D&D 5E Quick Question on AC and Proficiency bonus

[Ruin Explorer]

Thank you for playing the voice of reason. Your interpretation is consistent with my own reading of the rules.

The other interpretations just seem so wacky.

I will say that problem Tony describes can be a real issue (where a real expert misses a "hard" roll an a totally untrained 0 stat bonus person makes it) for verisimilitude, especially if it keeps happening, but it has been in every edition to some extent, where people can roll on the same things, and 5E cunningly laterally works around it with "Working Together", so that two or more PCs can work on something, and instead of the one with the low bonus just rolling high, the one with the high bonus can roll with Advantage.

This produces much more aesthetically pleasing results and feels more D&D-ish, as a bonus.

As an aside, until I was a player in 5E, I didn't realize how clever "Working Together" was as a way of solving this. As a DM I'd been letting people roll separately or "Work Together", but they usually rolled separately and it often had un-aesthetic results (or ones that lacked verisimilitude, rather). Having played 5E a lot more now as DM I'm now suggesting people use "Working Together" whenever I see the possibility for a dodgy-looking result, and the players seem to be totally into it. Everyone loves Advantage.

 

[The Crimson Binome]

I'm pretty sure that at some point in the DMG it literally says not to roll on stuff that isn't dramatic and where failure is unlikely.

"Dramatic" has nothing to do with it, because that's a meaningless term. It belongs to an entirely different category of game. I think what you're thinking of is that the outcome has to "matter"; which is a slightly less-meaningless term.

That advice specifically exists in order to bypass the physical act of rolling dice repeatedly until the inevitable success occurs. If nothing bad happens when you fail, and there's plenty of time to keep trying, then we can just skip ahead to the success. Another way of looking at it is that, over time, the chance of success approaches certainty (and thus there's no need to roll, because the outcome is effectively certain).

But for a one-shot attempt where you couldn't feasibly try again? You'd better roll, if there's any chance of failure. Otherwise, you've replaced the basic determination engine with pure DM fiat, and that's not a game.

 

[Ruin Explorer]

Otherwise, you've replaced the basic determination engine with pure DM fiat, and that's not a game.

No.

This is factually wrong.

Unless you replace all rolls with "pure DM fiat", it is still "a game" (arguably even if you did, but that's another thread). Replacing one roll here or there, or not making them, has absolutely no impact on whether it is "a game". None whatsoever. These are RPGs - roleplaying games. DM fiat - or player fiat in some RPGs which don't have DMs - is always going to be a part of them.

D&D isn't a video game. There are times you don't roll the dice, and if you think it's always mandatory to roll a DC13 check when the player has +11 (or +12, even), well, that puts out in a pretty weird land, I'd suggest. Obviously you're welcome to occupy that land, inhabited by DMs who call for a Perception check to notice something that's sitting on a table right in front of the PCs with a big sign saying "NOTICE ME" on it. But it's a wacky place, and it's not RAW/RAI.

 

[Charlaquin]

The other interpretations just seem so wacky.

I will say that problem Tony describes can be a real issue (where a real expert misses a "hard" roll an a totally untrained 0 stat bonus person makes it) for verisimilitude,

Only if you use the old “one check represents your best attempt” rule, instead of simply allowing the expert to try as many times as he is willing to risk the consequences of failure.

 

[Charlaquin]

That advice specifically exists in order to bypass the physical act of rolling dice repeatedly until the inevitable success occurs. If nothing bad happens when you fail, and there's plenty of time to keep trying, then we can just skip ahead to the success. Another way of looking at it is that, over time, the chance of success approaches certainty (and thus there's no need to roll, because the outcome is effectively certain).

But for a one-shot attempt where you couldn't feasibly try again? You'd better roll, if there's any chance of failure. Otherwise, you've replaced the basic determination engine with pure DM fiat, and that's not a game.

On this I agree with you.

 

[Ruin Explorer]

Only if you use the old “one check represents your best attempt” rule, instead of simply allowing the expert to try as many times as he is willing to risk the consequences of failure.

Yeah, but if the expert can re-roll, so can the idiot. That's the problem. And with the small bonuses, you can get a scenario where both roll like three times and the idiot gets it and that's even uglier than that "one roll = best attempt" scenario! Usually this is an issue with History or Arcana or the like, and cooperative players who are good roleplayers can help deal with it, but some players are just flummoxed by it, in my experience.

Again, Working Together largely eliminates this as an issue in actual play so long as you use it.

 

[Charlaquin]

Yeah, but if the expert can re-roll, so can the idiot. That's the problem. And with the small bonuses, you can get a scenario where both roll like three times and the idiot gets it and that's even uglier than that "one roll = best attempt" scenario!

If you are adhering to the rule that an action must have a cost or consequence for failure for a roll to be called for to resolve it, then having the unskilled character attempt it at all is a very risky move.

Usually this is an issue with History or Arcana or the like, and cooperative players who are good roleplayers can help deal with it, but some players are just flummoxed by it, in my experience.

I’m not sure what task you’re saying is being resolved by the History or Arcana roll where this would be a problem.

Again, Working Together largely eliminates this as an issue in actual play so long as you use it.

Working together is a very good rule, I do agree with that.

 

[Salthorae]

That's kind of completely not how D&D works, though. Like, you're welcome to run it that way, and I'm sympathetic to running it that way, but that is absolutely not RAW or RAI. Particularly not the different DCs. DCs, in D&D, are not set "to the character". That would make for a completely different, wildly different system.

So basically you're literally ignoring the rules, and using DM fiat to plaster a pretty obviously wonky issue that is the direct result of using a d20 for these rolls, combined with having a relatively small bonus to the roll (even for the "master"). Again, I'm sympathetic to that, but claiming that somehow "proves Saelorn wrong" is absolute and total arrant nonsense.

Yes, if you ignore the rules, and use DM fiat, you can fix almost any issue with any system. But that's what you're going to have to do.

The reality is that isn't much of an issue in an actual play, though, simply because in 5E (and indeed most versions of D&D except 3.XE/PF), this scenario just doesn't come up very much. 5E particularly makes it very unlikely due to the "Working Together" rules, which means the master almost certainly has someone else in the party helping him, which means he's making the check with Advantage.

But please don't tell people the system isn't wonky here. This is a specific issue with all systems that use a d20 and a small bonus as the main roll.



Whilst they're obviously papering over a hole and claiming there is no hole, which is ludicrous, it's not true to say anything with 20 points warrants a check. I mean, you can run it that way, but that's also not really RAW or RAI - though less severely, because you're not making up rules, you're just overusing them.

The moderating factor is generally if something is fairly easy, you shouldn't require a check, even if it theoretically has a DC of 5 or 10 or whatever.

In reality, because of the way 5E works, and the Working Together rules, this is rarely an issue - but it's certainly an underlying flaw, and ignoring it or pretending it's not a flaw is pretty bloody silly. It's something that becomes obvious as a flaw the moment the players forget the Working Together rules and start making separate checks on something like Arcana - because of the high variance and low bonus, especially at lower levels, you'll frequently have a character who it seems it is um... unlikely... would know that who actually makes the check. The difference between 10 INT, no skill, and 16 INT, skill is only +5, so the odds of the other guy knowing rather than the wizard are actually pretty good. If D&D used 3d6 or something it'd be a completely different story, of course. But it doesn't. Which is cool. But we can't pretend the issue isn't there - it's just rarely a big deal.

Sigh... I make one off the cuff statement and you respond with a whole essay. I didn't say I did the multiple DC's in my games, I was just throwing something out there, and I made no claims to "proving @Saelorn wrong".

As to the other part, the DMG literally says that a DM decides if a roll is necessary.

When a player wants to do something, it’s often appropriate to let the attempt succeed without a roll or a reference to the character’s ability scores.
...
Only call for a roll if there is a meaningful consequence for failure.

When deciding whether to use a roll, ask yourself two questions:

• Is a task so easy and so free of conflict and stress that there should be no chance of failure?
• Is a task so inappropriate or impossible — such as hitting the moon with an arrow — that it can’t work?

The DMG also says that a DM gets to determine the DC's or even change ones in published adventures.

It’s your job to establish the Difficulty Class for an ability check or a saving throw when a rule or an adventure doesn’t give you one. Sometimes you’ll even want to change such established DCs. When you do so, think of how difficult a task is and then pick the associated DC from the Typical DCs table.
...
If you’ve decided that an ability check is called for, then most likely the task at hand isn’t a very easy one. Most people can accomplish a DC 5 task with little chance of failure. Unless circumstances are unusual, let characters succeed at such a task without making a check.

Going back to the master wizard/novice example, if it is something that the novice can do with relative ease, then the DC should be no higher than 10, we can agree on that right?

Let's call our "master wizard" 9th level, so +4 Proficiency bonus and +4 Int on their check. They're only failing that roll on a 1.

Going back then to the DMG guidelines, unless they happened to find themselves in a stressful environment, I wouldn't even make a "master wizard" roll, but I would call for a novice to make that roll in any situation. If they were in the middle of a battle, sure maybe have the master still roll for it, but barring that, why bother with a roll unless it has a consequence on failure.

Even if you assume a Moderate DC 15 that a novice can make but only half the time, unless there is a "meaningful" consequence for failure, the DMG literally says to not bother asking for a roll.

Obviously if you as a DM deem that there is meaningful consequence for failure (whatever that may mean to you as the DM) AND the task is in fact achievable by the PC (i.e. obviously impossible or DC > 20+PC modifiers), go ahead and ask for a roll. Otherwise the DMG advice is to not bother.

Also - If you really don't like the concept of a door failing to get smashed open by a musclebound barbarian because of a poor roll, but the wimpy rogue comes and busts it open with a natural 20, there is always the DMG variant rule that says if your Ability Score -5 is equal to or greater to the DC, it's an autosuccess.

 

[Tony Vargas]

Not so. Target numbers are fixed in 5e.

That's meaningless.

Once you compare DC and bonus, there's a natural roll that's success. It can end up being the same across a range of levels, whether you're scaling at 1/5, 1/2, of 1/1.

And that’s a problem?

It's a comparison.

 

[Tony Vargas]

Bounded accuracy was conceived very specifically as a response to the “treadmill effect.

Well, a reaction, anyway.

Since this thread started about AC it might be interesting to think about where BA has an impact relative to past editions. In the olden days through 3e, classes scaled different things differently. Fighters were a little better at fighting, and got a LOT better at very high level, in 3e that held for all sorts so skill specialties, due to cross-class skills, as well - in contrast spells got better with spell level, not even considering scaling, higher level spells just did more, more significant things.
5e, everything scales, if it scales at all, at the same much slower rate. There isn't much of a difference among characters when it comes to d20-resolved abilities.
But there are still 9 levels of spells.

. Anyone being able to attempt anything (within reason) is a consequence of bounded accuracy, but it is not its guiding principle, nor the reason for its inception.

It's a major benefit: it's possible to keep the whole party relevant in any set of skill-related tasks.
Even if it was an accident, they should take the win.

Bounded accuracy is a very popular feature of 5e, and one of its key selling points.

Its oft-cited as a great innovation of 5e.
But, then, it's also about the only innovation of 5e.

Just because you sometimes pit PCs against threats significantly above or below their level doesn’t mean the treadmill effect isn’t a problem.

The treadmill effect isn't a problem, per se. It's just a possibility when you use a randomizer with a linear distribution, and have leveling.

It's an apt metaphor for consistent scaling in such an instance, though.

As a result of the treadmill, threats significantly below the level of the PCs cease to be actual threats past a certain point,

That's not a consequence of a "treadmill," simply of rapid scaling. 1e certainly didn't have a treadmill effect - scaling was too inconsistent - but inferior foes rapidly ceased to be actual threats.