Is the DC table applied to characters with or without proficiency?

Question

In the PHB there is a section on typical difficulty classes:

Difficulty	DC
Very easy	5
Easy	10
Medium	15
Hard	20
Very hard	25
Almost impossible	30

Just looking at the numbers, I would say that an average person failing at an easy task 50% of the time is somewhat strange, so have always assumed that these scores are taking proficiency into account.

As a result when people suggest making an Intelligence check, rather than Intelligence (Arcana) I don't like that because it makes the check statistically harder. IE: I assumed this table was meant to account for proficiency and skill use, rather than just raw ability scores.

However it has recently been suggested to me that these are the default DC's for the untrained, so what is actually happening is that proficiency makes the task easier.

So:

When looking to set a DC for a check, if I was going to not include proficiency, would I still use the same table, or should I adjust the value down to account for my DM decision not to allow a skill proficiency?

Answer 1

The rules assume you are not proficient

To quote page 239 of the DMG:

[...] Keep in mind that a character with a 10 in the associated ability and no proficiency will succeed at an easy task around 50 percent of the time. A moderate task requires a higher score or proficiency for success, whereas a hard task typically requires both. [...]

Because it explicitly lists being proficient as a way of increasing your odds, we can conclude that it does not assume you are proficient. To put this another way, that sentence simply cannot make sense if the rules had assumed you were proficient.

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Each task has only one DC associated with it

To quote that same page of the DMG:

When you [establish the Difficulty Class for an ability check or a saving throw], think of how difficult a task is and then pick the associated DC from the Typical DCs table.

Thus, we know that when setting the DC for a task, it is the same DC value regardless of proficiency. The same table is used for anyone attempting the task, even those not proficient. Proficiency in a skill simply means you accomplish the task more easily (or more frequently). The difference in the difficulty of a task when attempted by a proficient individual and a non-proficient individual does not come from the DC changing but from the proficient individual being better at the task.

The difficulty dictates whether you might need proficiency (or how much you might want for it). Proficiency means you are more likely to succeed at a Hard task, and makes Easy tasks become almost (or entirely) trivial.

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That said, do keep in mind that words like "Easy" and "Medium" change as you progress through the game. That same page states:

[...] If you find yourself thinking, "This task is especially hard," you can use a higher DC, but do so with caution and consider the level of the characters. A DC 25 task is very hard for low-level characters to accomplish, but it becomes more reasonable after 10th level or so. A DC 30 check is nearly impossible for most low-level characters. A 20th-level character with proficiency and a relevant ability score of 20 still needs a 19 or 20 on the die roll to succeed at a task of this difficulty. [...]

Answer 2

I think part of this is a matter of perspective.

While the chart refers to an "Easy Task", it's not talking about tying your shoes. DMs (generally) don't make a character roll for that stuff.

The chart is for:

• did the character pick a lock successfully
• did the character stick the landing
• can the character find a good place to hide

In the PHB it says:

An ability check tests a character's or monster's innate talent and training in an effort to overcome a challenge. The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure. When the outcome is uncertain, the dice determine the results.

Using picking a lock as an example, I have no training, but if it's a simple combination lock, I might get lucky and feel the clicks while turning. But someone proficient with locks would have tools (and know how to use them) to make the job easier.

The same could be said for other checks. Someone proficient in Medicine would be at diagnosing a medical issue than just random person on the street. But random person might still get lucky.

So don't think "easy" means easy for everyone. It's easy for someone that has a background in whatever skill is being used.

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Taking into account the editing of the question:

Like everything else in 5e, it all boils down to three things: preparation, probability, and winging it.

As a DM, set the DC to what makes sense for the situation and the characters involved. Higher level characters have more tools and experience at their disposal than those just starting out. So if you want the characters to succeed, set the DC low. If you want it to be a challenge, set it high.

Just remember, PCs are supposed to be "better" than the average creature; stronger, smarter, innate magic, etc. So the DC needs to reflect that not only is your Barbarian trying to break open the door, but so could Timmy, the bartender. If you put the DC too low, then what was the point of getting proficiency in the first place?

Answer 3

The difficulty represented by the DC doesn't change based on whether a character is proficient or not; being proficient intentionally makes them more likely to succeed on a given task, as does having a better than average score in the relevant Ability.

Remember that an average, non-proficient person rolling for an Easy task is still attempting to do something non-trivial, for which they have no particular aptitude or training. As the PHB says just before the table you cite:

The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure.

So they wouldn't be rolling at all if the task was trivial. In that sense, the descriptor "Easy" represents the difficulty as someone proficient would see it, though even they would only be rolling if there is some reason to suspect they would fail.