Common issues with DC based skill systems

[Zuras]

Huh. I like skills and DCs that far exceed the die range, but, from a Simulationist perspective, I can see how what you said makes sense. To put it in 3e parlance, I took the feat that lets me use the Computer skill to easily write code others can't; some people took the Layout feat to let them use the Computer skill to easily create good interfaces that others can't; yet other people the Hardware feat to let them use the Computer skill to easily fix physical problems others can't.

I guess there's more than one way to gatekeep, and to identify your specialists.

For things like the cure the space virus example, you can also turn it into multiple rolls, either requiring multiple successes or letting successes accomplish “damage” against the challenge.

If it’s going to take a bunch of play time, you can also split it up into a multi-part problem. Everyone at the table knows only Doctor Impossible can synthesize a cure, but the Doctor still needs the rest of the team out in the field gathering data to properly diagnose the cause making a bunch of perception and investigation checks.

[King of Nowhere]

If it’s going to take a bunch of play time, you can also split it up into a multi-part problem. Everyone at the table knows only Doctor Impossible can synthesize a cure, but the Doctor still needs the rest of the team out in the field gathering data to properly diagnose the cause making a bunch of perception and investigation checks.

Yes, this is how i try to handle things to give non-specialists some way to contribute. Find something that's within their field of expertise that they can do to help

[Quertus]

“I wipe the brow of Doctor Impossible.”
— ancient gamer saying, meaning “I have nothing to contribute to this scenario.”

[Vahnavoi]

Most discussion on skill gaps is overly focused on rare events.

If you have simple bounded system where upper limit on a single check is 90% and the lower bound is 10%, you get a situation where the expert fails and the non-expert 1% of the time. Add in a hitpoint-like mechanic that allows the expert to fail more often than the non-expert, and the non-experts chance to succeed will asymptotically approach zero in comparison.

[Zuras]

“I wipe the brow of Doctor Impossible.”
— ancient gamer saying, meaning “I have nothing to contribute to this scenario.”

In actual play, Doctor Impossible mostly used his amazing science powers to enhance the psychic abilities of Captain Improbable so he could reverse the polarity of negative space wedgies. Granted that was because we were playing FATE, which makes it simple and natural to help each other out using the “create an advantage” action, rather than a d20 DC based system.

[King of Nowhere]

every time someone mentions a way their table cleverly interpreted/twisted a game mechanic to adapt it better to the circumstance, it reinforces my argument that it doesn't really matter which mechanic you use; it's how you use it that makes a difference

[Zuras]

every time someone mentions a way their table cleverly interpreted/twisted a game mechanic to adapt it better to the circumstance, it reinforces my argument that it doesn't really matter which mechanic you use; it's how you use it that makes a difference

That’s true for the core mechanics—you can get reasonable results from d20 roll-over, d20 roll-under, d100, 2d6, 3d6, and so on. The system itself does need to have a solid baseline of examples and techniques set out for determining consequences and resolving situations where a single pass-fail check is inappropriate.

The key is the GM needs to be experienced with multiple systems to have the needed tools. D&D 5e gives you a lot more latitude to resolve skill checks than it gives you tools to exercise that latitude with. Granted, lots of 5e-only DMs have actually been exposed to many different techniques, because tons of adventures use tracked successes/failures, effort accumulation, explicit permissions for who can attempt checks, and many other ideas from other games, since the typical adventure writer has played multiple other systems.

Most systems do a good-enough job if you play them as intended, but most simply don’t have rules, even modular ones, to support specific genres of play. If you really want to track encumbrance in 5e, for example, you’re better off importing rules from an OSR system that cares about it. Similarly, if you’re running an Intrigue campaign, you’ll need to find a third party supplement or steal rules from an espionage game for detailed rules on detecting characters’ accents and making good forgeries of official documents.

[King of Nowhere]

you’ll need to find a third party supplement or steal rules from an espionage game...

...or even homebrew them yourself.
yeah, the key thing is, when the system you are using does not handle well the thing you are trying to do, apply creativity

[Quertus]

In actual play, Doctor Impossible mostly used his amazing science powers to enhance the psychic abilities of Captain Improbable so he could reverse the polarity of negative space wedgies. Granted that was because we were playing FATE, which makes it simple and natural to help each other out using the “create an advantage” action, rather than a d20 DC based system.

I kinda figured wiping Doctor Impossible’s brow was an aid another / Create an advantage Action…

[Zuras]

I kinda figured wiping Doctor Impossible’s brow was an aid another / Create an advantage Action…

True, but brow-wiping is far more important in sympathetic magic systems than sci-fi, generally. An unintended drop of sweat in a potion you’re making or on the chalk circle you drew to keep a summoned spirit contained is far more likely to kill you. Still, it’s not nothing to say you wiped the brow of Doctor Impossible during the battle of the Tannhäuser Gate.

[King of Nowhere]

An unintended drop of sweat in a potion you’re making or on the chalk circle you drew to keep a summoned spirit contained is far more likely to kill you.

A drop of sweat into a cellular colture can ruin the production of a whole batch of life-saving drugs, potentially killing more people than the summoned spirit - if we didn't have precautions for that.
The escaping spirit makes for a better story, though.
I now wonder if wizards should operate in a clean room, wearing full environmental suits

[OldTrees1]

I now wonder if wizards should operate in a clean room, wearing full environmental suits

Naw. Full environmental suits contain too many strange materials. Any one of them might have a strange interaction with the magical experiment. It is better to stick to the traditional robes that have known interactions.
- Wizard that doesn't like how hot the env suits would get.

[Zuras]

A drop of sweat into a cellular colture can ruin the production of a whole batch of life-saving drugs, potentially killing more people than the summoned spirit - if we didn't have precautions for that.
The escaping spirit makes for a better story, though.
I now wonder if wizards should operate in a clean room, wearing full environmental suits

In Randall Garrett’s Lord Darcy stories, which feature magic operating entirely on scientific principles, a wizard kills himself when trying to kill all the cockroaches in his lab building because his sweat drips in the mixture he’s using.

Basically if you want to make a voodoo doll to curse somebody you better use very clean lab technique, otherwise you’re gonna get dandruff on it or accidentally kill your cat. We know magic doesn’t work that way in D&D though, or wizards would be going beardless and using hairless cats as familiars. Alternately, Magic could work that way, but everyone constantly uses prestidigitation to keep things clean.

[Beleriphon]

On DC systems I like the was Mophidious' 2d20 does things. You're rolling for successes, where what counts as a success is a target number determined by by the character's attributes, while the number of successes is a GM Thing.

[Quertus]

In Randall Garrett’s Lord Darcy stories, which feature magic operating entirely on scientific principles, a wizard kills himself when trying to kill all the cockroaches in his lab building because his sweat drips in the mixture he’s using.

Basically if you want to make a voodoo doll to curse somebody you better use very clean lab technique, otherwise you’re gonna get dandruff on it or accidentally kill your cat. We know magic doesn’t work that way in D&D though, or wizards would be going beardless and using hairless cats as familiars. Alternately, Magic could work that way, but everyone constantly uses prestidigitation to keep things clean.

Or just not cast Genocide spells? That might be the easier answer.

[Hrugner]

In Randall Garrett’s Lord Darcy stories, which feature magic operating entirely on scientific principles, a wizard kills himself when trying to kill all the cockroaches in his lab building because his sweat drips in the mixture he’s using.

Basically if you want to make a voodoo doll to curse somebody you better use very clean lab technique, otherwise you’re gonna get dandruff on it or accidentally kill your cat. We know magic doesn’t work that way in D&D though, or wizards would be going beardless and using hairless cats as familiars. Alternately, Magic could work that way, but everyone constantly uses prestidigitation to keep things clean.

I do like the idea of playing a wizard who is really bad at whatever standard protections are used to prevent these accidents, so he only casts in a "clean room", or uses a magically sealed environmental suit.

[Cluedrew]

Has anyone pinned down what a DC based skill system (or resolution mechanic generally) is? Honestly, the most central thing is actually the one I have the most to say about, which in my mind is the fact you get some score (say from rolling a d20 and adding a modifier to it) and then you compare it to a target number - the DC - for success or failure. The DC is also adjusted to show how hard the task is. But it is that succeed of fail bit that gets me.

The success outcome isn't bad. There are some "jump to the moon" situations which are usually pretty easy to get around with only rolling for possible things. Mostly though "you do the thing you set out to do" works just fine.

The failure outcome is where things get weird. Because "you don't do the thing you tried" is oddly open ended. On one end there is the "nothing happens" outcome where things can stall, set you back to where you were before and why not just go at it again? On the other end there is the "campaigns over" outcome, where the cost of failure is far more than what should be riding on a single roll. This one is a lack of guard rails really, if you are careful it should never come up, but its something you have to watch for.

Finally, there are not in between results. So if you want anything between complete success and complete failure requires multiple checks. It works, and sometimes works quite well, but now you are pretty much putting another resolution system around your existing resolution system and sometimes it is kind of awkward.

[Telok]

I'd have to check through a couple adventures to find the exact reference but there was a Classic Traveller adventure with something like a "roll Computers 9+, +1 for education 10+ and +1 for Bureaucracy skill, for every point you exceed the target number <bonus stuff>, if you fail by 2 or more points <complication>, if you fail by 4 or more <bad thing>". So its not like degrees of success/failure have been unknown for the last 40 years and open ended binary rolls are aren't a solved issue.

[Zuras]

Has anyone pinned down what a DC based skill system (or resolution mechanic generally) is? Honestly, the most central thing is actually the one I have the most to say about, which in my mind is the fact you get some score (say from rolling a d20 and adding a modifier to it) and then you compare it to a target number - the DC - for success or failure. The DC is also adjusted to show how hard the task is. But it is that succeed of fail bit that gets me.

The success outcome isn't bad. There are some "jump to the moon" situations which are usually pretty easy to get around with only rolling for possible things. Mostly though "you do the thing you set out to do" works just fine.

The failure outcome is where things get weird. Because "you don't do the thing you tried" is oddly open ended. On one end there is the "nothing happens" outcome where things can stall, set you back to where you were before and why not just go at it again? On the other end there is the "campaigns over" outcome, where the cost of failure is far more than what should be riding on a single roll. This one is a lack of guard rails really, if you are careful it should never come up, but its something you have to watch for.

Finally, there are not in between results. So if you want anything between complete success and complete failure requires multiple checks. It works, and sometimes works quite well, but now you are pretty much putting another resolution system around your existing resolution system and sometimes it is kind of awkward.

There are a bunch of situations that a simple d20 meet or exceed DC system doesn’t handle. 5e doesn’t give much guidance on basic stuff, other than telling you that you have options. Whether repeated attempts are allowed, consequences for failure (and heightened consequences for failing by 5 or more) are all mentioned, as is success at a cost, failing forward and time considerations in general.

One of the big failings of the 5e DMG is that it basically gives you permission to use whatever cobbled-together hack you think makes sense in a given situation, but doesn’t give any examples. The official published adventures are full of examples, but that’s not helpful to a new DM who’s not running a published adventure.

[Zombimode]

I don't really understand the question and have to echo Cluedrew's question:

Has anyone pinned down what a DC based skill system (or resolution mechanic generally) is?

For "DC based" to be a useful qualifier there needs to be a non-empty complementary set. In other words: what is a non-DC based skill system? Is that even a thing?

To elaborate:
To my knowledge the abbreviation "DC" stands for "Difficulty Class" and was coined by D&D 3e. In that game it marks the target number for a given check. Thus, by setting the DC it is possible to modulate how hard or how easy the task is.

The corollary that I would draw from this is: any skill system in that the task resolution (the "skill check") can be modulated in a way to influence the probability or even possibility of the check to succeed is a DC based skill system. Everything else is just an implementation detail. And thus there are a lot of properties of a skill system that are not the defining line of a DC-based system.

Including:

• If there is a "roll" in the first place or not: even in "you need to be THIS tall to ride" systems the DC can be modulated by lowering or raising the bar
• Whether it is a flat or bell-curve etc. distribution: in 3.5 (flat distribution) a routine task is DC 10, in GURPS (bell curve) a routine task get +4 on effective skill
• Whether there are degrees of success and failure: still failure ends somewhere and success starts somewhere, if that can be modulated it is DC based
• The range of competency (the differences in success rates for amateurs and masters): 5e (small range) vs. 3.5 (big range)
• How the mechanics for retries look like or even exist
• If there is a "mechanic" in the first place: even in purely verbal games tasks can be of different difficulty levels; for an easy task the player has an easy time to convince the GM that the PC succeeds at that task, but has to get much more creative for a hard task

Under that light a "non DC based" skill system is one that uses the exact same check with the exact same range of possible outcomes for every task, equally for everyone.
Like: "whatever you do, flip a coin. If you win the flip, you succeed at what you're trying to do. If you loose, you fail."
I have the feeling that the vast overwhelming majority of game systems do not look like this and have some kind of "DC based" skill system instead.

So, to the OP: assuming that with "DC based skill system" you means something much more specific that what I have detailed above, can you clarify what exactly do you mean?

[King of Nowhere]

clearly the difference between those options is because a skill system can resolve a wide array of wildly different things, ranging from whether you can climb a tree fast enough to escape pursuit, to whether you can get the duke to increase your reward, to whether you can develop a new spell.
and you can't introduce a dozen different subsystems to deal with each of those things separately.
so you get a general system and you adapt it to each specific situation.

[Quertus]

There are some "jump to the moon" situations which are usually pretty easy to get around with only rolling for possible things.

Fortunately, the d20 system in 3e D&D handles jumping to the moon correctly, requiring something like a +1,000,0000,000 modifier or something to succeed - at which point, yeah, sure, why not? Sounds easier than balancing on a cloud, which I feel confident the system lets you accomplish with just a 3-digit DC.

“Always roll, or at least always look at the modifier vs DC, and let the system thereby tell you what is possible”.

And fix any DCs that are problematic (do you really want jumping to the moon to be that much harder than balancing on a cloud, or than using escape Artist to walk through a Wall of Force?)

Has anyone pinned down what a DC based skill system (or resolution mechanic generally) is? Honestly, the most central thing is actually the one I have the most to say about, which in my mind is the fact you get some score (say from rolling a d20 and adding a modifier to it) and then you compare it to a target number - the DC - for success or failure. The DC is also adjusted to show how hard the task is. But it is that succeed of fail bit that gets me.

I don’t think “only success or fail” is actually a property of a DC-based system. For example, multiple modules have multi-outcome Gather Information checks.

And I usually house rule a “made it by X / Failed by X” state into any DC based system. Which I still consider to be DC-based systems, even after my mods.

The success outcome isn't bad. There are some "jump to the moon" situations which are usually pretty easy to get around with only rolling for possible things. Mostly though "you do the thing you set out to do" works just fine.

The failure outcome is where things get weird. Because "you don't do the thing you tried" is oddly open ended. On one end there is the "nothing happens" outcome where things can stall, set you back to where you were before and why not just go at it again? On the other end there is the "campaigns over" outcome, where the cost of failure is far more than what should be riding on a single roll. This one is a lack of guard rails really, if you are careful it should never come up, but its something you have to watch for.

Finally, there are not in between results. So if you want anything between complete success and complete failure requires multiple checks. It works, and sometimes works quite well, but now you are pretty much putting another resolution system around your existing resolution system and sometimes it is kind of awkward.

Huh. Ok, tying everything together, I guess your question is, “is it still a DC system if you have multiple DCs or a gradient of success”; ie, if a knowledge check isn’t “do you know…” but “how much do you know”, like those multi-DC Gather Information checks.

And while my impulse has been to say, “yes”, then it makes the category rather large.

And I’m cool with that.

its not like degrees of success/failure have been unknown for the last 40 years and open ended binary rolls are aren't a solved issue.

Yeah, it’s funny how easy it is to get trapped into just a single way of looking at things.

And this thread, talking about common issues, simply exacerbates that mindset. There’s nothing intent to a DC system that it should have these problems, regardless of how common they are.

If there is a "roll" in the first place or not: even in "you need to be THIS tall to ride" systems the DC can be modulated by lowering or raising the bar

Huh. I hadn’t considered that. I guess such systems could be DC, but, depending on implementation, they could also be Gatekeeping.

For "DC based" to be a useful qualifier there needs to be a non-empty complementary set. In other words: what is a non-DC based skill system? Is that even a thing?

For a few example of things that aren’t DC systems….

WoD uses “DC and successes” dice pools, as well as just “successes” dice pools. As does Shadowrun.

Star Trek has a couple of Systems which just have “roll under”. In Call of Cthulhu, I’ve only experienced “roll under skill” and “roll under half/double skill”.

D&D 3e has Gatekeeping, where only trained Rogues can use Search to find magical traps, or some skills can only be used when Trained.

And of course there’s always “player skill” challenges.

[Cluedrew]

The corollary that I would draw from this is: any skill system in that the task resolution (the "skill check") can be modulated in a way to influence the probability or even possibility of the check to succeed is a DC based skill system.

I think this one is a little too broad. Scratch that, this is way too broad. It covers every single resolution system in a role-playing game I've ever heard of except Toon's "what do we do if we don't know what a rule means" decider. Which is not to say others don't exist but its pretty rare. I would argue some of those details are important.

Some things that I would say makes it not a DC based system:

• Your score is not determined by the some of dice/a die and a modifier. This is probably is one of the less important ones but someone pulled out a dice pool system as an example of a DC system I would be surprised.
• The target number does not represent difficulty; either being fixed or adjusted for some other factor. For example, if the dice are set by the difficulty of a task and then you have to roll equal to or under your skill level, that would not be a DC.
• There are multiple target numbers. If you grade success by which thresholds are passed that is something else. Here you could argue there is a difference between not-a-DC and DC-with-add-on, but if an add on is core to the system and used all the time, I'd say it is a different system.

To Quertus: My argument is that a multi-check system is not a DC system, but a larger system that uses a DC check as a component. Which is not an inherent problem if done correctly, but it does add more points of failure because even if you get the DC system right you could mess up the system for combining the results or deciding which one to use.

[Zuras]

I don't really understand the question and have to echo Cluedrew's question:


For "DC based" to be a useful qualifier there needs to be a non-empty complementary set. In other words: what is a non-DC based skill system? Is that even a thing?

There are lots of skill systems not based on DCs. Many systems have a target number set by the character’s skill, or even a system set number for success. Savage Worlds always registers a success on a 4 or higher, but hitting a 4 is much more likely on a d10 than a d4, for example. There are also lots of roll-under your stat/skill systems, particularly in the OSR.

Now, in theory the math can be equivalent if you apply penalties to the skill roll based on task difficulty, but psychologically it feels different, and GMs tend to stick to a smaller range and are less likely to throw a DC 20 ladder at you.

Also, the discussion began in response to people slagging the Pathfinder 2e and D&D 5e skill systems. My question in response was basically “what problems do you see with the d20 DC skill system (as seen in D&D 3.0 and greater, Pathfinder, and other places) that are inherent to the system and not just bad/inexperienced GMs making trees switch between impossible to climb and basically ladders on alternating Thursdays.

Some of the issues may be universal to all skill system, like “I don’t have a satisfying heuristic for deciding when to roll group checks versus individual checks, and I worry I’m not being consistent”. Others may be system-specific, but not actually related to DC based systems, like the lack of a bell curve in any skill check resolved by a single d20, which every 2d6, 3d6, 4dF, and Nd6 system avoids.

Phrased another way, “as a GM, what problematic habits do you keep on falling into when resolving skill contests in D&D and Pathfinder, and/or what types of more complex contests do you wish you had additional rules guidance to resolve rather than having to steal a mechanic from another game (or a previous module you played)?”

[Quertus]

I think this one is a little too broad. Scratch that, this is way too broad. It covers every single resolution system in a role-playing game I've ever heard of except Toon's "what do we do if we don't know what a rule means" decider. Which is not to say others don't exist but its pretty rare. I would argue some of those details are important.

Some things that I would say makes it not a DC based system:

• Your score is not determined by the some of dice/a die and a modifier. This is probably is one of the less important ones but someone pulled out a dice pool system as an example of a DC system I would be surprised.
• The target number does not represent difficulty; either being fixed or adjusted for some other factor. For example, if the dice are set by the difficulty of a task and then you have to roll equal to or under your skill level, that would not be a DC.
• There are multiple target numbers. If you grade success by which thresholds are passed that is something else. Here you could argue there is a difference between not-a-DC and DC-with-add-on, but if an add on is core to the system and used all the time, I'd say it is a different system.

To Quertus: My argument is that a multi-check system is not a DC system, but a larger system that uses a DC check as a component. Which is not an inherent problem if done correctly, but it does add more points of failure because even if you get the DC system right you could mess up the system for combining the results or deciding which one to use.

You’re drawing the line at multiple rolls? I mean, as much as it’s in character for me to poke fun at 4e for what it isn’t, I’d still argue that 4e skill challenges are DC based. Well, a really odd “DC and successes” wuzzle, with an emphasis on DC, whereas (some rolls in some editions of) WoD involved a simple hybrid “DC and successes”, with an emphasis on successes.

Which leads us to your other criteria.

Dice pool systems absolutely can use a variant DC; they just usually are primarily about things like “successes”. Still, if you sum your die pool, it becomes a little more obvious how “die pool” and “DC” can interact, no?

Similarly, I think… I think humans are mammals. As are horses. We need those three words to describe those two things, because one is a container for the other two.

In that vein, I can see the desire for the capacity for distinguishing “pure DC” systems from hybrid ones, sure. But they’re all still in the larger umbrella of “uses DC”.

Now, 3e is the origin of popular usage of DC, no? Which provides us with our two strong, competing interests. On the one hand, we’d want 3e to fall inside the DC label on a Venn diagram; otoh, it’s got numerous resolution tricks, that one would want to be able to have individual names for.

And it’s not just Gather Information in a few modules - craft checks have variable DCs producing variable speed crafting; I think Climb and Spellcraft have similar speed boosting variable DCs; Hide is opposed by Spot; Sleight of Hand has variable DCs for success and whether the attempt was spotted (successful or no); Knowledge checks aren’t binary “know nothing / know everything” checks; etc.

So, since 3e is rife with so many resolution tricks in its skill system, I’d propose to put everything in 3e skill checks into the huge DC umbrella by default, and individually label the various subsystems, removing those (like “opposed rolls”) that explicitly don’t fit under this umbrella.

[Tanarii]

The corollary that I would draw from this is: any skill system in that the task resolution (the "skill check") can be modulated in a way to influence the probability or even possibility of the check to succeed is a DC based skill system.

No it's not. A percentage based system where success equals your ability score plus training, task resolution modulated by difficulty by bonus or penalty up to the GM, is not a DC-based skill system.

Nor is D&D NWP system, roll under ability score, with difficulty modulated as a penalty to the ability score by the DM.

Even one where ability scores + training determine number of dice vs a static TN (ie dice pools), task resolution modulated by difficulty by bonus or penalty up to the GM by adding or subtracting dice, is not a DC-based skill system.

Even one that uses dice pools with a variable TN being modulated by the GM still isn't a DC-based skill system.

The defining characteristics of a DC based skill system are:
D20 rolled
With bonuses from training and natural skill/focus (some combination of proficiency and ability score)
TN set by GM within recommended range (the "DC")
Roll above TN (ie higher roll is better)

[NichG]

As far as non-DC skill systems I would say (not a comprehensive list):

- Systems that aren't about resolving questions of success or failure
- Systems in which skill investiture unlocks fixed things that the character can then just do without a 'check'
- Systems in which skills determine and scale passive perks that apply to the character - for every point of Athletics you can run 5% faster, etc.
- Systems in which task difficulty is not determined but is emergent, and skills/rolls give you a means to navigate that. E.g. bidding systems, systems with side effects and buying off side effects. Imagine e.g. playing chess but where your skill rating sometimes lets you cheat or make pieces move differently than the normal rules, and the same is true of your opponent.
- Systems where skills determine a pool of points or resources that can then be used for things going forward - Draw as many Sword Moves as your Kendo skill rank, ... Or 'roll Stealth to see how many times during this infiltration you can pass through a guard's sight line without being spotted'

[Satinavian]

For me a "skill based DC system" was always something where you roll something based on your skill (skill bonus, dice pools growing with skill etc, whatever) and compare against a number representing the Difficulty of the task at hand (and also allowing degrees of failure success, not only pure binary outcomes).


That is obviously far far broader than the D&D group of skill systems which i all hold not in high regard.

[MetroAlien]

one of the more interesting systems I know is in the German RPG "the dark eye" (Das Schwarze Auge)
I'm running off my foggy memory from many years ago, so feel free to correct me.

"attribute" and "skill" ranks are completely separate, iirc

rolling a DC on a skill may involve up to 3 attributes.
the player must roll lower than each of their attribute scores.
(I think attributes are capped at 20 to represent critical failure)
the player can use their skill ranks to offset the rolled dice.
the equivalent of DC is assigned by the DM as bonus/penalty to the skill rank

for example,
rolling a "climbing" check [5 ranks + 3 for easy DC],
with "Dexterity" [11, rolled 8],
"Strength" [13, rolled 17]
and "Constitution" [11, rolled 12]
the player then can use up to a total of 8 points to bring the "CON" roll down to a 10 and "STR" to 12 and succeed.

I forget if the number of successes was important or not.

[Cluedrew]

YouÂ’re drawing the line at multiple rolls? I mean, as much as itÂ’s in character for me to poke fun at 4e for what it isnÂ’t, IÂ’d still argue that 4e skill challenges are DC based. Well, a really odd "DC and successes" wuzzle, with an emphasis on DC, whereas (some rolls in some editions of) WoD involved a simple hybrid "DC and successes", with an emphasis on successes.

Yes, I would describe that, and similar systems of combining results are not DC systems because you could swap out how the component check works and the aggregate system work work the same way. Or if you want to focus on just the implementation that combines DC checks: The difference between one and multiple feels significant that should be acknowledged.

And yeah, there are parallels between this resolution system and others, but that doesn't mean they are the same.

The defining characteristics of a DC based skill system are:
D20 rolled
With bonuses from training and natural skill/focus (some combination of proficiency and ability score)
TN set by GM within recommended range (the "DC")
Roll above TN (ie higher roll is better)

Pretty much this yes, I might explicitly add that the "DC" represents the difficulty of the task and I don't care what you call the numbers that go into your modifier, just as long as it represents the character's ability to do the thing. It is probably excessive around here, but in general you can have other inputs that represent other things. (Blades in the Dark for instance cares more about risk than difficulty.)

This sort of goes against what I said about the random number before. I think I do care about the random method in I think it has to be uniform. I don't think a d20 is needed, a d10 would work just fine too. But the uniform distribution feels pretty important, I can remember debates between the sides of uniform vs. bell curved (which is rarely sharp enough to look like an actual bell curve).