A skill check takes into account a character's training (skill rank), natural talent (ability modifier and luck (the die roll). It may also take into account his or her race's knack for doing certain things (racial bonus) or what armor he or she is wearing (armor check penalty), or a certain feat the character possesses, among other things. For instance, a character who has the Skill Focus feat related to a certain skill gets a +3 bonus on all checks involving that skill.
To make a skill check, roll 1d20 and add your character's [[skill] modifier for that skill. The skill modifier incorporates the character's ranks in that skill and the ability modifier for that skill's key ability, plus any other miscellaneous modifiers that may apply, including racial bonusesand armor check penaltys. The higher the result, the better. Unlike with attack rolls and saving throws, a natural roll of 20 on the d20 is not an automatic success, and a natural roll of 1 is not an automatic failure.
Untrained Skill Checks:
Generally, if your character attempts to use a skill he or she does not possess, you still make a skill check as normal. The skill modifier doesn't have a skill rank added in because the character has no ranks in the skill. Any other applicable modifiers, such as the modifier for the skill's key ability,are applied to the check.
Many skills can be used only be someone who is trained in them. If you don't have Spellcraft, for example, you just don't know enough about magic even to attempt to identify a spell, regardless of your class, ability scores, or experience level. Skills that cannot be used untrained are indicated in their skill descriptions.
For example, Krusk the [[barbarian's 4 ranks in Climb make his climb check results 4 points higher than they otherwise would be, but even Gimble the bard, with no Climb ranks, can make a Climb check because Climb can be used untrained. Gimble has a skill modifier of -1 (+0 for his strength, -1 for armor), but he can give it a try. However, Gimble's ranks in Use Magic Device let him do something that he otherwise couldn't do at all - namely, use a magic item as if he had a particular spell on his class spell list that he actually doesn't have. Krusk, with no ranks in the skill, can't makke a Use Magic Device check even at the penalty because Use Magic Device can not be used untrained.
Favorable and Unfavorable Conditions
- Some situations may make a skill easier or harder to use, resulting in a bonus or penalty to the skill modifier for a skill check or a change to the DC of the skill check.
- The chance of success can be altered in four ways to take into account exceptional circumstances.
- 1. Give the skill user a +2 circumstance bonus to represent conditions that improve performance, such as having the perfect tool for the job, getting help from another character (see Combining Skill Attempts), or possessing unusually accurate information.
- 2. Give the skill user a –2 circumstance penalty to represent conditions that hamper performance, such as being forced to use improvised tools or having misleading information.
- 3. Reduce the DC by 2 to represent circumstances that make the task easier, such as having a friendly audience or doing work that can be subpar.
- 4. Increase the DC by 2 to represent circumstances that make the task harder, such as having an uncooperative audience or doing work that must be flawless.
- Conditions that affect your character’s ability to perform the skill change the skill modifier. Conditions that modify how well the character has to perform the skill to succeed change the DC. A bonus to the skill modifier and a reduction in the check’s DC have the same result: They create a better chance of success. But they represent different circumstances, and sometimes that difference is important.
Time and Skill Checks
- Using a skill might take a round, take no time, or take several rounds or even longer. Most skill uses are standard actions, move actions, or full-round actions. Types of actions define how long activities take to perform within the framework of a combat round (6 seconds) and how movement is treated with respect to the activity. Some skill checks are instant and represent reactions to an event, or are included as part of an action.
- These skill checks are not actions. Other skill checks represent part of movement.
Practically impossible Tasks
Sometimes you want to do something that seems practically impossible. In general, a task considered practically impossible has a DC of 40, 60, or even higher (or it carries a modifier of +20 or more to the DC).
Practically impossible tasks are hard to delineate ahead of time. They’re the accomplishments that represent incredible, almost logic-defying skill and luck. Picking a lock by giving it a single, swift kick might entail a +20 modifier to the DC; swimming up a waterfall could require a Swim check against DC 80; and balancing on a fragile tree branch might have a DC of 90. The DM decides what is actually impossible and what is merely practically impossible. Characters with very high skill modifiers are capable of accomplishing incredible, almost unbelievable tasks, just as characters with very high combat bonuses are.
Checks without Rolls
- A skill check represents an attempt to accomplish some goal, usually while under some sort of time pressure or distraction. Sometimes, though, a character can use a skill under more favorable conditions and eliminate the luck factor.
When your character is not being threatened or distracted, you may choose to take 10. Instead of rolling 1d20 for the skill check, calculate your result as if you had rolled a 10. For many routine tasks, taking 10 makes them automatically successful. Distractions or threats (such as combat) make it impossible for a character to take 10. In most cases, taking 10 is purely a safety measure —you know (or expect) that an average roll will succeed but fear that a poor roll might fail, so you elect to settle for the average roll (a 10). Taking 10 is especially useful in situations where a particularly high roll wouldn’t help.
When you have plenty of time (generally 2 minutes for a skill that can normally be checked in 1 round, one full-round action, or one standard action), you are faced with no threats or distractions, and the skill being attempted carries no penalties for failure, you can take 20. In other words, eventually you will get a 20 on 1d20 if you roll enough times. Instead of rolling 1d20 for the skill check, just calculate your result as if you had rolled a 20.
- Taking 20 means you are trying until you get it right, and it assumes that you fail many times before succeeding. Taking 20 takes twenty times as long as making a single check would take.
Combining Skill Attempts
When more than one character tries the same skill at the same time and for the same purpose, their efforts may overlap.
Often, several characters attempt some action and each succeeds or fails independently.
For example, Krusk and each of his friends needs to climb a slope if they're all to get to the top. Regardless of Krusk's roll, the other characters need successful checks, too. Every character makes a skill check.
You can help another character achieve success on his or her skill check by making the same kind of skill check in a cooperative effort. If you roll a 10 or higher on your check, the character you are helping gets a +2 bonus to his or her check, as per the rule for favorable conditions. (You can't take 10 on a skill check to aid another.) In many cases, a character's help wont be beneficial, or only a limited number of characters can help at once. The DM limits cooperation as he or she sees fit for the given conditions. For instance, if Krusk has been badly wounded and is dying, Jozan can try a Heal check to keep him from loosing more Hit Points. One other character can Help Jozan. If the other character makes a Heal check against a DC 10, then Jozan gets a +2 circumstance bonus on the Heal check he makes to help Krusk. The DM rules that two characters couldn't help Jozan at the same time because a third person would just get in the way.
In cases where the skill restricts who can achieve certain results (such as with Disable Device, Search and Survival), you can't aid another to grant a bonus to a task that your character couldn't achieve alone. For instance, a character who doesn't have the trapfinding class feature can't use Search to help a rogue find a magic trap, since the helper couldn't attempt to find the magic trap on his own.