Pathfinder 2e - Practical Guide to Assurance
Last Updated: January 23rd, 2020
Assurance is a general skill feat which you can take with any skill. It's intended provide a reliable way to use a skill without risking failure due to a low roll. However, the wording of the feat and the way skill modifiers increase make it unclear whether or not Assurance is worthwhile.
In this article we'll explore the rules around how Assurance works, and the math comparing it to a normal ability check. But don't worry, I'll use lots of graphs to make it easy to understand if you're not math-inclined.
How Assurance Works
Let's start by looking at the exact wording of the Assurance feat.
Choose a skill you’re trained in. You can forgo rolling a skill check for that skill to instead receive a result of 10 + your proficiency bonus (do not apply any other bonuses, penalties, or modifiers).
The text in parentheses is extremely important, but easy to forget. While you do get to ignore penalties from things like Enfeebled or other status conditions, you also ignore your own ability modifier, as well items from other sources like magic items, the Aid action, the Guidance spell, or any number of other sources.
That immediately raises some concerns: Typically skills in which you want to take Assurance are skills which you're using a lot and can't risk railure, but without your Ability Modifier your total modifier is drastically reduced even we never consider other modifiers.
Is Assurance better than rolling?
In some circumstances, yes.
In a typical circumstance where you have no temporary modifiers and you're making a Skill Check, Assurance is mathematically worse than just rolling for a check unless you have a negative Ability Modifier. Even if you have penalties on the check, they still need to make the sum of all of your modifiers except your Proficiency Bonus negative before Assurance is mathematically better than a normal Skill Check.
Assurance also shines with skills that have flat DCs for specific uses. Medicine's Treat Wounds has a flat DC of 15, so a 3rd-level character Trained in Medicine can meet the DC guaranteed with Assurance. As your proficiency increases you can hit gradually higher DCs without investing in Wisdom, items, or anything else that you would normally need to get a decent skill modifier. Add on a few skill feats and Skill Increases and you can do quite a bit of healing non-magically.
For comparison, consider the graph below. Because we're comparing a normal roll to Assurance, the Proficiency Bonus has been omitted because it adds the same value to both options.
The horizontal blue line indicates the "average roll" for assurance, which is a static 10. The orange line marks your average roll on a typical skill check with various modifiers along the graph's x-axis. The vertical lines extending from the orange line indicate the maximum and minimum rolls with that modifier. And to reiterate: we're ignoring Proficiency because it adds the same amount to both a roll check and to Assurance, and we only care about the difference between the two.
If we ignore the affects of rolling a Natural 1 or a Natural 20, we can draw some interesting conclusions. As I mentioned above, a modifier of +0 will beat Assurance on average (10.5 vs. 10; 55% chance to exceed Assurance), and as your modifier improves you're more likely to roll higher than the 10 granted by Assurance. At a +9 modifier on a natural 1 you still match Assurance (ignoring the effects of rolling a natural 1). Each +1 modifier increases you're changes of exceeding Assurance by 5%.
A typical character with have a +4 Modifier in their Key Ability Score and a +3 in other important Ability Scores. Right from 1st level, if you have Assurance in a skill which relies on those abilities you have a 75% or 70% chance to beat Assurance, making rolling the mathematically sensible way to get a higher roll.
Even a +9 modifier is easily achievable. A character with a +5 ability modifier (easily achievable by level 10), a +3 weapon, and a +1 bonus from somewhere else can use a weapon to make an Athletics check to trip at a +9 modifier.
Is Assurance Good?
The graph above doesn't give us a full picture of whether or not Assurance is useful. The benefit of Assurance is that you can always choose to take the same result on a check regardless of circumstances. If that result is enough to pass a check and you don't want to try for a Critical Success, Assurance is not only useful it can be a wonderful insurance policy.
Assurance vs. Level-Based DCs
The rules for Game Masters suggest several methods for setting check DCs, including level-based DCs. While your GM might opt for the "Simple DCs" option, the level-based DCs provide a useful thought exercise, and it's useful for a mathematical comparison between Assurance and the Level-Based DC progression.
As you can see in the graph, the level-based DC progression doesn't neatly follow the increase in Proficiency bonuses. I'm not entirely certain why that's the case, but I'm sure someone at Paizo had a clever reason for it. You may also notice that Assurance is consistently lower than the Level-Based DC at the same level. They match at levels 7 and 8 for some reason, but that's the best it gets.
However, all hope is not lost. The rules for balancing encounters generally pit the party against one or more creatures below the party's level, and the DC for Recall Knowledge is based on the creature's level. Assurance consistently meets or exceeds the Level-Based DC one level lower, so if you have Assurance in a skill where you're maximizing your Proficiency, you can consistently overcome many skill DCs using Assurance. This may be enough to justify Assurance in skills like Arcana, Nature, Occultism, and Religion so that you can rely on Recall Knowledge to identify monsters. Unfortunately, Assurance is consistently behind the Level-Based DCs for spells, so you can't rely on it to identify spells being cast.
Assurance in Combat
Perhaps the most important use of Assurance is in combat, where skills introduce options like Athletics to Trip, Deception to Feint, and Intimidation to Demoralize. These can be central combat options for your build, so the ability to rely on them is fantastic.
When you make these checks, they're made against the target's saving throw DCs. This means that when you use Assurance, you're measuring 10 + your Proficiency against 10 + the target's Proficiency + the target's Ability Modifier. That's not a great equation for the player, unfortunately, but again: all hope is not lost.
Remember: most enemies that you face will be of a lower level than you, so their Proficiency Bonus will often be lower than yours simply due to the level difference. You also have the option of choosing how proficient you are in a skill, and saving throw proficiencies may not increase as early or as much as your skill proficiency. If you're maximizing a skill, that will often put you ahead of the target's Proficiency in the type of save that you're targeting.
Where you run into trouble is the target's Ability Modifier. The gap between your proficiency and the target's proficiency needs to be larger than the target's Ability Modifier. That can be hard to count on, but in encounters with numerous enemies below your level you can generally count on their saving throw DCs being lower than your Proficiency Bonus in a skill that you're maximizing.
Perception follows similar logic to saving throws, and since players most frequently oppose Perception with Stealth, choosing Assurance in Stealth can allow you to consistently succeed on Stealth checks when failure often means finding yourself in combat while separated from your party. It also means that you can use Stealth to get a consistent result on Initiative if you can hide before combat begins.
Finally, because Assurance ignores all bonuses/penalties except your Proficiency Bonus, it also ignores Multiple Attack Penalties. So if you have Assurance in Athletics, you can easily use your second or third Action to make a special attack like a Shove without suffering the massive Multiple Attack penalty from having made one or more attacks beforehand.
Assurance is useful against level-based DCs and foes which are below your level, assuming that you're increasing your Proficiency with the skill as early and as often as possible. This means that you likely only want Assurance in one or two skills, and even then only if you're going to use that skill very frequently.
Against threats and challenges of your level or higher, expect to roll. Assurance might still work against enemies of your level, especially if you're targeting saves where the creature is weak (Reflex saves are often low on big, burly foes like Ogres), but generally you should expect to roll in these cases. Fortunately, you're still more likely to succeed than fail, but you can't perfectly rely on beating Assurance until you're very high level and have a big bonus to throw around.