Friday, April 20, 2012

Fixing Passive Perception in 4e

Passive Perception isn't a bad idea in and of itself. It has a lot going for it, actually. It is nostalgic, originating from old school versions of the game, where certain races had a chance to notice hidden doors and the like, simply by passing by them. Using passive skills also rewards players who deliberately spend resources to improve and excel at a skill. Lastly, it can, in some instances, save the DM some time, as he doesn't have to call for a check. But somewhere along the way it all went wrong. In this post, I am looking at what the problem is with Passive Perception (and other passive skills to some extent), and how to fix it.

So what is the problem in the first place? Well, to put it as simply as possible, it is hard to threaten 4e PCs with traps using it. Even casual, unoptimized groups can produce a PC whose Passive Perception is consistently above the moderate difficulty check, and often even a hard check. It is too easy. I want players to explore their environment and not have everything handed to them automatically. So here are my ideas on how to make it better:

Always use the hard DC
I want most hidden traps to be hard to detect. Note I said most. Otherwise, there's not much point in hiding them. I mean, sure I want to reward players for spending feats and such to help boost their skills, but the bottom line is some groups skills are so high they will always beat DCs; so here is what I recommend for DCs. Well-constructed traps can only be detected passively by a PC with a score better than, or equal to, the hard DC of the trap's level. Note that you will still have players that beat these DCs passively, and that's ok. If a trap is of poor quality or obvious, use the moderate DC of the trap's level. There are a few times that I would encourage the use of a lesser quality trap. Maybe for flavor reasons, or when using traps in an already difficult encounter, or to lull the players into a false sense of security regarding their skills.

Limit a PCs ability to rely on passive skills
This one has an old-school vibe. If a PC rolls an active check, use that check until they leave the area; they no longer qualify for their passive scores while in that area. So say they announce they are looking for traps and roll a 2. Do not let their score suddenly improve while they are still in the rough area. You can even call it ten minutes, or a 'turn'. Let players know this when they roll an active check to search.

Use skills other than Perception
Flavor your traps with different detection requirements. Maybe Perception doesn't work on some of them; they require Dungeoneering training. Or there might be an old holy symbol that is plainly visible to all, but it takes skill in Religion to automatically recognize it is trapped.

Reward exploration
The obvious flip-side of all of this talk of torturing PCs is to reward exploration when deserved. This is the kind of think that doesn't necessarily fit the codified rules approach of 4e, but occasionally, if you have a group of adventurers that are showing caution, playing attention to clues, and roleplaying, and they make a group check and fail, consider giving them a bonus to their check, or an automatic success. Don't do this every time, as some players might feel patronized or insulted; rely on 'feel' to tell you when this is appropriate. This is basically "taking 20" with conditions added.

Experiment with an alternate approach
If you still hate passive skills, you could just try something completely different. Another way to do it is to require a moderate or hard DC to even qualify to detect a trap. The DM then rolls a hidden roll to determine if the qualifying PC notices the trap. In other words, their Passive Perception allows them a chance to detect it, but doesn't guarantee success. This is kind of like an old school game, like an Elf determining a hidden door without trying on the DMs roll of 1 or 2 in 6. If a PCs passive score is high enough to beat the moderate DC to detect the trap, make a hidden percentage dice roll. The PC has a 75% chance to notice a trap of average construction, and a 50% chance to notice a well-constructed trap. This method adds an extra chance of failure on the back end. This method increases the threat of the trap while giving you an added old-school vibe.

In summary, I really don't want to come off too harsh. I just want to reward actual exploration and make passive trap detection more difficult. These ideas put power back into the DMs hands and make traps more dangerous than those in the typical game of 4e.

As always, I am interested in your feedback and opinions. Do you have your own method for using Passive Perception? Leave a post!


  1. I like it. As much as I love 4e, the Passive skills always struck me as just... lazy. Aside from just outright banning Passive skills, I think this article offers a very good alternative to the RAW.

  2. Passive checks aren't made for everything. A Passive check is the equivalent of "Taking 10" from older editions on skills, as such, it requires a reasonable time exposed to some things before you just notice them. If someone hangs around for 5-10 mins near a trap without triggering it and their Passive Perception would detect it according to the DC I set (I don't use the chart, I set my own) then I may weave something into my narrative that might hint there is a trap nearby and inspire active checks. Otherwise, I use Passive Perception to determine, without having to have people roll, who might notice an errant smell on the breeze, or even the fact that there is a breeze in a cave that slightly comes from the North.

    When I describe a new encounter area (or any new area mostly, so that they don't automatically clue in that heavy description means something's up) I look at my PCs' Passive Perception scores and according to those scores, I will single out individuals that notice extra things. If I mention that "the cave is overwhelmed with the smell of limestone and mildew from the walls dripping water, forming stalagtites and stalagmites throughout the chamber, some forming together into calicites" I may tell the character with the 22 Passive Perception via a note or something "you also detect the faintest smell of copper or iron, just beneath the surface of the mildew smell...putting you in mind of a slaughterhouse" thus cluing in to that PC that there is something else there that his keener senses help him with.

    Finding traps, searching puzzles for clues, things like that require active checks. Also, depending on the puzzle, it may not be perception that is needed. If your examining a magically locked chest for traps, there may not be any truly mundane indicators that its trapped at all, however, while doing this passive search...I may consult your Passive Arcana (add 10 to Arcana) since you are actively searching, if your trained...and if its good enough, I'll indicate "There doesn't appear to be any kind of trap or anything within the chest's lock, however, when you run your hands over the wood, the hairs on the back of your neck stand up and you get a slight whiff of ozone in the air...a cloying almost acid taste at the back of your throat"

    Seuss (lordseussmd on YM)

  3. good stuff, very flavorful. i like how you are using passive skills to determine the way you describe something; it adds an extra layer of improvisation for the dm. thanks for the post!

  4. Its all about painting the picture and immersion for Me!