Multiple sources of miss chance, do they stack?


Rules Questions


OK if I have a Barghest using blink and he was in dim light to begin with, would you stack the two miss chance sources for a total of 70% miss chance?

Or would it just be the greater of the two.

Trying to come up with a fair ruling for this situation.


No. I am not home now so I will have to provide the source later.


nope just like how fortification doesnt stack


I was under the impression that they all applied separately.

For example if you had a 50% miss chance and a 20% miss chance, first you would roll one, then the other.

Mathematically this 50% then 20% would give you an effective 60% miss chance, not 70% as if you added them.


This thread argued it a lot before with no agreement. Thread

I personally would roll a concealment miss chance (max 50%). And then follow with any non concealment miss chance, such as the portion of blink that comes from not being there.

The Exchange Owner - D20 Hobbies

They don't stack


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Quote:
Concealment Miss Chance: Concealment gives the subject of a successful attack a 20% chance that the attacker missed because of the concealment. Make the attack normally—if the attacker hits, the defender must make a miss chance d% roll to avoid being struck. Multiple concealment conditions do not stack.

The Exchange Owner - D20 Hobbies

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+1 wraithstrike rocking put the legit rules answer I couldn't find.


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Multiple concealments don't stack... But what if one of the miss chances are not caused by Concealment?


Miss chance = concealment


Tabernero wrote:
Multiple concealments don't stack... But what if one of the miss chances are not caused by Concealment?

This is not covered directly by the rules because it is so rare*. I would still follow the miss chance concealment rules, but outside of that it falls to the GM to decide if he wants to do so or not.

*I think only one spell offers it, and that is displacement.


Entropic shield also grants a miss chance by deflecting incoming arrows.
It acts similar to concealment, but is not itself concealment. So that's at least two core spells that grant a mischance that is not fully concealment (blink being the other).

The rules are clear that multiple concealment conditions don't stack.

If it's not a concealment condition, then make a second roll. Also James Jacobs will tell you himself (he has told me many times) that he is not a rules guy so take his suggestions for what they are.


For sake of example let's say you have Displacement (50% miss chance due to concealment), blur (20% miss chance due to concealment), and entropic shield (20% miss chance not due to concealment, it deflects 20% of attacks).

We should all agree that the displacement effect makes the blur effect moot, based on the rules quoted above. "Multiple concealment conditions do not stack." So there is a 50% miss chance due to concealment.

But there is still a 20% chance that an incoming arrow, that would normally hit, may be deflected by the entropic shield. This should not be simply forgotten.

The 50% and the 20% would not add up to a 70% miss chance, that's not how numbers work. Mathematically a 50% miss chance followed by a 20% miss chance, gives an overall miss chance of 60%. So you do get some diminishing returns, which is exactly how it should be.


Now if you stacked Displacement, Blink, and Entropic Shield.....

You would have a 50% miss chance from concealment, followed by a 20% miss chance because you are on the ethereal plane at the moment (part of blink is concealment, how much is debatable but let's use the worst case), followed by a 20% miss chance due to the shield deflecting the attack.

Mathematically this give you a 68% overall miss chance, not crazy for having 3 short term buffs up. And certainly not the 90% you would get if you added the percentages together.


Math is hard.

The Exchange Owner - D20 Hobbies

Funny that people keep saying James Jacobs isn't a rules guy but he's like batting 99% success rate in predicting FAQ answers before they get published. Often by years.

There is no reason to jump to "Mathmatically this gives you" or anything other than:
Roll a percentage.
Does this pass all the relevant miss chances and concealments?
If so, you hit.

All this shouldn't stack.

Keep in mind the stacking rules only cover "spells", yet we know that gets extended to even non-magic things like virtual size increases from things like spiked shields. So having "concealment" extended to cover non-concealment miss chances should be the same kind of thing.

Shadow Lodge

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James Risner wrote:
Funny that people keep saying James Jacobs isn't a rules guy

Including James Jacobs


For there has always been the chance of how Mirror Image applies within this context.

I believe I try to run it as mirror image roll first, if you miss you destroy a duplicate as normal, if you "hit" you roll against normal miss chance.


Are mirror images 'blurred'?

Also, displacement technically isn't concealment, it just has a miss chance 'as if' it were total concealment. You would still provoke AoOs for example.

Also, blink is partially concealment (20%) and partially being ethereal. If the concealment doesn't stack, you would still get the extra miss chance for being ethereal (20%).

Actually, the blink percentages don't really add up to 50%, so I'm not quite sure how they did their math.


Mirror images are blurred but they are not considered a miss chance effect. That is why they work with spells that call out miss chance.


wraithstrike wrote:
Mirror images are blurred but they are not considered a miss chance effect. That is why they work with spells that call out miss chance.

Yeah, I was wondering why mirror images don't get a miss chance.

The Exchange Owner - D20 Hobbies

TOZ wrote:
James Risner wrote:
Funny that people keep saying James Jacobs isn't a rules guy
Including James Jacobs

Even funnier that for years he was the official rules FAQ guy for non-PDT products.

Liberty's Edge

Pathfinder Adventure, Adventure Path, Companion, Lost Omens, Rulebook Subscriber
James Risner wrote:
TOZ wrote:
James Risner wrote:
Funny that people keep saying James Jacobs isn't a rules guy
Including James Jacobs
Even funnier that for years he was the official rules FAQ guy for non-PDT products.

He is the official rule guy for Golarion products. AFAIK he is the guy that manage that section of the FAQ.

About the main question:
- concealment sources don't stack;
- my opinion is that other miss chance sources don't overlap, you still get them, and you roll them separately (unless some specific rule of the miss chance source say differently). AFAIK there is no "general" rule for that.
- miss chances from the same kind of source (say two effects that deflect incoming attacks) don't stack, instead they overlap.

Blink ins a good source for how it work:

Blink wrote:

Physical attacks against you have a 50% miss chance, and the Blind-Fight feat doesn't help opponents, since you're ethereal and not merely invisible. If the attack is capable of striking ethereal creatures, the miss chance is only 20% (for concealment).

If the attacker can see invisible creatures, the miss chance is also only 20%. (For an attacker who can both see and strike ethereal creatures, there is no miss chance.) Likewise, your own attacks have a 20% miss chance, since you sometimes go ethereal just as you are about to strike.

So the miss chance is 20% for being invisible part of the time, 20% for being ethereal (if you are capable to see a invisible creature).

50% when both effect stack.

Sovereign Court

Given that concealment isn't even always following the regular rules for concealment (can't use Blur to initiate Stealth) why should things that aren't concealment count as concealment just because they use a similar game mechanic?

Grand Lodge

Ascalaphus wrote:
(can't use Blur to initiate Stealth)

Please show me where I can find that.

Grand Lodge

Pathfinder Adventure, Rulebook Subscriber; Pathfinder Battles Case Subscriber

Under 'Cover and Concealment for Stealth'.

Cover and Concealment for Stealth wrote:
The reason a character usually needs cover or concealment to use Stealth is tied to the fact that characters can’t use Stealth while being observed. A sneaking character needs to avoid all of an opponent’s precise senses in order to use Stealth, and for most creatures, that means vision. Effects such as blur and displacement, which leave a clear visual of the character within the perceiving character’s vision, aren’t sufficient to use Stealth, but a shadowy area or a curtain work nicely, for example. The hide in plain sight class ability allows a creature to use Stealth while being observed and thus avoids this whole situation. A sneaking character can come out of cover or concealment during her turn, as long as she doesn’t end her turn where other characters are directly observing her.

Grand Lodge

TriOmegaZero wrote:

Under 'Cover and Concealment for Stealth'.

Cover and Concealment for Stealth wrote:
The reason a character usually needs cover or concealment to use Stealth is tied to the fact that characters can’t use Stealth while being observed. A sneaking character needs to avoid all of an opponent’s precise senses in order to use Stealth, and for most creatures, that means vision. Effects such as blur and displacement, which leave a clear visual of the character within the perceiving character’s vision, aren’t sufficient to use Stealth, but a shadowy area or a curtain work nicely, for example. The hide in plain sight class ability allows a creature to use Stealth while being observed and thus avoids this whole situation. A sneaking character can come out of cover or concealment during her turn, as long as she doesn’t end her turn where other characters are directly observing her.

Thanks, I'll just tuck that in my pocket for later.

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