playing.
  
  Cunning - A primal form of intelligence available to many animals,
  cunning measures a creatures ability to quickly formulate good
  reactions to stressful conditions. For humans, this measures wits, and
  is closely related (if not identical) to quickness. Cunning is useful
  for evaluating a changing tactical situation, coming up with a witty
  rejoinder during a discussion, taking advantage of a lucky break, and
  so on.
  
  Willpower - The amount of self-control a character has over his own
  mind and body. This attribute is also called Mental Endurance, Self
  Discipline, and Ego. It is often used as a measure of a characters
  control over arcane forces, the ability to resist the imposition of
  another's will, and the degree of vulnerability to fearful thoughts
  and experiences. Willpower is closely related to cool.
  
  Leadership - The ability to influence the behavior of others using a
  commanding presence, persuasive dialogue, and appealing behavior. This
  attribute has also called Charisma, Mental Affinity, Power, or
  Presence. It does not imply an ability to lead sensibly, but does
  enhance the loyalty and morale of friends and allies under
  discouraging conditions. Some systems use a separate set of leadership
  skills.
  
  Fellowship - The ease with which a character associates with others in
  a social environment. Many systems use a skill to handle this ability,
  although some people do seem to have an innate ability to get along
  well with others.
  
  Movement - This derived attribute is used to determine how far a
  creature can move during an interval of time. Movement is also called
  Speed. Typically the movement rate is a fixed value for each race,
  with a modifier based on the Dexterity Attribute. Separate factors are
  also used for measuring different means of movement, such a swimming,
  flying, tunneling, etc.
  
Each of the following special attributes are generally used only in a
limited number of game genre:

  Magical Aptitude - The general ability of a character to summon arcane
  forces for executing his will. It is also called Magical Ability. This
  attribute is usually employed when a game system creates a unique
  mechanism for employing magic, rather than relying on a character's
  mental attributes.
  
  Psionic Ability - The measure of a characters ability to employ
  psychic forces using mental techniques. Willpower is frequently used
  to determine how much control the character has over the resulting
  abilities. This ability is usually used in a Sci-Fi setting, as a type
  of rationalized magical ability.
  
  Piety - This attribute expresses the characters degree of belief and
  worship of a supernatural entity (or entities.) Piety is used to
  adjudicate the amount of influence the character has on the
  intervention of the entity in the real world. It is also called the
  Metaphysical attribute, and is usually related to Wisdom.
  
  Sanity - Used primarily in horror genre, this attribute measures your
  psychological fitness as compared to the human norm. It is also known
  as Humanity. Many role-playing systems have special rules for handling
  the different forms of insanity.
  
  Luck - The typical amount of good fortune that a character
  experiences. Luck is also known as Karma or Intuition, and can include
  bad luck. This attribute is appropriate for a genre where mystical
  forces influence character actions. Limited use of a luck attribute
  can also be used with a cinematic style, where the heroes sometimes
  receive fortunate breaks that move the story forward. (Systems that
  use this technique include Warhammer and Shadowrun.)
  
It is telling that in almost all role-playing systems the characters
weight and age have little bearing on the resulting attributes except in
extreme cases. Multi-genre systems do treat these factors as
disadvantages when they reach abnormal values - resulting in penalties
to Attributes and Abilities. Otherwise they are basically ignored under
most circumstances.

New System

Okay, here is my attempt to put together a decent attribute system using
the preceding analysis. I start by establishing the usual separation
between mental and physical attributes, but I want to tie the two
together by correlating mental thoughts with physical actions. This will
allow me to make some interesting tie-ins between physical and mental
combat, as well as making the attributes more intuitive to the player.

As I want to include a commonly used set of attributes to make the
system easy to pick up for an experienced player, I will use Strength,
Dexterity, Health, Intelligence, Willpower, and Leadership. However, I
also want a mental equivalent to Dexterity, so I will use a Wits
attribute to measure the ability to think quickly. The Leadership rating
also needs a physical equivalent, so I will add in Quality. (A social
attribute that describes physical desirability, symmetry, proper
physical function, and general lack of congenital defects.) After a
slight renaming, the attributes are arranged in the neat little chart
shown below:

  Type      Physical         Mental
  Power     Strength (ST)    Intellect (IN)
  Speed     Dexterity (DX)   Wit (WT)
  Inertia   Hardiness (HD)   Willpower (WP)
  Social    Quality (QU)     Leadership (LD)

The next decision is to use a logarithmic scale for all the
attributes. This allows the game to handle wide extremes of creatures
and abilities, and thus a large number of different genre. It will also
make scale factors, such as area effects or force multipliers, easier to
include when building abilities - we can just add or subtract a
modifier, rather than multiplying by a fraction.

Choosing a reasonable, but purely arbitrary scale, I decide that every
ten points of attributes will result in a ten-fold increase of
capability. (Hence, a character with a strength of 20 is ten times as
strong as strength 10.) This will cover most extremes of human
capability within a twenty point range.

However, this non-linear scale could have some peculiar effects on event
evaluation. To balance out the exponential scale, some form of skewed
dice distribution will need to be used, such as adding the lowest three
dice values out of a total of four rolls. To keep it simple, I'll assume
that only six-sided dice will be used, and that a normal human attribute
range is 3 to 18. (The lowest two out of three ten-sided dice could also
have been used, with a larger variance in the results.)

To see why the dice distribution needs to be skewed toward a lower
result, see the table below. The first column of the table lists the
ability scores on our 3 to 18 range. The second column shows the real
world power rating that corresponds to the ability score. (I.e. a rating
that you could theoretically measure if you gave the character an
attribute test, such as weight-lifting for Strength, or an IQ test for
Intelligence, etc.) In the third through the fifth columns, the
percentage odds for rolling a matching dice total is listed for three
different methods.

   Ability Power  Total of 3d6 Lowest 2 and High of 4d6 Lowest 3 of 4d6 
           Rating    % Odds             % Odds              % Odds      
                                                                        
      3     2.0       0.5                0.1                  1.6       
                                                                        
      4     2.5       1.4                0.7                  4.2       
                                                                        
      5     3.2       2.8                2.0                  7.3       
                                                                        
      6     4.0       4.6                4.5                 10.1       
                                                                        
      7     5.0       6.9                8.3                 12.4       
                                                                        
      8     6.3       9.7                13.8                13.3       
                                                                        
      9     7.9       11.6               15.9                12.9       
                                                                        
     10     10.0      12.5               15.7                11.4       
                                                                        
     11     12.6      12.5               13.4                 9.4       
                                                                        
     12     15.8      11.6               10.4                 7.0       
                                                                        
     13     20.0      9.7                6.9                  4.8       
                                                                        
     14     25.1      6.9                4.1                  2.9       
                                                                        
     15     31.6      4.6                2.2                  1.6       
                                                                        
     16     39.8      2.8                1.0                  0.8       
                                                                        
     17     50.1      1.4                0.3                  0.3       
                                                                        
     18     63.0      0.5                0.1                  0.1       

The weighted average power rating is computed by multiplying each of the
individual power ratings by the corresponding odds, then totalling the
results. The average power rating for a normal 3d6 roll is 14.1, roughly
equivalent to an attribute rating of 12 - much higher than the
population median of 10.5. When you use the lowest three out of four
rolls, however, the weighted average drops to 9.4, a closer match. The
decreased odds of rolling a higher score is now compensating for the
rapidly increasing power ratings. Adding the lowest two and the highest
roll produces an average power rating of 11.5, which is just as good but
skewed to the high side.

The lowest 3 of 4 distribution comes at a price, however, as the median
characteristic is now 8.5. This means that for any particular attribute,
more than half the population is below average. Using the low 2 and
highest roll has a median of 9.5, much closer to the population
median. Of the two skewed distributions, the later method appears to
produce the best results.

We've now got a method for generating random attributes for a member of
population - roll four six-sided dice for each attribute and total the
lowest two and the highest rolls. We can justify the slightly lower
median score by saying that most people fail to live up to their true
potential in all attributes, or we could just accept it as the price of
game balance.

To provide better differentiation between population members, I'll also
generate a potential attribute score - giving the maximum attribute
score the character could achieve if he or she really applied him or her
self. This will help to balance out the population median issue
mentioned above.

To compute the potential score, use the same dice roll used to generate
the attribute, and substitute the second highest dice score for the
second lowest dice score. (E.g. on a roll of 1, 3, 4, 6, the attribute
is 1+3+6=10, and the potential becomes 1+4+6=11.) This method will
guarantee that that potential is at least equal to the attribute, and
will usually allow a one or two point growth potential.

Genres with specialized attribute requirements, such as magical aptitude
or psionic ability, are handled as advantages with their own set of
special rules. The GM can have the option of treating them as modifiers
to an existing attribute, or using them as stand-alone characteristics
with a default base.

Finally, if a point-based system is to be used for character generation,
we'll need to be consistent during the design process and use
exponential abilities and skills as well. Built in limits will still
need to be applied to prevent point abuse by power gamers.

That does it - a set of attributes that matches many of the criteria I
had listed earlier. The effect of the remaining attributes common to
other systems can be replicated by using derived attributes. (Likely
candidates appear to be: Size, Fatigue, Endurance, Finesse, and
Movement. The Cool, Wisdom, Fellowship, Magical Aptitude, Sanity,
Psionic Ability, Piety, and Luck attributes will be handled as
advantages, if at all. But that awaits another step in the design
process.)  

References

    - A Description-Based RPG System, Charles Ryan, 1995.
    - Advanced Dungeons & Dragons, Second Edition, TSR Inc., 1989.
    - Central Casting: Heroes of Legend, Paul Jaquays, 1988.
    - Dangerous Journeys: Mythus, Gary Gygax, 1992.
    - DragonQuest, Second Edition, Simulations Publications, Inc., 1981.
    - GURPS Basic Set, Third Edition, Steve Jackson Games, 1989.
    - RoleMaster Standard Rules, Iron Crown Enterprises, 1995.
    - RuneQuest, Deluxe Edition, The Avalon Hill Game Company, 1993.
    - Shadowrun, Second Edition, FASA Corp., 1992.
    - The Palladium Role-Playing Game, Revised Edition, Kevin Siembieda, 1993.
    - Warhammer Fantasy RolePlay, Games Workshop, 1986.
--<cut>--

--
J C Lawrence                
---------(*)                Satan, oscillate my metallic sonatas. 
claw at kanga.nu               He lived as a devil, eh?		  
http://www.kanga.nu/~claw/  Evil is a name of a foeman, as I live.

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