====== GURPS Core Resources: Skill Notes ======

A 'skill' is a particular kind of knowledge; for instance, judo, physics, auto mechanics, or a death spell. Every skill is separate, though some skills help you to learn others. Just as in real life, you start your career with some skills and can learn more if you spend time training.

A number called 'skill level' measures your ability with each of your skills: the higher the number, the greater your skill. For instance, 'Shortsword-17' means a skill level of 17 with the shortsword. When you try to do something, you (or the GM) roll 3d against the appropriate skill, modified for that particular situation. If the number you roll is less than or equal to your modified score for that skill, you succeed! But a roll of 17 or 18 is an automatic failure.

Each skill is qualified in several ways to indicate what basic attribute represents talent with that skill, how easy the skill is to learn, any special restrictions on who can learn the skill, and whether the skill is broad or narrow in focus.

===== Controlling Attribute ===== 

Each skill is based on one of the four basic attributes or, more barely, on Perception or Will. Your skill level is calculated directly from this 'controlling attribute': the higher your attribute score, the more effective you are with every skill based on it! If your character concept calls for many skills based on a given attribute, you should consider starting with a high level in that attribute, as this will be most cost-effective in the long run.

ST-based skills depend wholly on brawn, and are very rare. ST determines the power you can bring to bear with DX-based skills far more often than it affects skill levels directly.

DX-based skills rely on coordination, reflexes, and steady hands. This is representative of athletic and combat skills, and most vehicle-operation skills.

IQ-based skills require knowledge, creativity, and reasoning ability. This includes all artistic, scientific, and social skills, as well as magic spells.

HT-based skills are governed by physical fitness. This includes any activity influenced by hygiene, posture, or lung capacity.

Perception-based skills involve spotting subtle differences. This is typical of skills used to detect clues and hidden objects.

Will-based skills hinge on mental focus and clarity of thought. Most allow one to resist mental attacks, bring about an altered mental state, or focus 'inner strength.'

===== Choosing Your Beginning Skills ===== 

Like attributes and advantages, skills cost points. You should spend at least a few of your starting character points on skills. It would be extraordinarily unusual for anyone - even a young child - to have no skills at all!

Your starting skills must suit your background. The greater your Wealth and Status, the more leeway the GM will allow you in skill choice - the rich and powerful can arrange to learn the most surprising things. You cannot start with inappropriate skills, however. The GM is free to forbid any skill that simply would not be available to someone of your background. For instance, a stone-age hunter could not be a jet pilot, a Victorian gentleman would need an excellent explanation (and an Unusual Background) to start out as a skilled sorcerer, and a futuristic adventurer would have difficulty finding training in 'archaic' weapon skills... though a military background would help.

===== Difficulty Level ===== 

Some fields demand more study and practice than others. GURPS uses four 'difficulty levels' to rate the effort required to learn and improve a skill. The more difficult the skill, the more points you must spend to buy it at a given skill level.

Easy skills are things that anyone could do reasonably well after a short learning period - whether because they are second nature to most people or because there isn't a whole lot to learn.

Average skills include most combat skills, mundane job skills, and the practical social and survival skills that ordinary people use daily. This is the most common difficulty level.

Hard skills require intensive formal study. This is typical of most 'academic' skills, complex athletic and combat skills that require years of training, and all but the most powerful of magic spells.

Very Hard skills have prodigious scope, or are alien, counterintuitive, or deliberately shrouded in secrecy. The most fundamental of sciences, and many potent magic spells and secret martial-arts techniques, are Very Hard.

===== Technological Skills ===== 

Certain skills are different at each tech level. These 'technological skills' are designated by '/TL.' This means that when you learn the skill, you must learn it at a specific tech level (TL). Always note the TL when you write down such a skill; e.g., 'Surgery/TL4' for the TL4 version of Surgery skill. Surgery/TL4 (cut his arm off with an axe) is nothing like Surgery/TL9 (graft on a replacement arm from his clone)!

You learn technological skills at your personal TL. You may also choose skills from a lower TL. You can only learn skills from a higher TL in play, and only if you have a teacher and the skill is not based on IQ. To learn IQ-based technological skills from a higher TL, you must first raise your personal TL.

Technological skills rely on language, tool use, or both. This means that only sapient characters - those with IQ 6 or higher - may learn them. Exception: Robots and the like can have IQ 5 or less and perform such skills by running programs... but of course programming isn't learning.

===== Tech Level Modifiers ===== 

Technological skills work best with the specific artifacts and techniques of their own TL. WHen you work with equipment or concepts of a TL different from that of your skill, you suffer a penalty to your skill roll.

==== IQ-Based Technological Skills ====

IQ-based technological skills represent a studied technical understanding of the specific methods and tools common at a particular TL. There is a penalty to your skill roll when you use these skills with the equipment of a higher TL (which relies on scientific and engineering principles unknown to you) or a lower TL (which depends on principles that were, at best, a 'historical footnote' during your training.)

^ Equipment TL ^ Skill Penalty ^
| Skill's TL + 4 or more | Impossible! |
| Skill's TL + 3 | -15 |
| Skill's TL + 2 | -10 |
| Skill's TL + 1 | -5 |
| Skill's TL | 0 |
| Skill's TL - 1 | -1 |
| Skill's TL - 2 | -3 |
| Skill's TL - 3 | -5 |
| Skill's TL - 4 | -7 |
| Per extra -1 to TL | -2 |

==== Other Technological Skills ====

Technological skills based on attributes other htan IQ let you use technology; they do not assume any real understanding of the science or engineering behind the tools. For instance, a TL5 gunslinger accustomed to firing a Colt Peacemaker might find a TL7 Colt Python a bit strange, but he would have little difficulty shooting it.

For skills like this, apply a flat penalty of -1 per TL of difference between the skill and the equipment. For instance, a TL5 gunman would be at -2 to shoot a TL7 revolver. It is irrelevant whether the equipment is more or less advanced - a TL7 policeman would be at -2 to fire a TL5 revolver, too.

===== Grouped Skills =====

A set of distantly related skills that use identical rules may appear under a single heading to avoid repetition. If a skill description does not say that you must specialize, and indicates that it represents a collection of skills, then the sub-entries represent stand-alone skills - not specialties. Use only the name of the relevant sub-entry when you refer to such skills.

Example: Hand-to-hand weapon skills are grouped under Melee Weapon, but if you learn to use a shortsword, write 'Shortsword', not 'Melee Weapon (Shortsword).'

===== Prerequisites =====

Some skills have other skills as prerequisites. This is the case when an advanced skill is based on, and in some ways an outgrowth of, a basic one. To study the advanced skill, you must have at least one point in the prerequisite skill.

Certain skills also require that you know a prerequisite skill at a minimum skill level. Where this is the case, you must spend the points required to learn the prerequisite skill at the specified level before you can learn the advanced skill.

A few skills have advantages as prerequisites. In order to learn such a skill, you must possess the required advantage. If you do not have the advantage, and cannot acquire it in play, you can never learn that skill.

===== Specialties =====

An entry on the skill list may represent an entire category of closely related skills that share a single skill name. Examples include Armoury and Survival. Skills like this are marked with a # in the skill list. The skills within such a category are called 'specialties.' When you buy a general skill of this kind, you must specify which specialty you are learning. On your character sheet, note the name of the specialty in parentheses after the general skill name; e.g., 'Armoury (Small Arms)' or 'Survival (Arctic)'.

You may learn skills like this any number of times, with a different specialty each time, because each specialty is a different skill. There is usually a favorable 'default' between specialties, which may let you purchase additional specialties more cheaply.

===== Optional Specialties =====

Many IQ-based skills - notably 'academic' skills such as Literature and Physics - have countless subfields but do not require you to select a specialty. As written, if you learn a skill like this, you are a generalist, knowledgeable about every aspect of the skill. However, you may opt to specialize in a single, narrow area. You may only do this with an Average or harder IQ-based skill, and only if the GM agrees that the chosen subfield is logical given the skill and your TL.

When you choose an optional specialty, write down the skill and its specialty just as if you were selecting a required specialty. You learn the specialized skill as if it were one level easier. Unless otherwise noted, prerequisites are unchanged. The general skill defaults to the specialized one at -2; roll against this whenever you must answer questions outside your field. Any skill that defaults to the general skill also defaults to all of its optional specialties, but at an additional -2.

Example: Chemistry is IQ/Hard and does not require a specialty. You could learn the optional specialty Chemistry (Analytical) as if it were one level easier, or IQ/Average. Your general Chemistry skill would default to Chemistry (Analytical) - 2. Metallurgy, which normally defaults to Chemistry - 5, would default to Chemistry (Analytical) - 7.

===== Familiarity =====

Any skill used to operate equipment - e.g., Beam Weapons/TL11 (Pistol) or Driving/TL 7 (Automobile) - takes a penalty when you are faced with an unfamiliar type of item. For instance, if you were trained on a laser pistol, a blaster pistol would be 'unfamiliar'. Assume that an unfamiliar piece of equipment gives -2 to skill except where an individual skill description specifies otherwise.

In general, if you have the skill to use a piece of equipment, you are considered familiar with a new make or model after you have had eight hours of practice with it. Some skills require more or less practice than this, so be sure to read the skill description.

There is no limit to the number of types of gun, car, plane, etc, you can become familiar with. Each of these items is called a 'familiarity'. If you have at least six familiarities for a given skill, the GM may roll against your skill when you pick up a new piece of equipment. On a success, you are already familiar with something similar and may use the new device at no penalty. The GM may also rule that a new item is so similar to a known one that it is familiar - for instance, two similar models of Colt revolver should be considered identical.

Equipment from another tech level will usually be unfamiliar. This gives both TL and familiarity modifiers. Practice can eliminate unfamiliarity penalties, but to shed TL penalties, you must relearn the operation skill at the equipment's TL. Exception: Improved or obsolete versions of items with which you are already familiar do not give unfamiliarity penalties.

===== Familiarity for Beginning Characters =====

Starting characters may specify two familiarities per point spent on a skill. For instance, if you have four points in Guns (Pistol), you can be familiar with up to eight handguns.

Both specialization and familiarity come into play with many skills, but they are not the same thing. Driving (Automobile) is a specialty of Driving; it is a separate skill from Driving (Locomotive), and to know both, you must pay points for both. 'Volkswagen Bug' is a familiarity of Driving (Automobile); you can select it for free as one of your starting familiarities.

===== Skill Notation =====

When you write down a skill with a single specialty, either required or optional, do so in the form 'Skill Name (Specialty)'; e.g., Artist (Painting). If such a skill has multiple qualifiers, follow these guidelines:

-- Technological skills: Place the tech level after the skill name and before the specialty; e.g., Engineer/TL8 (Civil).
-- Skills with both required and optional specialties: If a skill that requires you to specialize also allows an optional specialty, write the required specialty before the optional specialty and separate the two with a comma; e.g., Artist (Painting, Oil).
-- Skills that require two specialties: In the rare case where a skill requires you to select two specialties, separate them with a slash; e.g., Geography/TL7 (Physical/Earth-like).

===== Buying Skills =====

In order to learn or improve a skill, you must spend character points. When you spend points on a skill, you are getting training to bring that skill up to a useful level. Skills are easy to learn at first - a little training goes a long way! But added improvement costs more.

The point cost of a skill depends on two things: its difficulty and the final skill level you wish to attain. Use the Skill Cost Table to calculate a skill's point cost.

The first column shows the skill level you are trying to attain, relative to the skill's controlling attribute - DX for DX-based skills, IQ for IQ-based skills, and so forth. For instance, if your DX were 12, a level of 'Attribute - 1' would be DX - 1, or 11; 'Attribute + 0' would be DX, or 12; and 'Attribute + 1' would be DX + 1, or 13.

The next four columns show the character point costs to learn skills of different difficulties - Easy, Average, Hard, and Very Hard - at the desired skill level. Harder skills cost more points to learn!

Example: A warrior with DX 14 wishes to learn Shortsword (DX/Average) at level 17. Since skill 17 is equal to his DX+3, he goes to the 'Attribute + 3' row. Then he reads along the row to the 'Average' column to find the point cost: 12 points.

There is no limit (except lifespan) to the amount of improvement possible with any skill. However, the useful maximum of most skills is between 20 and 30. Problems to challenge a greater skill are rare!

^ Your Final Skill Level ^ Easy Difficulty ^ Average Difficulty ^ Hard Difficulty ^ Very Hard Difficulty ^
| Attribute - 3 | -- | -- | -- | 1 |
| Attribute - 2 | -- | -- | 1 | 2 |
| Attribute - 1 | -- | 1 | 2 | 4 |
| Attribute + 0 | 1 | 2 | 4 | 8 |
| Attribute + 1 | 2 | 4 | 8 | 12 |
| Attribute + 2 | 4 | 8 | 12 | 16 |
| Attribute + 3 | 8 | 12 | 16 | 20 |
| Attribute + 4 | 12 | 16 | 20 | 24 |
| Attribute + 5 | 16 | 20 | 24 | 28 |
| Extra + 1 | +4 | +4 | +4 | +4 |

===== Improving Your Skills =====

There are two direct ways to increase your skills in play: spend the bonus points you earn for successful adventuring on new or better skills, or dedicate game time to study, which gives you points you can use to add or improve the skills you studied. In either case, the cost to improve a skill is the difference between the cost of the desired skill level and the cost of your current skill level.

===== Free Increases in Skills =====

There is one way to increase many skills at once: pay the points to improve an attribute. If you do this, all your skills based on that attribute go up by the same amount, at no extra cost. For instance, if you raise DX by one level, all of your DX-based skills also go up by one level. Further improvements are based on the new DX value.

You can also base skills on 'defaults' from other skills; see Defaulting to Other Skills. Any skill bought up from such a default is likely to enjoy a free increase when you raise the skill to which it defaults.

===== Meaning of Skill Levels =====

So you have Literature-9, Savoir-Faire-22, and Shortsword-13. What does that mean? What is good, bad, and average? That's very important when you create a character. It's also important if you're converting characters from another system into GURPS, or vice versa. There are two equally valid - but different - ways to make skill-level comparisons.

===== Probability of Success =====

The easiest way to get a feel for your skill levels is to look at your odds of success. To use a skill, you must roll 3d against your skill level. This is called a 'success roll'. For instance, if your skill is 13, you must roll 13 or less on 3d to succeed. The table below shows the probability of success at each skill level - that is, your chance of rolling less than or equal to a given number on 3d. Note that skill levels can be over 18, but a roll of 17 or 18 is automatically a failure. Nobody succeeds 100% of the time!

^ Skill Level ^ Probability of Success ^ Skill Level ^ Probability of Success ^
| 3 | 0.5% | 10 | 50.0% |
| 4 | 1.9% | 11 | 62.5% |
| 5 | 4.6% | 12 | 74.1% |
| 6 | 9.3% | 13 | 83.8% |
| 7 | 16.2% | 14 | 90.7% |
| 8 | 25.9% | 15 | 95.4% |
| 9 | 37.5% | 16+ | 98.1% |

===== Base Skill vs. Effective Skill =====

Your unmodified skill level is called your base skill. It measures your odds of success at an 'average' task under adventuring conditions - in other words, in a stressful situation where the consequences of failure are significant. Some examples:

-- Battles and chase scenes
-- Races against the clock
-- Situations where your health, freedom, finances, or equipment is at risk

The GM may modify your skill level to reflect the difficulty of a task. Your final skill level, after applying all modifiers for the task at hand, is your effective skill for that task.

In non-adventuring situations when you have lots of time to prepare and face minimal risk, the GM may give you +4 or more to skill. (The GM might even declare such actions successful instead of wasting time on a skill roll.) Ordinary people almost always receive this bonus at mundane tasks, even if they are working from default skill!

Example: An airline pilot has Piloting-12 - normally a 74% chance of success. For day-to-day flying, however, he rolls at +4. This makes his effective skill 16, for a 98% chance of success.

On the other hand, especially tough adventuring situations can result in penalties. Culture, Language, Tech Level Modifiers, Familiarity, Equipment Modifiers, and Task Difficulty are some examples of common modifiers. Be sure to take these factors into account when buying your skills.

===== Relative Skill Level =====

Skill level reflects a combination of talent and training. For instance, a DX 17 warrior has a lot of raw talent. He could quickly learn Shortsword-17, as this is only DX level for him. A DX 10 fighter would need considerably more practice to become that skilled, as Shortsword-17 is DX+7 level for him.

Such details are often unimportant; two warriors with Shortsword-17 are equally good at smiting foes, regardless of whether their skill is due to talent or training. However, there are times when you need (or want) to know the difference.

It is easy to compare talent - just look at the controlling attribute for the skill. In the example above, the DX 17 swordsman is clearly more talented than the DX 10 fighter.

To compare training, you must look at relative skill level. You can calculate it quickly by subtracting controlling attribute from skill level. In our example, the DX 17 warrior has a relative skill level of 0, while the DX 10 fighter has a relative skill level of +7, and is better trained.

Relative skill level becomes important when using the next two rules; therefore, you might opt to note it in parentheses after your skill level; e.g., "Shortsword-17 (+7)."

===== Using Skills With Other Attributes =====

The GM will sometimes find it useful to ask for a skill roll based on an attribute other than the controlling one for a skill. This is realistic; few skills really depend just on brains, just on agility, etc. To make a roll like this, simply add the relative skill level to the attribute you wish to use and make a success roll against the total.

Example: A warrior with DX 10, IQ 14, and Shortsword-17 has a relative skill level of +7 in Shortsword. If the GM asked for an IQ-based Shortsword roll, the swordsman would roll against 14 + 7 = 21 instead of his Shortsword skill of 17.

Some skill descriptions present situations where skill rolls using other attributes would be appropriate. The GM is encouraged to dream up more! A few examples:

-- DX-based rolls against IQ-based repair skills to reach into tight corners; ST-based rolls against these skills to manhandle engine blocks and other heavy parts into place.
-- IQ-based rolls against DX-based combat skills to feint an opponent, formulate tactics, or perform minor maintenance on weapons; ST-based rolls against these skills to disarm someone using brute strength rather than finesse.
-- IQ-based rolls against DX-based vehicle operation skills to recall traffic regulations, remember to change the oil, or identify the make and model of a vehicle; HT-based rolls against these skills to stay awake at the wheel.

Your relative skill level will sometimes modify ST for a specific task (e.g., kicking in doors.) Only modify ST if your relative skill level is positive - you get a bonus for high skill, but you never get a penalty for low skill.

===== Using Skills Without Attributes =====

The GM might occasionally want two people with identical training to have similar odds of success regardless of their attributes, in a situation where training really does matter more than innate talent. In this case, just add relative skill level to a flat number - usually 10 - and roll against the result.

Example: Two accountants are vying for a promotion. One is talented, with IQ 14 and Accounting-18 (+4). The other is dull but experienced, with IQ 8 and Accounting-15 (+7). The GM decides to handle this as a Quick Contest; each accountant must attempt his Accounting roll, and the one who succeeds by the most will get the promotion. However, the boss cares about seniority above all, so the GM applies relative skill level - which reflects experience - to a flat base of 10. This leaves IQ out of the picture! The talented accountant rolls against 10 + 4 = 14, while his rival rolls against 10 + 7 = 17. Sometimes, life isn't fair...

===== Skill Defaults: Using Skills You Don't Know =====

Most skills have a 'default level': the level at which you use the skill if you have no training. A skill has a default level if it is something that everybody can do... a little bit. As a general rule, a skill defaults to its controlling attribute at -4 if Easy, -5 if Average, or -6 if Hard. There are exceptions to this, but not many.

Example: The 'default' for Broadsword (DX/Average) is DX-5. If your DX is 11, and you have to swing a broadsword without training, then your 'default' skill at Broadsword is 11 - 5 = 6. You need a roll of 6 or less to hit.

Some skills have no default level. For instance, Alchemy, Hypnotism, and Karate are complex enough that you cannot use them at all without training.

Regardless of your default skill level, you do not get the special benefits of a skill - especially combat bonuses such as improved damage, special defenses, and unpenalized off-hand use - when you use a skill at default. To enjoy these benefits, you must spend at least one point on the skill.

===== The Rule of 20 =====

If a skill defaults to a basic attribute that is higher than 20, treat that attribute as 20 when figuring default skill. Superhuman characters get good defaults, but not super ones.

===== Who Gets a Default? =====

Only individuals from a society where a skill is known may attempt a default roll against that skill. For instance, the default for Scuba skill assumes you are from a world where scuba gear exists and where most people would have some idea - if only from TV - of how to use it. A medieval knight transported to the 21st century would not get a default roll to use scuba gear the first time he saw it!

===== Defaulting to Other Skills =====

Some skills default to another skill instead of or as well as an attribute.

Example: Broadsword defaults to Shortsword - 2, because the two skills are very similar. A Shortsword skill of 13 gives you a 'default' Broadsword skill of 11.

===== Double Defaults =====

A skill can't default to another skill known only by default. If Skill A defaults to Skill B - 5, and Skill B defaults to IQ - 5, does Skill A default to IQ - 10? No.

===== Improving Skills from Default =====

If your default level in a skill is high enough that you would normally have to pay points for that level, you may improve the skill past its default level by paying only the difference in point costs between your new level and your default level.

Example: Suppose you have DX 12 and Shortsword at 13. Since Broadsword defaults to Shortsword - 2, your default Broadsword skill is 11. Skill 11 is equal to DX - 1 for you. This would have cost 1 point had you bought it directly. The next level (DX) costs 2 points. The difference is 1 point; to raise your Broadsword skill from its default level of 11 (DX - 1) to 12 (DX), you need only pay 1 character point. You do not have to pay the full 2 points for DX level!

If you increase a skill, skills that default to it go up as well. However, if you have spent points to improve these defaults, you may not see an increase when you raise the skill to which they default. This is best illustrated with our running example:

Example: Suppose you spend the point to raise Broadsword to 12 (DX). Now you spend 4 more points on Shortsword, improving that skill from 13 to 14 (from DX + 1 to DX + 2). Does your Broadsword skill also go up a level? No. Your new default from Shortsword is now 12  (Shortsword at 14, minus 2), but to go from level 12 to level 13 (from DX to DX + 1) with Broadsword costs 2 points, and you've only spent 1 point on Broadsword. Keep track of that point, though. When you spend one more point on Broadsword, it goes up a level, too.

When two skills default to one another and you have improved both, you may switch the 'direction' of your default if this would give you better skill levels. Redistribute the points spent on both skills as needed. You may never decrease either skill level this way, however; you must always spend enough points to keep each skill at its current level.

Example: Keeping Shortsword at 14, you spend a total of 22 points on Broadsword, improving your skill from its default of 12 (DX) to 18 (DX + 6). You'd like to default Shortsword from Broadsword now, rather than vice versa. Taking the 8 points you spent on Shortsword and the 22 points you spent on Broadsword, you have 30 points to work with. First, buy Broadsword at 18 (DX + 6) for 24 points. Then default Shortsword from Broadsword, getting 16 (that is, Broadsword - 2). Finally, spend the remaining 6 points on Shortsword. This will be enough to raise Shortsword skill to 17 (and 2 more points will make that 18.)

This feels like an abstract number shuffle, but it works. You're no better off than if you had started out with Broadsword skill, and you aren't penalized for learning Shortsword first.

Now that you understand skills, take a look at the [[:rpg:gurps:core:skill_list|Skill List]] or look through the [[:rpg:gurps:core:skill_modifiers|Skill Modifiers]]...