Passive skill checks - can someone explain them?

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I am running a 4e game, and I have my PC's passive perception and passive insight written down. But I am not 100% sure on how to use them. The word passive throws me; am I still supposed to roll a d20 + the passive skill score? Or should I take the score and compare to the DC? A paladin in the group has 21 in passive Insight (or perception I forget) at lvl 2 - is that normal?

I know this is a really basic question, but I hope someone will help me out here.

They're called passive because you don't roll them at all.  The numbers for Passive Perception and Insight serve as target numbers for skill use when the character in question is not actively looking for something/scrutinizing someone.

A 21 passive insight for a L2 paladin sounds feasible.  10 base, +5 Trained, +3 Wisdom, +1 half-level, +2 racial or background bonus.
They're called passive because you don't roll them at all.  The numbers for Passive Perception and Insight serve as target numbers for skill use when the character in question is not actively looking for something/scrutinizing someone.



thank you for setting that straight. Though I am still not sure how to really use them - you say you use them as target numbers - for what? Can you give me an example?


You attempt to sneak past someone who isn't actively keeping guard, just sort of hanging around.  You roll your Stealth check, and compare it to his Passive Perception score.  if your roll meets or exceeds his Passive Perception, you have avoided detection.
You attempt to sneak past someone who isn't actively keeping guard, just sort of hanging around.  You roll your Stealth check, and compare it to his Passive Perception score.  if your roll meets or exceeds his Passive Perception, you have avoided detection.



Thank you! Good example. But this raises another issue - if a player has 21 in his passive perception, and he's in a dungeon where he is in the vicinity of a gem, and he is not actively searching for anything - how should I handle that?


If you think he ought to find it, he should find it, no check required (or, if there must be mechanics, its stealth < his passive perception, not that objects have stealth.  If you think he NEEDS to find it, but it should be challenging, you give some indication that there's something to look for, and run it as a brief skill check/challenge.

Don't make problems where there are none, basically.  If he wants to look for stuff, and nothing important rides on his finding it, he should find it.
Harrying your Prey, the Easy Way: A Hunter's Handbook - the first of what will hopefully be many CharOp efforts on my part. The Blinker - teleport everywhere. An Eladrin Knight/Eldritch Knight. CB != rules source.
If you think he ought to find it, he should find it, no check required (or, if there must be mechanics, its stealth < his passive perception, not that objects have stealth.  If you think he NEEDS to find it, but it should be challenging, you give some indication that there's something to look for, and run it as a brief skill check/challenge.

Don't make problems where there are none, basically.  If he wants to look for stuff, and nothing important rides on his finding it, he should find it.




I use passive perception a lot in my games - to see enemies in the corner of your eyes or in the distance - to overhear conversations - to spot a deer running by in the dark forest - basically, perception is a key skill for my game. Until now, I've asked players to make active rolls for perception when I want to know if they saw something or not. Can passive perception help me there, or do I have to ask the players to make a roll every time I want to know if they spotted something useful?


A real life RPG example from our last session: One of the players sneaked close to a group of elves, hiding in bushes, He couldn't get close to them, so I asked him to make a perception roll to determine how much he could see. He rolled well, and I told him they were wearing leather armor, some had bows, others had swords. If he had failed the perception roll, he would have less information to go on.



Passives certainly can help - but in the end, you'd be setting the DCs anyway, and I'd presume that as a DM, you'd know your players' passives, so essentially, you're deciding if they see a given thing anyway.

You can use them, if they seem reasonable.  In general, I would use them if the PCs are not actively looking for something.

But make no bones about it; you are making the decision as DM, as to whether or not they work, one way or the other.
Harrying your Prey, the Easy Way: A Hunter's Handbook - the first of what will hopefully be many CharOp efforts on my part. The Blinker - teleport everywhere. An Eladrin Knight/Eldritch Knight. CB != rules source.
The other benefit of using Passive Perception and Insight is that you aren't asking the player to make a die roll, so you aren't tipping him off that there's something there that his character might have missed.  Just write down all the PCs' Passive scores and roll against them (this works better if you roll some d20s ahead of time and write down those results, too, since rolling dice will also potentially tip off the players that something is up).
The other benefit of using Passive Perception and Insight is that you aren't asking the player to make a die roll, so you aren't tipping him off that there's something there that his character might have missed.  Just write down all the PCs' Passive scores and roll against them (this works better if you roll some d20s ahead of time and write down those results, too, since rolling dice will also potentially tip off the players that something is up).



Okay, I still don't get how the passive check works. If a paladin has 21 in passive perception, how do I go about using that number? Let's say that the player is passing quickly by a painting on the wall with a picture of the main villain, not looking for clues. He has 21 in PP. So how do I resolve that passive check?

thanks!



There would be no roll, because the painting is right out in the open in plain view.
There would be no roll, because the painting is right out in the open in plain view.




Okay - could you please walk me through it?

This is what I want: I want a way to check the paladins Perception as he moves by the painting to see if herecognizes the villain in the picture. How do I do that without asking the player to roll a perception check?

Please - walk me through it, step by step.


Step 1: "You see a large painting on the wall.  It's the bad guy you've been chasing for the last week."
There is no Step 2.  You don't have to make a roll or a check for everything.


An actual use of passive perception ... the PCs are standing around, and someone is attempting to dart across the hallway without them noticing.  You (the DM) roll the NPC's stealth check, and compare it to each individual PC's Passive Perception.  If he succeeds, that PC did not notice him.  If he fails, that PC did notice him.

Ok, so passive perception isn't going to work for my game. I think that I will write down their active perception down and simply roll against a DC to see if they see something or not.

And no, I wouldn't make these checks for anything important.

Back to the painting - - you as the DM might have hidden a clue in the painting - like he appears to be holding an unusual looking key which looks familiar. You might set the DC of finding the clue at perception DC 20. The above mentioned paladin will on seing the picture - (passive perception 21) hey that's interesting that key looks familiar. In the case of no one having passive perception high enough - one of the players has to be bright enough to think - why did the DM put a painting here - I'll make a perception check to check it out - needing to get 20 to notice the clue - if the roll(s) fails or noone makes a perception check (and no one has high enough passive) clue is not found. Not all clues need to be found. Of course with critical clues a hint from the Dm is an idea if the players have "lost it". Players can learn and become more competant and interesting roleplayers (two separate developments) - - -etc


Passives are great equivalent to an active check with a die roll of 10. e.g. Many times in our game the high passive perception characters are not surprised by the ambush and the low ones are   
I'll add that it makes things a tad more interesting if the passive perception score alerts the PC that something in the painting (room, forest, etc.) catches his attention (asssuming, as in this example, that the passive score exceeds the DC). Then have the PC make an ACTIVE Perception check to actually notice the pertinent detail (or hidden foe, or trap, or what have you).
Good example for passive insight-
When the PCs don't trust an NPC they say that they roll insight to see if the NPC is lieing.
If the PCs don't suspect anything and don't think to roll insight you would check an NPCs bluff check vs the PCs passive insight.

Story example would be a bandit killing an innkeeper and takeing his place. When the "innkeeper" tells them a fair price for a night stay they are not going to think he's lieing. The passive perception would also be used to notice a blood stain on the bar because they are not activelly looking for clues and searching for secrets in the common room, they just want to buy a beer and go to bed.
The sea looks at the stabillity of the mountian and sighs. The mountian watches the freedom of the sea and cries.
I'll add that it makes things a tad more interesting if the passive perception score alerts the PC that something in the painting (room, forest, etc.) catches his attention (asssuming, as in this example, that the passive score exceeds the DC). Then have the PC make an ACTIVE Perception check to actually notice the pertinent detail (or hidden foe, or trap, or what have you).



This is of course seen in every single detective show ever.
The number of time Jessica from "Murder she wrote" explained that something she heard or saw in the first 15 minutes of the episode seemed wrong but could not tell what until the last 15 minutes is way to high to count.

Elongeted Man Ralph Dibney (DC comics) has the same the thing when his nose twithes and he smells a mystery.
The sea looks at the stabillity of the mountian and sighs. The mountian watches the freedom of the sea and cries.
It sounds like you want to 'lead' your players a little too much.

For instance, in the painting scenario, personally I would just describe the scene. 'You walk down the corridor. On the wall to your right is a painting depicting a man doing some stuff'. I've given the players information and clearly stated something of interest in the corridor. It is up to them if they choose to stop and look at it. If they do say 'I want to take a closer look at the painting' I would then say 'you notice the man in the painting is the villan you are chasing'. As previously stated, if there was a 'hidden clue' in the painting, that would have a DC attached to it, but I would NOT allow passive perception to be used to detect it. The PCs would have to make an active check to have a chance of finding it, otherwise they will just miss it. THeir choice.

The reason for this, is because of the word 'passive'. The way I work it is this.

If the players don't know something is happening (they don't know they are being lied to, or they don't know something is trying to stealth around them) then I make rolls vs their passive skills. This is because the players are NOT being active at the time (they can't because I have given them no cue's as to what is going on). If, however, they ARE being active, so they are saying 'I want to search this chest', then only the active check matters. Even if they have a passive perception of 21, if they roll a 15, the check is 15 and that is what I use their search result. Again, this is because they are being active, and that roll represents how well they performed that particular action.

EXAMPLES

Passive Perception

Players are walking through a forest. They are being stalked by a pack of Wolves that are waiting for a good time to strike. The wolves roll stealth (either one for each wolf or one for the pack, depending on how you want to run it). If any player has higher passive perception than the stealth rolls, I will say to that player 'You notice some movement out of the corner of your eye over to the west'. It is then up to them to take action. They may decide to ignroe it and carry on, in which case I will repeat the process until such time that the wolves attack (with suprise). If they decide to take action, I will let them do what they want. Maybe explore, maybe set traps, maybe make active perception checks. Their active perception checks will be rolled against the previous stealth checks, and if they succeed, they will fully notice one/many wolves.

Passive Insight

Two NPC's in a bar are talking and one is trying to rip the other off and the players happen to overhear the converstaion. The NPC doing the ripping off will roll a bluff check and any player with higher passive insight will be told that they believe the NPC is up to no good. It is then up to the players to take action.

Important Note: When reporting the results of failed checks, BE AMBIGIOUS. If they fail an active insight, don't say 'You don't notice anything special' as players will know that this means 'we failed the check so there might be something up'. Simply tell them 'You believe the man is telling the truth'. This way, they don't know if they succeeded or failed in the check, the only know that they believe he is on the level. Giving players as little meta information as possible will keep them 'in the game' and in character.

Active Perception

A room has a secret door in it. As the players enter the room, they decide to have a close look around. If they roll high enough, they find the door. Simple.

Active Insight

A salesman comes up to the players and says he can sell them a magic elixer that will make them all twice as strong for 1000gp. The NPC, who is obviously a con man, will roll a bluff check. The players to take action. Either walk away, or do an active insight check, or buy the potion. If they do active insight, it will be vs the bluff check. If they succeed, I will say that there is clearly something off about the man and his offer. If they fail, I will tell them they believe he is telling the truth.

General Rule

Use passive skills when players have no cues to go on, and use the passive skills to lead players into making decisions and taking action. Use active skills when players are clearly attentive and activley attempting to achieve something.
Passive Perception and Insight are also the standard DC for stealth and bluff checks. When you make a Stealth check in combat to become hidden, it's against the Passive Perception of each creature in the room.  You are hidden against those whose passive Perception you beat, and are not hidden by those whose passive perception is greater than your stealth check.

  After you're hidden, a creature could then spend a minor action to make an active perception check to find the hidden creature. 
 
   The simple rule of thumb is that if there's no action involved (its a free action), it's a passive check, and is basically taking 10 (although some items might boost only passive checks). If a creature is activetly trying to find something, or discern if someone is lying, or in the middle of a skill challenge, then its an active check.

My DM and me were up in arms over this rule when we first picked up the 4th ed.  Or I should say he didn't understand it like the OP.  How I view it really is what most of said but in basic terms it falls like this.

Passive, anything the character is not actively, currently looking for or doing.

Active, When the player states they are doing something, looking at something or asking something.

As for the picture example its simple.  And what I like to suggest is make it a radius around the painting for the passive to kick in if you’re the kind of table that has players move there tokens around as they search a room.  Say the paladin walks by it and he makes the passive perception DC.  You simply have to say, "Something strikes you as family suddenly but you can’t place your finger on it just yet.  Give them a bit of a vague idea so they start asking more active questions.

as for insight just as simple.  roll a bluff check for the npc as its speaking and if any of the characters  passive insight is higher than ur bluff check then you say he seems rather shifty, or he keeps looking around.   If none of their passive’s are beating your DC unless someone asks to make a insight check or I don’t trust this guy, you don’t have to say a word to them if he's lying to them or not.

There's nothing wrong with rolling the PC's Perception to find out if they see something, but some DMs didn't like this because it meant giving away that something was going on, unless the DM was in the habit of making lots of dummy rolls to cover the real ones. I usually wind up asking for my players' passive scores anyway, but then I don't mind them knowing something's up.

I think passive scores were also meant to get around players feeling like they had to constantly roll Perception and Insight (or Spot, Listen and Sense Motive) to keep from getting ambushed or fooled.

Some DMs don't like to use them because it seems like a giveaway. It's very easy to have a massive Perception score, meaning that the character won't miss a single hidden thing. It's generally not a good idea to have a plot or quest or interesting scene hinge on characters not seeing things, so if one doesn't do that, passive scores don't harm anything. Traps, for instance, can be designed to be dangerous even when they're known.

If I have to ask the GM for it, then I don't want it.