# In Pathfinder 1e, does damage accumulate for the purpose of calculating Concentration Checks with Injury

Here is the scenario: A party has been giving chase to a spellcaster and corners them in an alley. Initiative is called for, and two archers in the party with higher initiative than the spellcaster decide they are both going to ready their actions of shooting their bows, to be triggered if the spellcaster begins to cast a spell.

On the spellcaster's initiative, the spellcaster attempts to cast Dimension Door(a level 4 spell), triggering the attacks of both archers. Both archers make their To Hit rolls, and the 1st archer does 3 points of damage and the 2nd does 5 points of damage.

My question is about the Concentration Check formula, which states:

If you take damage while trying to cast a spell, you must make a concentration check with a DC equal to 10 + the damage taken + the level of the spell you’re casting.

It is my understanding that the spellcaster needs to make two concentration checks, one for each source.

For the first concentration check, the formula would be: 10 + 3(damage taken) + 4(level of spell) = 17.

*** For the second concentration check, is the damage from the second arrow treated as separate damage or does it accumulate? ***

In other words, should it be: 10 + 5(damage taken) + 4(level of spell) = 19.

or: 10 + 3(damage taken from arrow number one) + 5(damage taken from arrow number two) + 4(level of spell) = 22.

In my opinion, the additional damage should accumulate, meaning the more incoming damage, the more difficult to concentrate on the completion of the spell?

All my efforts to find an answer only talked about different damage types, but nothing on accumulating damage.

If it does NOT accumulate, can you cite something in the rules, or state whether this is opinion?

Thoughts?

• Welcome to RPG Stack Exchange! Take the tour if you haven't already, and check out the help center for additional help. Oct 3, 2023 at 8:58

## No, it does not accumulate.

Instead, the added difficulty is represented by having to make multiple checks. If he fails any of the checks, the spell also fails.

If you take damage while trying to cast a spell, you must make a concentration check with a DC equal to 10 + the damage taken + the level of the spell you’re casting. If you fail the check, you lose the spell without effect. The interrupting event strikes during spellcasting if it comes between the time you started and the time you complete a spell (for a spell with a casting time of 1 full round or more) or if it comes in response to your casting the spell (such as an attack of opportunity provoked by the spell or a contingent attack, such as a readied action).

Concentration

With how to find this in the rules - there are no hidden rules. Since the rules never talk about accumulating, there is no accumulation.

• Lack of discussion about accumulation doesn't rule it out. I agree that there are multiple checks involved, but I contend that in addition to the caster having to succeed on multiple checks, each check should become more difficult due to additional damage as well. Picture a movie where someone or something is approaching a person shooting them with a gun. Each time they get hit slows them down just a little bit more than before, until finally they stop altogether. That is what I am picturing anyway. Oct 3, 2023 at 13:39
• Each check is independent of the other. The damage of the previous attack (or the one before that, or the one before that) is not remembered in anyway other than just the current total of hit points is less than the maximum. Oct 3, 2023 at 14:47
• The momentum of a bullet is insignificant compared to someone trying to rush someone else. If they stop, it's because of the pain or because they're incapacitated otherwise. In the game, this is simulated with your HP falling below zero. In fact, one could argue that it should be easier to ignore arrow #5 than arrow #1 - there's little added shock/surprise. Oct 4, 2023 at 9:18

## Each source of damage causes a separate concentration check

The rules say:

If you take damage while trying to cast a spell, you must make a concentration check with a DC equal to 10 + the damage taken + the level of the spell you’re casting. If you fail the check, you lose the spell without effect. The interrupting event strikes during spellcasting if it comes between the time you started and the time you complete a spell (for a spell with a casting time of 1 full round or more) or if it comes in response to your casting the spell (such as an attack of opportunity provoked by the spell or a contingent attack, such as a readied action).

Each attack of opportunity is its own interrupting event, so each is handled with its own separate concentration check. You take damage from an attack when it hits (after applying damage reduction and other effects that reduce damage), so each attack has its own "damage taken":

If your attack succeeds, you deal damage.

This is similar to the handling in related situations, like when you cast a spell that has multiple damage events, such as scorching ray.

• Each source of damage, the two bows shots, are causing multiple concentration checks, and we all agree on that. But, 'the damage taken' part of the formula doesn't specify if it is from the source or from all sources. It is just vague enough to be argued one way or the other. This is why I am arguing for accumulated damage. Oct 3, 2023 at 13:42
• @TonyMosconi The "damage" referred to in the formula is specifically taking about the damage taken from the interrupting event. If it was meant to be accumulated damage it would have been worded more like "total damage taken this turn" or "total damage from all attacks triggered by the casting". Oct 3, 2023 at 14:53
• @MichaelRichardson - I agree with your interpretation of this rule, but as there are so many other places where the lack of detail creates similar vagueness, opening the door for discussion, I believe this is also one of those rulings. Oct 3, 2023 at 15:56
• In my scenario, the caster takes damage from two separate attacks, after casting has started, but before it completes. As there is no plural to the word 'damage', it could easily imply that after taking the second arrow to the knee, the damage in the formula now refers to all damage that has been taken since casting had begun. Simply saying that this is not a possible interpretation because the author would have said if if they wanted it that way is faulty logic. Nevertheless, the DM will get the final ruling, right? Oct 3, 2023 at 15:56
• @TonyMosconi The DM can do whatever they decide, until his players have had enough and look for a different DM. In this case, as just one check is probably to their advantage (would need to do the math), I don't see a lot of risk for that. Oct 3, 2023 at 16:49