D&D 5E Perception vs Investigate

[iserith]

See, that is pretty much how I play it, even I haven't stated that clearly. Obviously if you're doing something else, you're probably going to be too distracted to notice something sneaking up on you. However, if a player hasn't stated they're "watching for danger", but aren't doing something else, beyond walking and a little bit of talking, I still take Passive Perception into account for potential dangers. "Search for secret doors" would be something they would have to declare, and be considered a distraction.

We're on the same page here, though I do specifically ask the players to state they're keeping watch for danger so there are no misunderstandings. It's a safe assumption that's what they're doing if they say nothing otherwise. I'm just extra cautious, plus it opens the door for them to describe what they want to do and how which adds to the emergent story.

And we're talking about you're "UNLESS" sentence there, based on what robus proposed earlier for "bouldering". By setting a DC, the DM has automatically said "Fail" for anyone who's passive score doesn't exceed that. Your getting bludgeoned by boulders. Sorry. You had zero chance. Players would rather roll (or at least, know the DM had to roll) than just be told "you fail". That's exactly my point.

I think it's fine and in line with the rules for the DM to say "Fail" after the player's action declaration when that action has no chance of success given the circumstances. It's fine to set a DC a given player's passive check cannot beat, too, after the action declaration and consistent with previous rulings. What I was driving at is there are some DMs who are always going to rely on the dice to determine success and failure and players in such games quickly learn to ask for the roll no matter how good or bad their ideas are in context. This is discussed in the DMG under "Role of the Dice."

So you're really working back in the 3E "Take 10" concept, just as a DM call, not a player's. I don't get your reasoning of "if there is uncertainty as to the outcome", though. Swinging a sword has an uncertainty of the outcome. Should it be a passive check? It'd definitely make fights go faster.

I still disagree with library research for Int (Investigation) as a passive check. Sure the player effectively will never "roll" less than a 10. He will also never roll over a 10. Again, if the PC's passive score isn't high enough, they will never, ever find the thing they're looking for. An automatic fail.

I hesitate to call it "Take 10" despite its similarities. It's just a way of adjudicating for the DM to get at a result he or she can narrate. For me, it goes like this: Is the player's action declaration an automatic success or failure? If yes, narrate a result. If no, then is the player's action declaration a task that is performed repeatedly? If yes, then passive check to resolve. If no, then ability check to resolve.

As above, I think it's fine for a PC's passive check to fail against a given DC. It's just up to the DM to set fair and consistent DCs given the action declaration the player makes. There's also a rule in the DMG for when player have their characters commit 10 times the normal amount of time on a given task in exchange for automatic success. So in general I'm inclined to just grant success for that investment of time resource, but in some cases, a passive check is warranted. The context will tell.

With a roll, the skilled Investigator will still usually be the one to find the info, likely in less time. There's sufficient niche protection. The fighter may fail bashing the door down on a roll (my players use crowbars to get Advantage), but if the wizard then comes up and does it, the fighter can claim to have loosen it for him. Niche protection can come from narrative and role-playing too. Plus, if something requires a particular skill to accomplish, the party will generally have the person with the best score attempt it, which also re-enforces niches.

Wait, what? Are you suggesting even things like bashing a door down, which is not a repetitive actions, be handled with passive checks? So the DM could just look at players stats and skills, set a DC, and know whether each character will succeed or fail at most tasks ahead of time? That's not action resolution, that's predetermination. Really, is that what you're suggesting?

No, I am just referencing an old D&D trope for effect - unlikely character A succeeding where likely character B failed, which parallels your example. Har har, everyone has a laugh. But I think ultimately it's at character B's expense, so I can do without it. I'll seek my humor elsewhere.

 

[jgsugden]

I look at it this way: There are three parts to a trap/danger: IDENTIFY IT, INVESTIGATE IT, DEFEAT IT. Basically, you need to realize it exists, then you need to figure out how to beat it, then you need to successfully perform those steps. Not all traps/dangers will involve difficulty in all three areas.

First, you need to identify a trap exists. Sometimes the traps are hidden. In these cases, you need perception to see the thing that looks out of place. However, some traps or dangers might be quite obviously out of place and will not require a perception check to notice that there is trouble afoot.

Once you realize there is something of concern, you need to figure out what to do about it. This is often an investigation check, but it could be arcana, nature, medicine, survival, or something else. The DM should ask the PC to make a check that makes sense for the trap and the skills of the PC. If this succeeds, they know what their options are regarding the trap / danger.

Once they know what to do, they need to do it. This may be easy (set fire to it), or it could be complex (sabotage the inner mechanism without disrupting the outer shell). This could be resolved through the PC describing their action, or it could require a sleight of hand check, a thieves tools check, an acrobatics check, a performance check, a stealth check, or whatever else makes sense to bypass or disable the trap.

I try to make sure my traps are varied so that some of them require only one roll (you can avoid it easily once noticed, it might be hard to actually disable an obvious and simple trap, etc...), some two (hard to spot, hard to figure out but trivial to disable; obvious to spot but a nightmare to figure out how to disable and then very technically challenging to disable; etc...), and some three. The more checks you need to make, the lower the average DC of those checks should be.

I've actually been using this idea for about 20 years, although how I implement it has changed with each edition. It really works.

 

[iserith]

I look at it this way: There are three parts to a trap/danger: IDENTIFY IT, INVESTIGATE IT, DEFEAT IT. Basically, you need to realize it exists, then you need to figure out how to beat it, then you need to successfully perform those steps. Not all traps/dangers will involve difficulty in all three areas.

First, you need to identify a trap exists. Sometimes the traps are hidden. In these cases, you need perception to see the thing that looks out of place. However, some traps or dangers might be quite obviously out of place and will not require a perception check to notice that there is trouble afoot.

Once you realize there is something of concern, you need to figure out what to do about it. This is often an investigation check, but it could be arcana, nature, medicine, survival, or something else. The DM should ask the PC to make a check that makes sense for the trap and the skills of the PC. If this succeeds, they know what their options are regarding the trap / danger.

Once they know what to do, they need to do it. This may be easy (set fire to it), or it could be complex (sabotage the inner mechanism without disrupting the outer shell). This could be resolved through the PC describing their action, or it could require a sleight of hand check, a thieves tools check, an acrobatics check, a performance check, a stealth check, or whatever else makes sense to bypass or disable the trap.

I try to make sure my traps are varied so that some of them require only one roll (you can avoid it easily once noticed, it might be hard to actually disable an obvious and simple trap, etc...), some two (hard to spot, hard to figure out but trivial to disable; obvious to spot but a nightmare to figure out how to disable and then very technically challenging to disable; etc...), and some three. The more checks you need to make, the lower the average DC of those checks should be.

I've actually been using this idea for about 20 years, although how I implement it has changed with each edition. It really works.

Overall, that sounds like a good way of thinking about it, but I am hesitant to require ability checks regardless of the player's action declaration as you seem to suggest here. My philosophy is that I can't determine uncertainty until a player has described what he or she wants to do.

 

[GreenTengu]

I don't think anyone can blame players for ignoring Investigation and the whole Intelligence attribute in general. It really is a pretty worthless attribute unless you are a Wizard or one of the wizard-y subclasses that uses it to determine your spell DCs. And even then, if you avoid spells that even have DCs then you don't actually need it at all.

I mean, really... you are going to demand that one player whose attacks and abilities don't in any other way interact with the Wisdom or Intelligence scores have to raise both of them in order to do the most basic effective thing... on top of naturally raising their Constitution so they can survive being hit since they are forced to be in melee and don't have ACs any higher than the Fighter, but do have lower HPs... and, naturally, it is expected their Charisma be high as well because they need to make those Bluff checks in addition to those Stealth checks in order to deal their extra damage in combat, which is the only way they are holding up their part of the game.

I mean, sure-- it is one thing to hopefully make it so that all attributes CAN be used resulting in different effects, but it is another expecting that one player's stats be 14+ across the board in order to functionally play their chosen roll.


The only way I can see it making sense for the whole "find the trap", "figure out the trap" and "disarm the trap" being entirely separate rolls is if you expect you are going to get more than one character involved in dealing with it. But traditionally this has all fallen onto the shoulders of a single character.

Although one of the nice things about 5th edition is that it doesn't even have to be a Rogue who handles all the traps. I could easily imagine a Dwarven Engineer or a Tinker Gnome of nearly any class being even better at taking apart traps and locks and the like than your average standard Thief. And, by all means, you can have those skills on those characters without them having to be Rogues.

 

[doctorbadwolf]

I use Perception to notice things, scan a room for anyting out of place, etc. You're just using your senses to gather data.

Investigate comes into play whenever examination is happening. You are using reasoning and knowledge to turn sensory data into useful information. Observation in the Holmesian sense. You are studying a thing. Also, I use Investigate as part of any research challenge.

For anything complex, you gotta use both. And probably some Knowledge skills.