I’ve never really liked the way opposed rolls work in 3.5 Edition D&D. Since both players are rolling, it effectively doubles the range of the results you can wind up with, making it more variable than I’d like. Looking at Pathfinder and 4E D&D, it looks like other people felt the same way, as both of those systems eliminated or greatly reduced the prevalence of opposed rolls.
My Solution :
(informed by the 2 aforementioned sources)
Whenever an opposed roll is called for by the rules the two parties involved are designated either “Passive” or “Active”. Generally, an Active character is the one taking an action at the time, and so characters are usually only Active on their turn. The Passive character then, is the one being acted upon. For Example, when someone makes a check to grapple you, you are Passive, and when you try to escape the grapple you become Active and the Grappler is Passive.
Active characters roll as normal for the check, but Passive characters do not -they are instead assumed to roll a 10 for their check, along with all modifiers they would normally get.
This is pretty straight-forward for combat maneuvers like Grapple, Trip, and Bull Rush (the attacker is active, the defender is passive), but things get a little more complicated with other opposed checks, like Stealth v. Perception or Sense Motive v. Bluff.
A character attempting to sneak tests against the target’s passive score, as described above, in most cases. However, if a character spends a move action to actively scan their surroundings, they may immediately make a perception check against a sneaking character’s passive stealth score (often with a terrain or concealment bonus). In addition, the perception check rolled is used as the passive score for all Stealth checks against that character.
Example: Two goblins are trying to sneak up on the party’s camp at night, with Stealth modifiers of +12. Kaneda is standing guard with his nose in a book, and his Perception Bonus is +8. The goblins move into position and attack with their shortbows, rolling a 19 and a 24 on their Stealth Checks against Kaneda’s passive Perception of 18 (10 + his usual bonus of 8). One of them scrapes his dagger against a rock, and Kaneda goes on the defensive. He spends an action to roll a good Perception check on his turn, scoring a 23 -one of the goblins is more concealed behind a rock than his friend, so Kaneda only spots the one on the right. To finish his turn, Kaneda flings a magic missile at the little beast and wounds him. Realizing that he’s been seen the wounded goblin rushes in to attack the Illumian, while his ally stays hidden, hoping to outflank Kaneda. The hidden Goblin makes a stealth check as he moves and gets a 21, this would normally have beaten Kaneda’s passive score, but because he used an Active Perception check on his turn the goblin is testing against the 23 instead. Kaneda can now see both of the Goblins.
Similar to Stealth, Bluff is tested against the target’s Passive defense unless the target specifies that they using Sense Motive (and has a compelling in-game reason to do so). If the target is testing Sense Motive, the rolls are opposed as usual. Since conversation is a free action, Sense Motive does not require an action to use.
Example 1: Merrilyn is chatting up a woman at the Lonesome Jug. He has a Bluff Check of +10, and decides to embellish the details of the party’s last exploit to impress her. She has little reason to suspect he is lying, and it doesn’t really affect her anyway, so she does not scrutinize his story. He tests against her Passive Sense Motive of 12 and is unsurprisingly successful. She swoons.
Example 2: Brundle is trying to track down a goon who has been pushing Arcanite at the University; working on a tip from his niece, he talks to the creepy janitor. The man claims he doesn’t know anything, but Brundle trusts Peony so he declares that he is using Sense Motive. They make opposed rolls and Brundle easily beats the janitor’s roll, 28 to 19. He presses the subject and the janitor cracks, admitting that he is a bagman for one of the dealers on campus.
There are no doubt other situations where an opposed roll might be more applicable than passive tests; we will deal with those as they come up.