D&D 5E Perception vs Investigation

[iserith]

yeah, that it's dull, that's what bothers me. And I think there's the constant expectation of "I can't be surprised." The high perception DC becomes a zone/aura of protection around them at all times.

It sounds like the check is being overused at your table - it's not a radar that's always on. Just remember that if they're doing just about anything other than keeping an eye out for danger or if they are not in the physical position to notice something, their passive Perception cannot be used to detect hidden threats. So if one of the PCs is in the back of the marching order while the other one is adjusting the map of the dungeon at the center of the group, neither of them may apply their passive Perception to avoid surprise from a monster coming from the front of the group. They are just surprised, no check at all.

 

[Nebulous]

It sounds like the check is being overused at your table - it's not a radar that's always on. Just remember that if they're doing just about anything other than keeping an eye out for danger or if they are not in the physical position to notice something, their passive Perception cannot be used to detect hidden threats. So if one of the PCs is in the back of the marching order while the other one is adjusting the map of the dungeon at the center of the group, neither of them may apply their passive Perception to avoid surprise from a monster coming from the front of the group. They are just surprised, no check at all.

I'm almost positive my players will argue otherwise, that yes, it IS a defensive radar that is always passively active, hence the name. And I could not legitimately say that a monster making noise 20 feet away was not heard by a player with a 19 passive perception, they would complain their heads off, regardless of the marching order. Now if i roll higher than the DC, or the DC is a 20+ (which is uncommon in 5e) then it's acceptable.

The game, for better or worse, legitimately allows them to build characters with that ability, but the skill section fails to offer adequate examples and explanations.

Of course I as DM have final say on when and where and how such checks are made, but if i'm not following the model set by the rules then they're not going to like it. If the PHB had specific examples of the players being surprised while adjusting the map, that would be cool, we could use that as a reference point for adjudication.

Edit - it's not as bad as I'm making it sound, but after 6 months of running 5th edition we're not happy with how skills work.

 

[iserith]

I'm almost positive my players will argue otherwise, that yes, it IS a defensive radar that is always passively active, hence the name. And I could not legitimately say that a monster making noise 20 feet away was not heard by a player with a 19 passive perception, they would complain their heads off, regardless of the marching order. Now if i roll higher than the DC, or the DC is a 20+ (which is uncommon in 5e) then it's acceptable.

The game, for better or worse, legitimately allows them to build characters with that ability, but the skill section fails to offer adequate examples and explanations.

Of course I as DM have final say on when and where and how such checks are made, but if i'm not following the model set by the rules then they're not going to like it. If the PHB had specific examples of the players being surprised while adjusting the map, that would be cool, we could use that as a reference point for adjudication.

Edit - it's not as bad as I'm making it sound, but after 6 months of running 5th edition we're not happy with how skills work.

Consider that "passive" in "passive check" doesn't refer to not actively doing something - it refers to there being no roll. (Basic Rules, page 59: "...the average result for a task done repeatedly...") Then you just treat it like any other check, which is to say, the DM decides when it comes into play - when the action they have taken has an uncertain outcome.

Also, see Basic Rules, pages 64-65, especially "Noticing Threats:"

"Characters who turn their attention to other tasks as the group travels are not focused on watching for danger. These characters don’t contribute their passive Wisdom (Perception) scores to the group’s chance of noticing hidden threats. However, a character not watching for danger can do one of the following activities instead, or some other activity with the DM’s permission."

As you can see, it's meant to be a trade off. You're either keeping alert for hidden threats or doing something else. Also:

"The DM might decide that a threat can be noticed only by characters in a particular rank. For example, as the characters are exploring a maze of tunnels, the DM might decide that only those characters in the back rank have a chance to hear or spot a stealthy creature following the group, while characters in the front and middle ranks cannot."

Passive Perception just ain't the I-win radar that many people think it is...

 

[Ristamar]

A passive Perception score of 19 is impressive. Such a person shouldn't be surprised very often, at least not by something relatively mundane.

Regardless, in a moments notice, an individual's perception is not a protective blanket for the entire party. There are plenty of circumstances where less aware PCs can be caught off guard and unable to act immediately, while the more perceptive individuals are not surprised.

 

[Nebulous]

Passive Perception just ain't the I-win radar that many people think it is...

I'll definitely keep it in mind, thanks. And the "I-win-radar" is a great way to put it.

 

[77IM]

I've never understood Perception being a skill only a few classes have access to. I prefer games that consider Perception an innate part of the character. I don't think anyone could survive for long as an adventurer without Perception as it is used in D&D. I'm going to make it available to everyone.

I've often thought it would have been better for Perception to be a derived stat just like Initiative: for most people, it's just equal to an ability score, but a few classes/races/feats get to add some amount of proficiency bonus to it. For example, maybe Rangers and Rogues add their full proficiency to Perception, and Bards and Fighters and Monks and Trickster Clerics add half. And maybe Fighters and Rogues add their full proficiency to Initiative, while Bards and Monks and Rangers and War Clerics add half. Just spitballing here -- it would make Initiative a little more interesting, and make Perception less of a must-have skill (since if you don't have it, it's hard to get it, since it's not a skill). And then a feat that grants you full Proficiency bonus to Perception and/or Initiative, plus some other goodies, becomes a reasonable feat purchase for someone who really really wants their Wizard or Moon Druid or Barbarian or whatever to become extra alert.

 

[77IM]

Passive Perception just ain't the I-win radar that many people think it is...

Another trick that is used a lot in Lost Mine of Phandelver: often the passive DC is 5 points higher than the active DC. Many secret doors and such can be found with a DC 10 Perception check, or a Passive Perception of 15 or better. (If you want a game-mechanical justification, you could say that a carefully hidden object or carefully set ambush has advantage against someone who isn't actively suspicious.)

 

[iserith]

Another trick that is used a lot in Lost Mine of Phandelver: often the passive DC is 5 points higher than the active DC. Many secret doors and such can be found with a DC 10 Perception check, or a Passive Perception of 15 or better. (If you want a game-mechanical justification, you could say that a carefully hidden object or carefully set ambush has advantage against someone who isn't actively suspicious.)

I think this just goes to show the designers' inconsistency on the matter. A passive check resolves uncertainty in the outcome of a task that a character is performing again and again such as looking for secret doors. That is the character actively doing a thing. The check is the thing that is passive in that there is no roll.

So why then is the DC for finding the door here any different? The task is basically the same - searching for secret doors - only in one case the character is searching over and over again and in the other case the character is searching once. In the former, the player is trading time for an average result on the die. In the latter, the player is trading nothing and taking a shot at potentially rolling lower or higher. If the player wants to trade 10x the amount of time it normally takes to find a secret door, then the character may automatically succeed (DMG pg. 237).

The designers are really all over the place on this one and it's causing some confusion. However, I still think it's not critical to get it exactly right in the grand scheme of things.

Edit: As an aside, this is why you sometimes want time to be a limited resource for the PCs. The easiest way is to create a countdown to Bad Stuff or use wandering monster checks. It's fun and challenging to have to make these trade-offs.

 

[Tony Vargas]

I think this just goes to show the designers' inconsistency on the matter. A passive check resolves uncertainty in the outcome of a task that a character is performing again and again such as looking for secret doors. That is the character actively doing a thing. The check is the thing that is passive in that there is no roll.

So why then is the DC for finding the door here any different?

How certain are you that passive is used only to represent a repeated task, rather than 'just noticing' something even if you're not actively looking? Because in the latter context, the different difficulty makes sense, just like the old-school modules where there were no perception checks, and a feature would be obvious, found some % of the time, or found only when a player described exactly the right actions in searching for it (possibly, again, only on some arbitrary roll, even then). Just, now, we have a consistent die mechanic instead of finding one thing being a 2 in 6 and another 33 on d% for no particularly reason.

The logical results of the DC for an active search being lower, of course, is to 'actively' search everything all the time...

 

[iserith]

How certain are you that passive is used only to represent a repeated task, rather than 'just noticing' something even if you're not actively looking? Because in the latter context, the different difficulty makes sense, just like the old-school modules where there were no perception checks, and a feature would be obvious, found some % of the time, or found only when a player described exactly the right actions in searching for it (possibly, again, only on some arbitrary roll, even then). Just, now, we have a consistent die mechanic instead of finding one thing being a 2 in 6 and another 33 on d% for no particularly reason.

The logical results of the DC for an active search being lower, of course, is to 'actively' search everything all the time...

Basic Rules, page 59: "A passive check is a special kind of ability check that doesn't involve any die rolls. Such a check can represent the average result for a task done repeatedly, such as searching for secret doors over and over again, or can be used when the DM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster."

So on the one hand we have ourselves a mechanic that says it's for resolving the uncertainty in the outcome of a task that's done repeatedly versus, as in aforementioned the LMoP example, DCs that are set as if the character wasn't doing anything but walking around. Then you have the mechanics for exploration, pages 64 and 65 which show that if you're doing anything other then actively looking out for threats (uncertainty of which is governed by a passive check), then your passive check doesn't get applied when determining if you notice a hidden threat. You're just surprised, or whatever. Going back to the secret door example, if you're repeatedly searching a corridor for secret doors, it's reasonable for the DM to say that you're straight-up surprised by the lurking mimic or or shadow because you weren't repeatedly on the lookout for hidden threats - you were repeatedly doing something else.

This all reads to me like the designers are not on the same page with how this works. Or they designed it this way so some tables could treat it like radar and other tables could treat it like any other check. (I'm not sure I'm willing to give them the benefit of the doubt on the latter even if it happens to work with the "Do whatever" paradigm.)