D&D 5E Modeling Uncertainty

[ClearlyTough69]

In my next post, I'll test this out with a very diplomatic guard, and a very undiplomatic guard.

First, the diplomatic guard.

The guard is telling the truth, so it's a contest between the character's Insight and the guard's trustworthiness, represented as a -5 Diplomacy check (the inverse of his Diplomacy modifier).

The character's check result is 8 (natural 3, +5 Insight). As we've already established, the guard's check result is -5. On the face of it, the character detects that the guard is being truthful; her degree of success is 13 (8 - -5).

Assessment = d20 + degree of success OR - degree of failure
In this case = natural 4 +13 = 17.
This meets the threshold of 10, so the character makes an accurate assessment of the outcome of the check: she believes the guard is being truthful.

Confidence = d20 + degree of success/ failure
In this case = natural 12 +13 = 25.
This exceeds the threshold for absolute certainty, so the DM reports that the character is absolutely certain that the diplomatic guard is being truthful.
___________________

Now, the undiplomatic guard, whom nature has gifted with a shifty demeanour.

This guard is also telling the truth, but with a Charisma of 5, his trustworthiness can be represented as a +3 Diplomacy check (the inverse of his Diplomacy modifier).

The character's check result is still 8 (natural 3, +5 Insight). As we've already established, the guard's check result is 3. On the face of it, the character detects that the guard is being truthful; her degree of success is 5 (8 - 3).

Assessment = d20 + degree of success OR - degree of failure
In this case = natural 4 + 5 = 9.
This does not meet the threshold of 10, so the character makes an erroneous assessment of the outcome of the check: she believes the guard is lying. She has mistaken his unfortunate demeanour as a sign of untrustworthiness.

Confidence = d20 + degree of success/ failure
In this case = natural 12 + 5 = 17.
This exceeds the threshold for being very sure, so the DM reports that the character is very sure that the undiplomatic guard is lying, when in fact he's being entirely truthful.
_____________________

That seems about right to me. The character's low Insight roll and low assessment roll caused her to think that the shifty guard was lying, but she was mistaken; her comparatively high confidence roll caused her to be unduly confident in her assessment. Most of the time (ie with roughly average rolls) she would quite rightly be certain that the undiplomatic guard was telling the truth.

The mechanic does require that all rolls be made and analysed together before a player can learn what his character's perceptions of the situation are.

 

[ClearlyTough69]

Now, the undiplomatic guard, whom nature has gifted with a shifty demeanour.

[...removed for brevity...]

the DM reports that the character is very sure that the undiplomatic guard is lying, when in fact he's being entirely truthful.
_____________________

That seems about right to me. The character's low Insight roll and low assessment roll caused her to think that the shifty guard was lying, but she was mistaken; her comparatively high confidence roll caused her to be unduly confident in her assessment. Most of the time (ie with roughly average rolls) she would quite rightly be certain that the undiplomatic guard was telling the truth.

I hope this addresses your point, Lanefan:

More broadly, how does your idea allow for a false-positive result where the PC thinks the guard's lying when he isn't?

 

[ClearlyTough69]

I like the general tenor of the idea, but the particulars seem to be able to lead to some conditions that I don't understand at the assessment stage. My areas of confusion are marked with '(?)'. (Possibly I have just misunderstood; if so, apologies in advance.)

Here's the same situation, but with different dice rolls:

The guard is indeed lying, so it's a contest between the character's Insight and the guard's Deception.

The character's check result is 15 (natural 10, +5 Insight); the guard's check result is 14 (natural 14, 0 Deception modifier). On the face of it, the character detects that the guard is lying; her degree of success is 1 (15-14).

Assessment = d20 + degree of success OR - degree of failure
In this case = natural 4 +1 = 5.
This does not meet the threshold of 10, so the character makes an erroneous assessment of the outcome of the check: she (?) believes the guard is telling the truth even though she won the contest to 'detect' that he was lying (?).

You are right that the assessment can end up undoing the original check. And as you go on to point out, this seems to be an issue with skills that determine what a character perceives and believes about the world around them: skills that in themselves have no discernible impact in the world. The skills in question are Insight, Investigation and Perception, and the knowledge skills: Arcana, History, Medecine in some circumstances, Nature, and Religion.

For these skills, you could just ignore the assessment roll. However, you could still opt to use it if the skill check is unsuccessful, allowing a character to be misled or deluded to some degree. For example, a druid's Nature check indicates that she can't identify a fungus; if her assessment roll indicates an incorrect assessment, she might have the mistaken belief that she can identify it, but she's deluding herself. This allows her to (a) fail to identify a poisonous deathcap, and (b) mistake it for an edible field mushroom. That creates the opportunity for story telling mediated by the skill mechanics.

Whether or not you make the assessment roll for these skills, there's still a place for the confidence roll.

The assessment roll comes into its own when you try to affect the world, but it's not immediately apparent whether your attempt is successful. It allows for situations like:

• The rogue swears blind that she can't disarm the trap, but she's already done it
• The ranger has no idea where he's going, but in fact his intuition is taking him the right way anyway
• The paladin thinks he's persuaded the courtier to put in a good word to the duke, but actually the militia are on their way to arrest him
• The bard reckons his oration bombed, but he's won the respect of the high commander

 

[ClearlyTough69]

EDIT: Ok, after thinking about it a bit more, I think that the oddity is coming from the fact that the original task (lie detection) itself concerns belief. If the task were instead solving a puzzle, then things make more sense. One might

1. Solve the puzzle and believe that the solution is correct; or
2. Solve the puzzle and believe that the solution is incorrect (this case is still a little wonky); or
3. Not solve the puzzle and believe that it is not solved (no solution); or
4. Not solve the puzzle, but believe that you have solved it (incorrect solution).

Yes, I think your point about belief is right. I've written another reply about that.

Building on your example of the puzzle, here's the same thing for an attempt to disarm a trap:

• disarm the trap and believe you've disarmed it
• disarm the trap but not realise that you have
• fail to disarm the trap and realise you haven't
• fail to disarm the trap but believe you have disarmed it.

 

[Tony Vargas]

The guard isn't trying to deceive or persuade, so he's not truly contesting the character's Insight. Instead we need a measure of how generally trustworthy the guard seems. I think this can be represented by the inverse of his Diplomacy modifier. If he is highly Diplomatic, his modifier might be +5; the inverse is -5.

That makes sense, but it's an un-intuitive presentation. Wouldn't leaving the DC to the DM (based on the situation and whatever factors might apply), but adding together the Diplomacy bonus of the truth-teller and the Insight bonus of the listener to hit that DC, be mathematically similar?

 

[Guest 6801328]

CT,

I'm still mulling over your proposal. Three initial reactions:
1) It seems to achieve my design goal of making positive, negative, false positive, false negative, and "no idea" all possible, with varying degrees of probability (other than 100/50/0)
2) It feels like a lot of dice rolling and arithmetic.
3) It may be that to achieve point #1 you must have two additional dice rolls, besides the player's roll. Not sure, but I think that may be the case.

 

[Lanefan]

I hope this addresses your point, Lanefan:

Yep, that seems to work.

 

[Lanefan]

1) It seems to achieve my design goal of making positive, negative, false positive, false negative, and "no idea" all possible, with varying degrees of probability (other than 100/50/0)

Mechanically, yes; though in the end it still comes down to DM narration as to how it goes over at the table. I like it, though: it's a big improvement on what the RAW give you to work with.

2) It feels like a lot of dice rolling and arithmetic.

At first glance I thought this too, but then realized that just like all the other fiddly systems the game has had over the years it'll only seem that way until you've done it a few dozen times, after which it'll become second nature.

Lanefan

 

[Hjorimir]

Disclaimer: I didn't read the entire thread (pressed for time right now).

Questing Beast has a video that touches on this. Basic idea, have the player roll 3 times and you randomly determine which of the 3 results you'll use as the DM. So if they player rolls well 2 out of the 3 times, they have a hunch that they probably succeeded. If they roll poorly 2 out of 3 times, they have doubts. Not a perfect solution, but it has potential.

 

[Guest 6801328]

Disclaimer: I didn't read the entire thread (pressed for time right now).

Questing Beast has a video that touches on this. Basic idea, have the player roll 3 times and you randomly determine which of the 3 results you'll use as the DM. So if they player rolls well 2 out of the 3 times, they have a hunch that they probably succeeded. If they roll poorly 2 out of 3 times, they have doubts. Not a perfect solution, but it has potential.

Oh, that's awesome! What you want (for ease of use) are three differently colored dice, and the DM has a special D6 with two sides of each color.

Wow.

I think I like this much better than my own idea.

There are some options (I'll have to ponder on this) to use the other two dice to mean something, so that you can differentiate between correct answers, wrong answers, and no answers. For example (this is really off the top of my head so the math is probably bad) if two of the three dice are successful but you get the unsuccessful die, the DM will tell you that you failed. But if two of the three are unsuccessful and you get one of them then the DM will give you the wrong answer. Maybe combined with hidden DCs?