D&D 5E Rules Question - Alert (Feat): +5 vs Advantage

[Joe Liker]

That's fine, but that's also my point. By RAW you use passive perception very rarely. Its primary use is to determine if you're surprised by someone stealthing.

Passive perception is also used to notice traps and secret doors if no one is actively looking for them.

I'm not aware of any general uses for passive Investigation, but I believe some specific cases might pop up in published adventures.

In the interest of saving time, a DM might set a PI threshold to figure out how to open a secret door whose existence is already known. Not much else comes to mind.

 

[keterys]

Passive perception is also used to notice traps and secret doors if no one is actively looking for them.

In some cases, yes. It is becoming increasingly common, in my experience, for adventures to have things like:

Trap Door: This trap door is hidden under the carpet. If someone lifts the carpet, it is obvious, but it is impossible to detect otherwise.

Secret Door: This secret door is activated by pulling the Tome of Openings on its second shelf. Someone specifically examining the bookshelf can tell it is attached to the wall strangely and someone searching the books can find the fake tome.

Ie, passive perception doesn't matter because walking down a hallway or looking over a room are largely useless. You must use your player skills and ability to follow room descriptions to find the place to make your relevant Investigation/Perception checks, and until you do so, no amount of Passive Perception does you any good.

But, yes, it's true; it does help you for random "There's a pit in the middle of the path and someone notices it". Which is helpful in published adventures; if the DM is creating things, he's effectively deciding in advance whether you notice traps or not by setting their DC, which is at least one reason I've seen DMs call for a Perception check instead of using passive. Otherwise they're deciding in advance that the group definitely sees or doesn't see something when they set the DC.

 

[Joe Liker]

But, yes, it's true; it does help you for random "There's a pit in the middle of the path and someone notices it". Which is helpful in published adventures; if the DM is creating things, he's effectively deciding in advance whether you notice traps or not by setting their DC, which is at least one reason I've seen DMs call for a Perception check instead of using passive. Otherwise they're deciding in advance that the group definitely sees or doesn't see something when they set the DC.

In theory, this could certainly be the case, but the DM is not supposed to take the party's exact stats into account when designing his dungeons. He is supposed to set the difficulty according to the trap itself, not who might see it.

Also note that the party's passive Perception scores can change with magic or lighting conditions, so even the DM can't be 100 percent certain what he'll be dealing with when the party gets to the trap.

 

[Psikerlord#]

They are different kinds of bonuses, and somewhat interchangable.

One of the books says for passive perception i think, if you have adv, you instead grant a +5 to the score. So it is probably reasonable to swap a +5 for advantage. Adv will give you more consistent higher rolls, which helps avoiding low outcomes. The +5 is more swingy, with greater possible lows and highs, it kinda bends the bounded accuracy framework, esp if you also have high dex.

You can always add adv to the +5 too. But equally a DM could give someone with adv additional flat bonuses on his initiative roll for some reason.

Balance wise I think it's fine to swap one for the other.

 

[Cernor]

Plus, there are a few effects that actually do give advantage to initiative rolls. I can't remember them off the top of my head, but if you change this feat, you are eliminating the benefit of those other effects.

I know that at 7th level Barbarians get advantage on initiative checks with Feral Instinct, so Alert would be a bit redundant if it was changed to give advantage instead of the bonus. Enhance Ability (Cat's Grace) also gives advantage on Dexterity checks (including initiative). Effects that give disadvantage on initiative checks are also uncommon: the poisoned condition stands out as being probably the easiest way to do so.