Tuesday, June 4, 2013

The Skill Score

This is a skill system.  I tried to design something that was as beautifully simple as the "roll-under" method and would integrate seamlessly with it.

Skill scores are treated like backup ability scores.  They have a (soft) maximum of 18, the same as ability scores.  When you attempt a skill, you roll the skill die AND the ability score die.  If either of them succeed, the attempt succeeds.  If they both succeed, the attempt is a double success, and good things happen. (The action is faster/quieter/reversible/etc or an ally gets a bonus on the same check).


Alice has 10 Dexterity.  Tip-toeing silently through a courtyard full of dead leaves requires her to roll a 10 or lower on a d20 roll.

Bob has 10 Dexterity and 8 Move Silently.  When he attempts to move through the same courtyard, he rolls two dice at the same time.  If his ability die is 10 or lower, he succeeds.  If his skill die is 8 or lower, he succeeds.  If both of the rolls succeed, Bob is even able to sweep a couple of cobblestones free of leaves, making it easier for Charlie, coming along behind him.

Modifying Difficulty
Easy/Hard: Treat the ability and skill scores as if they were 2 points higher/lower.
Really Hard: Treat the ability and skill scores as if they were 1/2 their current value.
Experts Only: Anything less than a double success is a failure.
Really Technical: Only roll the skill die.  Only experience can help you now.

Opposed Checks
Opposed parties roll their ability die and their skill die (if they have one).
Whoever has more successes wins.
In case of a tie, whoever has the highest number wins.

Generating Skill Scores
This is the chunky part.  I have some ideas about how to best do this, but I'll save that for a different post.  But if you want to convert X-in-6 to a skill score, then: 1-in-6 becomes 3, 2-in-6 becomes 7, 3-in-6 becomes 10, 4-in-6 becomes 13, and 5-in-6 becomes 17.

Closing Thoughts
The nice part about this is that both ability score and skill contribute equally to success.  And a lower a PC's ability score is, the more they gain by taking some training in a related skill.  But even if you have 18 Strength, you still might want some Climibing skill, because double successes are very nice.  And it naturally caps at 18/19, so there is no temptation to indulge in infinitely increasing DC silliness, a la 3.x.

Are there other systems that use something like this?  Scrap Princess had a sorta-similar something a little while ago, but I can't find any others.

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