Adjusting Difficulty
Source GM Core pg. 52
You might decide a DC should differ from the baseline, whether to account for PCs' areas of expertise or to represent the rarity of spells or items. A DC adjustment represents an essential difference in the difficulty of a task and applies to anyone attempting a specific check for it. Adjustments happen most often with tasks whose DCs are based on their level. You'll often apply the adjustments for uncommon, rare, or unique subjects.
The DC Adjustments table lists the categories of adjustments. The adjustments' names are relative to the base difficulty of the task itself—a very hard 2nd-level task will not be “very hard” for a 10th-level PC to accomplish! PCs who invest in a skill will become better and better at that skill as they increase in level. For example, even the best 1st-level PC has grim odds against an incredibly hard 1st-level DC, with a huge chance of critical failure, but by 20th level, an optimized character with a modicum of magic or assistance can take down incredibly hard 20th-level DCs over half the time, critically failing only on a 1. At higher levels, many groups will find that the very hard DC is more like standard for them; keep that in mind if you need a check that presents a true challenge to a high-level group.
You might use different DCs for a task based on the particular skill or statistic used for the check. Let's say your PCs encounter a magical tome about dragons. The tome is 4th-level and has the arcane trait, so you set the DC of an Arcana check to Identify the Magic to 19. As noted in Identify Magic, other magic-related skills can typically be used at a higher DC, so you might decide the check is very hard for a character using Occultism instead and set the DC at 24 for characters using that skill. If a character in your group had Physical Science Lore, you might determine that it would be easy or very easy for them to use that skill and adjust the DC to 17 or 14. These adjustments aren't taking the place of characters' bonuses, modifiers, and penalties—they are due to the applicability of the skills being used.
The DC Adjustments table lists the categories of adjustments. The adjustments' names are relative to the base difficulty of the task itself—a very hard 2nd-level task will not be “very hard” for a 10th-level PC to accomplish! PCs who invest in a skill will become better and better at that skill as they increase in level. For example, even the best 1st-level PC has grim odds against an incredibly hard 1st-level DC, with a huge chance of critical failure, but by 20th level, an optimized character with a modicum of magic or assistance can take down incredibly hard 20th-level DCs over half the time, critically failing only on a 1. At higher levels, many groups will find that the very hard DC is more like standard for them; keep that in mind if you need a check that presents a true challenge to a high-level group.
You might use different DCs for a task based on the particular skill or statistic used for the check. Let's say your PCs encounter a magical tome about dragons. The tome is 4th-level and has the arcane trait, so you set the DC of an Arcana check to Identify the Magic to 19. As noted in Identify Magic, other magic-related skills can typically be used at a higher DC, so you might decide the check is very hard for a character using Occultism instead and set the DC at 24 for characters using that skill. If a character in your group had Physical Science Lore, you might determine that it would be easy or very easy for them to use that skill and adjust the DC to 17 or 14. These adjustments aren't taking the place of characters' bonuses, modifiers, and penalties—they are due to the applicability of the skills being used.
Group Attempts
Source GM Core pg. 52
The DCs in this chapter give an individual character a strong and increasing chance of success if they have some proficiency. On occasion, though, you'll have a task that only one person in the group needs to succeed at, but that everyone can attempt. The number of dice being rolled means that there's a very high chance at least one of them will succeed. Most of the time, that's perfectly fine, but sometimes you'll want the task to be a challenge, with some uncertainty as to whether the party can succeed. In these cases, make the check very hard or incredibly hard if you want it to be particularly difficult or at high levels. At these DCs, most of the party will probably fail, but someone might still succeed, likely a character who has heavily invested in the given skill, as is expected for specialized characters.
DC Adjustments
| Difficulty | Adjustment | Rarity |
|---|---|---|
| Incredibly easy | –10 | — |
| Very easy | –5 | — |
| Easy | –2 | — |
| Hard | +2 | Uncommon |
| Very hard | +5 | Rare |
| Incredibly hard | +10 | Unique |