D&D 5E Passive Investigation?

[Tony Vargas]

It's less about adhering to jargon than not confusing the listeners many of whom are already confused about what "passive" actually means in reference to a passive check.

Is think stating it a different way that contrasts intuitively might help. ::shrug::

: A passive check resolves uncertainty the same as an ability check. A task (approach to a goal) is determined to be uncertain, a DC is determined, and if the task is being performed repeatedly, a passive check is used to resolve it.

That doesn't really sound like uncertainty, since it gives a fixed result. At most, it's the DM making his ruling 'blind' (without knowing the abilities in question). Once the situation actually comes up, that information is readily available.

I would say an example of passive Investigation coming into play might be as an activity while delving, say, a ruin of an ancient empire.

Investigation, maybe, or some other int check perhaps.

Due to the esoteric nature of the hieroglyphs, the less than ideal conditions in the dungeon, and places where the runes were defaced by monsters or faded with time, a standard investigation uncertain.

Uncertain for whom, though, would seem to be part off the process.

Where did this repeated activity stuff come from? Sounds like 3.x 'take 20.

 

[iserith]

Is think stating it a different way that contrasts intuitively might help. ::shrug::

Some kind of thread on passive checks comes up on the regular around here and, I imagine, in other venues. And inevitably one or more people intuits it to mean that the character is being passive and that in other cases they are being active and that there are passive and active checks to distinguish the two. That's just wrong from a rules standpoint. So calling it an "active Perception check" does not help in my view. Leave it to a game designer to either run or explain their games poorly!

That doesn't really sound like uncertainty, since it gives a fixed result. At most, it's the DM making his ruling 'blind' (without knowing the abilities in question). Once the situation actually comes up, that information is readily available.

Again, we've had this discussion before, you and me. As I see it, the result doesn't come until well after uncertainty as to the task's outcome is determined with the step in between being the resolving of that uncertainty via a passive check or ability check against a DC (which itself might be fixed or variable). This also addresses certain objections to Expertise as I show in a recent thread on that subject.

Investigation, maybe, or some other int check perhaps.

I typically call for just the ability and the players apply the proficiency that fits their approach. The rules say the players might ask which applies, but I think it's better to reduce the amount of questions in the game.

Uncertain for whom, though, would seem to be part off the process.

In some cases maybe. But I think how the character impacts the outcome usually happens after uncertainty as to the outcome of the task is determined and their ability checks come into play.

Where did this repeated activity stuff come from? Sounds like 3.x 'take 20.

From the rules for passive checks.

 

[iserith]

Regarding "take 20," here are the rules for that from the d20srd:

Checks Without Rolls
A skill check represents an attempt to accomplish some goal, usually while under some sort of time pressure or distraction. Sometimes, though, a character can use a skill under more favorable conditions and eliminate the luck factor.

Taking 10
When your character is not being threatened or distracted, you may choose to take 10. Instead of rolling 1d20 for the skill check, calculate your result as if you had rolled a 10. For many routine tasks, taking 10 makes them automatically successful. Distractions or threats (such as combat) make it impossible for a character to take 10. In most cases, taking 10 is purely a safety measure —you know (or expect) that an average roll will succeed but fear that a poor roll might fail, so you elect to settle for the average roll (a 10). Taking 10 is especially useful in situations where a particularly high roll wouldn’t help.

Taking 20
When you have plenty of time (generally 2 minutes for a skill that can normally be checked in 1 round, one full-round action, or one standard action), you are faced with no threats or distractions, and the skill being attempted carries no penalties for failure, you can take 20. In other words, eventually you will get a 20 on 1d20 if you roll enough times. Instead of rolling 1d20 for the skill check, just calculate your result as if you had rolled a 20.

Taking 20 means you are trying until you get it right, and it assumes that you fail many times before succeeding. Taking 20 takes twenty times as long as making a single check would take.

Since taking 20 assumes that the character will fail many times before succeeding, if you did attempt to take 20 on a skill that carries penalties for failure, your character would automatically incur those penalties before he or she could complete the task. Common “take 20” skills include Escape Artist, Open Lock, and Search.

Ability Checks and Caster Level Checks
The normal take 10 and take 20 rules apply for ability checks. Neither rule applies to caster level checks.

So I don't think passive checks in D&D 5e are exactly analogous to the above chiefly I think because you seem to go straight to process in 3e instead of the DM thinking whether mechanics are needed at all to resolve the task.

There is a rule in the DMG on multiple ability checks, however, that says if you spend 10x the amount of time on a task as you normally might, you automatically succeed. For certain tasks, and not others, at the DM's discretion. An impossible task is still impossible no matter how much the character tries, for example. The writing in this section is particularly bad in my view at a certain point because it seems to muddle checks and tasks which is deeply annoying to me.

 

[Tony Vargas]

From the rules for passive checks.

Looks like an example rather than a dividing line.

I'd caution folks not to parse rules too closely, but to read for general understanding. It's English, not algorithms.

But, to be clear, my opinions about the viability of the extremes of contested checks and passive checks vs fixed DCs is just about the probabilities involved and the impact on play, not an interpretation of the rules meant to establish an unambiguous reading of them.

 

[iserith]

Looks like an example rather than a dividing line.

I'd caution folks not to parse rules too closely, but to read for general understanding. It's English, not algorithms.

But, to be clear, my opinions about the viability of the extremes of contested checks and passive checks vs fixed DCs is just about the probabilities involved and the impact on play, not an interpretation of the rules meant to establish an unambiguous reading of them.

I would say the bit about "secretly determining whether the character succeed at something without rolling dice" bit was addressed pretty well by [MENTION=6701872]AaronOfBarbaria[/MENTION] upthread. That just leaves the tasks-done-repeatedly application which works in play in my experience.

 

[Ganymede81]

I've been letting my players use their passive skill checks as a sort of ersatz Take 10 in low-pressure situations. That's one way to incorporate the bonus from Observant.

 

[quandaratic]

I’m going to offer this as a case for using the mechanic: When a player makes an Ability Check, their Passive Score for the same Skill functions as the lowest possible result for that check.
I was dubious about it, at first, but I’m going to try it in my games.

Disclaimer: none of this is intended as “this is right, and your fun is wrong.” Nor is it intended as “Jeremy Crawford said it, so it has to be correct; all hail the Crawford.” I’m just really interested in finding the maximally valid and consistent model for roleplaying a real person, then deciding what approaches are most conducive to a fun game. …which is why I spend way too much time scrutinizing the core books.
Most of it has also been stated, in various ways, over the course of this thread, but this is intended to be comprehensive.

Here’s how I think this proposition works: 1) there are 3 different mechanics for Passive Checks, which are supported by the core books, and 2) they provide mechanical support for the concept that a highly-skilled character should be able to regularly achieve success at easy tasks, in easy conditions, when a Skill makes sense in a passive sense. 3) If that 2nd premise is accepted, then a highly-skilled character should also be able to succeed at easy tasks, in easy conditions, for all Skills, which would be presented by a Passive Score functioning as a minimum value for an Ability Check.
…and this is honestly just the same thing as a DM deciding to fudge a Player’s bad die roll, and let them have the success, but this adds a consistent mechanic to it.

Mechanic 1:
A Passive Check can be made, where the single Passive Score opposes the DC of a check, instead of the results of die rolls for many Skill Checks.
— Is it in the books: Yes; it’s the 1st definition of Passive Checks, in the Players Handbook.
— Is it valid:
— It assumes a statistical average — that a Character whose Passive Score is 10 would yield an average result of 10, on many Ability Checks, given a sufficient number of attempts. Here, there’s a possible invalidity, in sample size — if it’s used to represent a fairly small number of individual Ability Checks, the die rolls of those individual checks could easily yield a very different single result, from their average.
— It assumes that the narrative resolutions for each individual Ability Check, represented by the single Passive Check, should be as similar as possible. Otherwise, it suffers the flaw, of not indicating which individual Ability Checks would have been passed and which would have been failed.
— Is there a use case: Yes, for any skill that is repeated many times, but the above assumptions limit proper usage. The similarity-of-individual-checks flaw would make a difference in the case of detecting traps and secret doors in a dungeon; the 2nd type of Passive Check is better in this case. A case like researching all day, in a library is more of a case for this check, because it’s more feasible for the character to be taking notes, and keeping relevant books near them, and discover the same insight at any point in the 360 Ability Checks over an hour of game time, such that the narrative resolutions would be the same.

Mechanic 2:
A Passive Check can be made, where the single Passive Score opposes the DC of a check, instead of the Player making an Ability Check.
— Is it in the books: Yes; it’s the 2nd definition of Passive Checks, in the Players Handbook.
— Is it valid:
— It assumes that the Character has no knowledge of the circumstances which initiate the check.
— It assumes a level of ability in a Skill, which the Character can maintain, without having to devote particular attention to that Skill.
— It assumes that the Character can devote some attention to that Skill, because the Character is not focusing on doing something else.
— Is there a use case: Yes, when the Character doesn’t know what narrative element is causing the check. The detect-a-trap-in-a-dungeon would be a good case for this check; if the 1st mechanic is used to represent the check, it would suffer at least 1 invalidity.

Mechanic 3:
A Passive Check can be made, where the single Passive Score opposes the result of the DM’s die roll, for a monster/NPC/creature who is making an Ability Check.
— Is it in the books: Yes, though there’s arguably a contradiction.
— The Players Handbook definition specifies “no dice are rolled” and “without rolling dice,” which would indicate that this type of check does not exist.
— However, it then provides an example of a Character noticing a hidden monster, and the DM would have rolled a Stealth Check for the monster to be hidden.
— The Players Handbook goes on specify, in the rules for hiding, in Combat, that a Dexterity(Stealth) Check opposes Passive Perception, and D&D is a game where the DM uses the same mechanics for monsters/creatures/NPCs, which the Players use for their Characters.
— The DM Guide specifies that, in non-Combat and Combat situations, for creatures which seek to perform a task which would be opposed by a PC, the DM may roll the creature’s Ability Check against the PCs Passive Score, if the Player has no knowledge of the creature or their intention.
— Why would both books establish uses of this mechanic, when the Players Handbook says that no die is rolled? Possibly because the Players Handbook is for Players, who truly don’t roll any dice in a Passive Check.
— Is it valid: the assumptions are the same as Mechanic 2

Premise:
Passive Checks can be made for any skill, not just for Perception.
— Is it in the books: Yes; this is indicated by the language used, in the definition of Passive Checks, which is not specific to Perception, and by specific mention of other Passive Checks, especially Passive Intelligence(Investigation), in both the Players Handbook and the DM Guide.
— Is it valid:
— Sometimes, depending on the particular Skill or Ability being checked. It assumes that the particular Ability or Skill being checked, would actually make sense, in a passive sense. Eg., a Character probably can’t climb a rope without devoting their attention to that task; this would be a case for Passive Athletics, but doesn’t really made sense.
— Is there a use case:
— In the 1st mechanic, yes.
— For the 2nd and 3rd mechanics, also yes. The case of Passive Intelligence (Investigation) is documented, but it makes sense that any Skill or Ability that can have a passive function could be used in the same way. I think there are strong cases for Insight and Survival, and for general WIS, INT, CHA, and CON checks.

Conclusion:
Separately, each mechanic for Passive Checks has flaws. Together, though, they allow Characters to succeed at easy (sometimes moderate) tasks, without rolling a die, which eliminates the possibility of failures due to a bad roll. If these checks applied all the time, then the resulting auto-successes would be invalid. However, the Passive Check mechanics have sufficient limitations to their application, that they would only be used when the narrative supports an easy win for the Character.
So, a Passive Check should be used:
- only when it’s the right type of Passive Check.
- only when the Character isn’t focused on a different activity.
- only when the Character’s ability to perform that skill isn’t being limited by a Condition.
- only when the Skill makes sense in a passive sense (for the 2nd and 3rd mechanics).
- only when the narrative resolutions should be the same for each Ability Check represented (for the 1st mechanic).

…basically, in conditions which are sensical and favorable. In those constraints, the numbers play out as auto-successes for Easy DC Challenges, and only sometimes for Moderate DC Challenges. It would take a Character with Ability Modifier and Proficiency Bonuses of +3 and +2, to auto-succeed a Moderate Challenge. So, we’re talking about Characters with very high Ability Scores (or good Ability Scores at higher level), who are proficient at the Skill which is being checked. Average would not auto-succeed a Moderate Challenge, without Advantage, and a Character with no Proficiency Bonus and a negative Ability Modifier would even auto-fail Easy Challenges. With Disadvantage, many Characters with multiple bonuses to the check would fail the same Easy Challenge. Narratively, it still takes special skill to do special things, and reliably avoid botching those efforts.


…then, the next step.
Premise:
Used together, and in appropriate narrative situations, Passive Checks provide a valid framework to represent the concept, that a highly-skilled Character should be able to regularly succeed at easy tasks, even if their Player rolls really low results on their rolls.

Premise:
A highly-skilled Character should be more able to achieve regular success at easy tasks, when they are focusing at their task, than when they are not focusing on their task.

Conclusion:
When a Player makes an Ability Check, the Character’s Passive Score for that Ability or Skill may be used as a minimum value for that Ability Check.
Is it in the books: No, not that I can find.
Is it valid: If the 1st premise is valid, it seems so. There is a weak point for the 3rd mechanic, and any DM would be justified in rejecting this concept because of the Player’s Handbook plainly stating “no die is rolled.” However, that contradiction works against both proving and disproving this thesis, since it has to be ignored, either way.

Whether or not this whole thing is valid really rests on a single subjectivity for the DM:
Do you believe that a Character, who is supposed to be an expert in a particular skill, should be able to auto-succeed an easy check, in that skill, if they have plenty of time, are not being distracted by some other task, and are not suffering some condition which limits their ability?
Should the wizard, of able mind, taking a few minutes to survey their surroundings, be able to pass an Intelligence Check, to deduce a crucial insight, even if their Player rolls a 2? A 5th-level wizard with an Intelligence score of 19 would still fail a DC 10 check, after adding the ability modifier of +4, and proficiency bonus of +3, which means that the brains of the group just couldn’t think of the easy answer, for no narrative reason.
It is totally acceptable, if the answer is “no, this concept is neither valid nor conducive to my gameplay.” This is just a proposition.
I’m going to try out this mechanic, just for the idea of letting smart Characters be smart, strong Character be strong, and heroes be heroes.

 

[iserith]

Whether or not this whole thing is valid really rests on a single subjectivity for the DM:
Do you believe that a Character, who is supposed to be an expert in a particular skill, should be able to auto-succeed an easy check, in that skill, if they have plenty of time, are not being distracted by some other task, and are not suffering some condition which limits their ability?

There is no check, passive or otherwise, if a DM believes this. The character just succeeds.

Should the wizard, of able mind, taking a few minutes to survey their surroundings, be able to pass an Intelligence Check, to deduce a crucial insight, even if their Player rolls a 2? A 5th-level wizard with an Intelligence score of 19 would still fail a DC 10 check, after adding the ability modifier of +4, and proficiency bonus of +3, which means that the brains of the group just couldn’t think of the easy answer, for no narrative reason.

The question you ask here suggests that you're not taking the DM's consideration of uncertainty into the equation. If there's no uncertainty as to the outcome for whatever reason and there's no meaningful consequence of failure, then there's no check.

I'm led to believe you're going to check before passing it through the judgment of the DM, especially as you remark "…and this is honestly just the same thing as a DM deciding to fudge a Player’s bad die roll, and let them have the success, but this adds a consistent mechanic to it." That DM should not have called for a check in the first place because if the character cannot fail, there is no uncertainty.

This is the adjudication process:

1. The DM describes the environment.
2. The players describe what they want to do.
3. The DM decides if the outcome of what the players describe is certain or uncertain and whether the task has a meaningful consequence of failure. Only if it's both uncertain and has a meaningful consequence of failure does the DM call for an ability check (or a passive check).
4. The DM narrates the results of the adventurers' actions.

The DM's judgment in #3 is the "consistent mechanic" that you're looking for and it's already in the rules. By all means try out the house rule you propose. I would just say it's not solving a problem in the rules, but rather a problem with the way the DM adjudicates.

 

[jgsugden]

I keep coming back to a general rule: If you can use a skill without taking an action (perception, intelligence skills, investigate, charisma skills), treat it as passive and use a result of 10 + skill (+/- 5 for advantage/disadvantage). If you take a moment (aka an action) to use the skill, you get to improve upon the passive score by rolling for the skill check and treating the passive result as a floor.

Intelligence skills - you know what you know, but if you take a moment to think you might remember something additional.

Charisma skills - you have your natural charisma, but if you take the extra time to flirt/intimidate/etc... you can be more effective.

Perception - You see most things, but have to focus a bit to see more.

Investigate - You get how many things work with a glance, but if you stop to assess it you can figure out even more.

 

[quandaratic]

[MENTION=97077]iserith[/MENTION] I agree, and I think we're describing the same thing, but I would concede that my use of the term 'auto-succeed' is misleading.
A DM's uncertainty, especially when no die is rolled, is really just the difference between a DM needing to look at the numbers, and a DM just knowing that the particular Character would succeed at the particular Check of the particular Skill.
Personally, I would probably be checking number a lot, just because I'm super ADD. Other DMs wouldn't need to, if they have less squirrelly brains than I do.