Just wanted to share some basic data and break down for Prismatic Spray. (This data looks at all probabilities of rolling 1-7, and all potential double rolls for rolling an 8)
Average Damage per target = 28.125
Chance of Blindness + Banish = 18.36%
Chance of Restrained + Petrified = 18.36%
In comparison to 7th level Chain Lightning, you need to hit 8 targets to equal the damage. The bonus effects will likely add value so there may be a trade off there as well.
Chain Lightning affects a maximum of 4 targets, average 44 damage each (if all saves fail)
Prismatic Spray affects all creatures in a 60 ft cone. Against 8 targets you are quite likely to roll at least one 8, so that improves the potential damage further.
You might need to hit 8 targets to equal the damage; but even more than 4 targets being hit will spread the damage around more enemies; and at 15th level the 44 damage from chain lightning isn't going to make a big dent in any enemy's HP.
That damage breakdown doesn’t seem to take into account the chance to not roll damage at all.
it’s roughly 28 damage IF the 1d8 falls on a damage effect. This does seem to take into account the chance for saving throw failure which is good.
the chances to roll non damage takes away from the chance to deal damage at all vs a target. The double roll after an initial 8 can also be one or even two of those status effects dealing non damage.
Chain Lightning affects a maximum of 4 targets, average 44 damage each (if all saves fail)
Prismatic Spray affects all creatures in a 60 ft cone. Against 8 targets you are quite likely to roll at least one 8, so that improves the potential damage further.
You might need to hit 8 targets to equal the damage; but even more than 4 targets being hit will spread the damage around more enemies; and at 15th level the 44 damage from chain lightning isn't going to make a big dent in any enemy's HP.
I upcasted Chain Lightning to level 7, to compare properly. The potential damage average takes into account potential of rolling 8 as well.
Neither spell would be used against bosses - hitting 5 targets at an average of 45 is 225 total damage, which could be very useful against some foot soldiers.
That damage breakdown doesn’t seem to take into account the chance to not roll damage at all.
it’s roughly 28 damage IF the 1d8 falls on a damage effect. This does seem to take into account the chance for saving throw failure which is good.
the chances to roll non damage takes away from the chance to deal damage at all vs a target. The double roll after an initial 8 can also be one or even two of those status effects dealing non damage.
It absolutely takes into account no damage at all and also double damage (depending on your rolls after rolling an 8). The %chance of the 6 and 7 rolls is also calculated based on all probabilities.
That damage breakdown doesn’t seem to take into account the chance to not roll damage at all.
it’s roughly 28 damage IF the 1d8 falls on a damage effect. This does seem to take into account the chance for saving throw failure which is good.
the chances to roll non damage takes away from the chance to deal damage at all vs a target. The double roll after an initial 8 can also be one or even two of those status effects dealing non damage.
It absolutely takes into account no damage at all and also double damage (depending on your rolls after rolling an 8). The %chance of the 6 and 7 rolls is also calculated based on all probabilities.
Well was I wrong about the save DC? We’re you using a 60% of success? The numbers still seem high to me.
That damage breakdown doesn’t seem to take into account the chance to not roll damage at all.
it’s roughly 28 damage IF the 1d8 falls on a damage effect. This does seem to take into account the chance for saving throw failure which is good.
the chances to roll non damage takes away from the chance to deal damage at all vs a target. The double roll after an initial 8 can also be one or even two of those status effects dealing non damage.
It absolutely takes into account no damage at all and also double damage (depending on your rolls after rolling an 8). The %chance of the 6 and 7 rolls is also calculated based on all probabilities.
Well was I wrong about the save DC? We’re you using a 60% of success? The numbers still seem high to me.
Good point - I didn’t make any assumptions about save percentages. This is raw average damage with no save made. For simplicity sake I didn’t include a save percentage at all in comparing Chain Lightning.
I think some of the power of chain lightning comes from its targeting options. It feels like an older version of steel wind strike to me in that it’s kind of like an AOE that you can use safely around allies.
Chain lightning can do something niche that steel wind strike and prismatic spray can’t do, and that’s be used in a way to bounce around corners.
chain lightning can be used to target an object, such as a door or wall. Only the first target is required to be seen by the caster. So a caster can target an object 150ft away that has a clear path and then bounce the other bolts 30ft away to hit other targets kind of like a ricochet effect. Your damage takes a hit, but it gives you options while keeping your party safe from you’re own fire. You could bounce it off a ceiling if you fall in a pit. You can bounce it off low CR fodder to target invisible BBEGs. You can step around a corner to prevent yourself from being counterspelled and target the ground itself.
objects usually aren’t immune to lightning damage and also auto fail dexterity saves, so you can probably blow through some walls or doors and target creatures on the other side.
Just wanted to share some basic data and break down for Prismatic Spray. (This data looks at all probabilities of rolling 1-7, and all potential double rolls for rolling an 8)
Average Damage per target = 28.125
Chance of Blindness + Banish = 18.36%
Chance of Restrained + Petrified = 18.36%
In comparison to 7th level Chain Lightning, you need to hit 8 targets to equal the damage. The bonus effects will likely add value so there may be a trade off there as well.
You can't ignore the need to make it past saves for these numbers to have any meaning. I saw 60% being thrown around up above, which sounds arbitrary - the DMG recommends hitting with odds 65% at all levels except 9, where it recommends 70%, but it has no coherent recommendation at all for likelihood of penetrating saves. I'll do the math with 60%, since we have no choice but to be arbitrary with save penetration, and saves being slightly less accurate than attacks makes some sense, as save bonuses can easily exceed the equivalent of AC 20 (e.g. a +2 to hit attack against AC 20 hits 15% of the time, but a DC 10 spell against someone with +11 to the save hits 5% of the time). To be explicitly clear, I will assume the target has the same chance on Dexterity, Wisdom, and Constitution saves.
Chain Lightning: 35.9 per target, max 4 targets, so 35.9 to 143.6 damage. 179.5 total if upcast against a fifth target.
Prismatic Spray: A damaging hit deals 27.9 damage. A restraining hit petrifies with odds 0.3456. A blinding hit banishes with odds 0.36.
When the spray hits you, it's:
X = 5/8(damage) + 1/8(petrify) + 1/8(banish) + Y/8
I'm assuming petrifies and banishes stack with themselves - if you're hit with two restraining sprays or two blinding sprays, you have to resolve both mechanics independently.
Petrify: 0.3456/8 + (12/49*0.3456+1/49*0.5904)/8 = 5.52% per target
Banish: As above with the banish odds = 5.76% per target
Net odds of takedown are messier - i.e. only petrify + only banish + both - but it's 10.98%.
Petrify and Banish deal more "damage" the more health the target has, since they eliminate the target all at once - you can simulate them as damaging effects by multiplying their chances by the target's hit points. You can do the reverse by dividing a damaging effect's damage by the target's health pool. To reconcile the numbers, I'll assume CR 13 targets with average hit points, so 258.
Chain Lightning: 13.92% per target (maximum targets with an L7 slot: 5).
Prismatic Spray: 19.67% per target (maximum targets depends on whether your DM uses a grid, and if they do, whether they use the DMG rules for grids or the optional Xanathar's rule for snapping a template to the grid, but either way it's quite large).
A lot of assumptions were made here, but I hope I was clear about them.
Just wanted to share some basic data and break down for Prismatic Spray. (This data looks at all probabilities of rolling 1-7, and all potential double rolls for rolling an 8)
Average Damage per target = 28.125
Chance of Blindness + Banish = 18.36%
Chance of Restrained + Petrified = 18.36%
In comparison to 7th level Chain Lightning, you need to hit 8 targets to equal the damage. The bonus effects will likely add value so there may be a trade off there as well.
You can't ignore the need to make it past saves for these numbers to have any meaning. I saw 60% being thrown around up above, which sounds arbitrary - the DMG recommends hitting with odds 65% at all levels except 9, where it recommends 70%, but it has no coherent recommendation at all for likelihood of penetrating saves. I'll do the math with 60%, since we have no choice but to be arbitrary with save penetration, and saves being slightly less accurate than attacks makes some sense, as save bonuses can easily exceed the equivalent of AC 20 (e.g. a +2 to hit attack against AC 20 hits 15% of the time, but a DC 10 spell against someone with +11 to the save hits 5% of the time). To be explicitly clear, I will assume the target has the same chance on Dexterity, Wisdom, and Constitution saves.
Chain Lightning: 35.9 per target, max 4 targets, so 35.9 to 143.6 damage. 179.5 total if upcast against a fifth target.
Prismatic Spray: A damaging hit deals 27.9 damage. A restraining hit petrifies with odds 0.3456. A blinding hit banishes with odds 0.36.
When the spray hits you, it's:
X = 5/8(damage) + 1/8(petrify) + 1/8(banish) + Y/8
I'm assuming petrifies and banishes stack with themselves - if you're hit with two restraining sprays or two blinding sprays, you have to resolve both mechanics independently.
Petrify: 0.3456/8 + (12/49*0.3456+1/49*0.5904)/8 = 5.52% per target
Banish: As above with the banish odds = 5.76% per target
Net odds of takedown are messier - i.e. only petrify + only banish + both - but it's 10.98%.
Petrify and Banish deal more "damage" the more health the target has, since they eliminate the target all at once - you can simulate them as damaging effects by multiplying their chances by the target's hit points. You can do the reverse by dividing a damaging effect's damage by the target's health pool. To reconcile the numbers, I'll assume CR 13 targets with average hit points, so 258.
Chain Lightning: 13.92% per target (maximum targets with an L7 slot: 5).
Prismatic Spray: 19.67% per target (maximum targets depends on whether your DM uses a grid, and if they do, whether they use the DMG rules for grids or the optional Xanathar's rule for snapping a template to the grid, but either way it's quite large).
A lot of assumptions were made here, but I hope I was clear about them.
I can absolutely ignore the save percentages for the numbers to have meaning. Both Chain Lightning and Prismatic Spray have the same Save and therefore can be compared directly without considering the bonus effects.
Especially when you say 60% is arbitrary - because any number taken will be arbitrary and completely dependent on the game played and magic items available. Stats about the average game won’t give you any more reasonable data if the actual output isn’t representative of any game played. Variables should be removed from a statistic, not added.
For example, these variables you’ve added have begged the following questions:
1) Your mention of saves percentages is wrong:
”but a DC 10 spell against someone with +11 to the save hits 5% of the time”
Saves do not have critical success and fail metrics. A DC 10 spell will never work on someone with +11 to the save.
2) Banishing (or Plane Shifting more practically) someone can not be assumed to do more “damage”. In fact, for many creatures you fight at the levels of Prismatic, there is a chance they can also Plane Shift back, or are plain immune to petrify. This is why I didn’t include this in my numbers either.
3) Your damage numbers for Chain Lightning and Prismatic Spray don’t seem to make any sense - using arbitrary 60% success rates means CL has a 40% chance of doing 22.5 damage and a 60% chance of doing 45 damage on average which means it does 36, not 35.9.
Prismatic with a 60% chance of success does 60% of 35 added to 40% of 17.5, 21+7 = 28, not 27.9.
The chance of rolling damage when rolling 2d8 is actually 45 out of the 49 chances. 25 rolls of 2d8 will be double damage (as I think your formula calculates), but damage is also incurred when you roll a single petrify and/or banish as well. So that adds another 20 rolls of 2d8 where you get single damage again from the Prismatic Spray.
5) During the time they are petrifying, they are restrained and essentially doing no damage if they are melee creatures. How are you capturing that statistic?
6) What is the permutation/combination formulae you’re using for calculating petrification and banishment rates?
Just wanted to share some basic data and break down for Prismatic Spray. (This data looks at all probabilities of rolling 1-7, and all potential double rolls for rolling an 8)
Average Damage per target = 28.125
Chance of Blindness + Banish = 18.36%
Chance of Restrained + Petrified = 18.36%
In comparison to 7th level Chain Lightning, you need to hit 8 targets to equal the damage. The bonus effects will likely add value so there may be a trade off there as well.
Chain Lightning affects a maximum of 4 targets, average 44 damage each (if all saves fail)
Prismatic Spray affects all creatures in a 60 ft cone. Against 8 targets you are quite likely to roll at least one 8, so that improves the potential damage further.
You might need to hit 8 targets to equal the damage; but even more than 4 targets being hit will spread the damage around more enemies; and at 15th level the 44 damage from chain lightning isn't going to make a big dent in any enemy's HP.
That damage breakdown doesn’t seem to take into account the chance to not roll damage at all.
it’s roughly 28 damage IF the 1d8 falls on a damage effect. This does seem to take into account the chance for saving throw failure which is good.
the chances to roll non damage takes away from the chance to deal damage at all vs a target. The double roll after an initial 8 can also be one or even two of those status effects dealing non damage.
I upcasted Chain Lightning to level 7, to compare properly. The potential damage average takes into account potential of rolling 8 as well.
Neither spell would be used against bosses - hitting 5 targets at an average of 45 is 225 total damage, which could be very useful against some foot soldiers.
It absolutely takes into account no damage at all and also double damage (depending on your rolls after rolling an 8). The %chance of the 6 and 7 rolls is also calculated based on all probabilities.
Well was I wrong about the save DC? We’re you using a 60% of success? The numbers still seem high to me.
Good point - I didn’t make any assumptions about save percentages. This is raw average damage with no save made. For simplicity sake I didn’t include a save percentage at all in comparing Chain Lightning.
I think some of the power of chain lightning comes from its targeting options. It feels like an older version of steel wind strike to me in that it’s kind of like an AOE that you can use safely around allies.
Chain lightning can do something niche that steel wind strike and prismatic spray can’t do, and that’s be used in a way to bounce around corners.
chain lightning can be used to target an object, such as a door or wall. Only the first target is required to be seen by the caster. So a caster can target an object 150ft away that has a clear path and then bounce the other bolts 30ft away to hit other targets kind of like a ricochet effect. Your damage takes a hit, but it gives you options while keeping your party safe from you’re own fire. You could bounce it off a ceiling if you fall in a pit. You can bounce it off low CR fodder to target invisible BBEGs. You can step around a corner to prevent yourself from being counterspelled and target the ground itself.
objects usually aren’t immune to lightning damage and also auto fail dexterity saves, so you can probably blow through some walls or doors and target creatures on the other side.
You can't ignore the need to make it past saves for these numbers to have any meaning. I saw 60% being thrown around up above, which sounds arbitrary - the DMG recommends hitting with odds 65% at all levels except 9, where it recommends 70%, but it has no coherent recommendation at all for likelihood of penetrating saves. I'll do the math with 60%, since we have no choice but to be arbitrary with save penetration, and saves being slightly less accurate than attacks makes some sense, as save bonuses can easily exceed the equivalent of AC 20 (e.g. a +2 to hit attack against AC 20 hits 15% of the time, but a DC 10 spell against someone with +11 to the save hits 5% of the time). To be explicitly clear, I will assume the target has the same chance on Dexterity, Wisdom, and Constitution saves.
Chain Lightning: 35.9 per target, max 4 targets, so 35.9 to 143.6 damage. 179.5 total if upcast against a fifth target.
Prismatic Spray: A damaging hit deals 27.9 damage. A restraining hit petrifies with odds 0.3456. A blinding hit banishes with odds 0.36.
When the spray hits you, it's:
X = 5/8(damage) + 1/8(petrify) + 1/8(banish) + Y/8
I'm assuming petrifies and banishes stack with themselves - if you're hit with two restraining sprays or two blinding sprays, you have to resolve both mechanics independently.
Y = 2*5/7*damage + 2*1/7*6/7*petrify + 2*1/7*6/7*banish + 1/49*double-petrify + 1/49*double-banish
double-petrify = 0.5718, double-banish = 0.5904
So total:
Damage: 27.9*(5/8+1/8*2*5/7) = 22.4196 per target
Petrify: 0.3456/8 + (12/49*0.3456+1/49*0.5904)/8 = 5.52% per target
Banish: As above with the banish odds = 5.76% per target
Net odds of takedown are messier - i.e. only petrify + only banish + both - but it's 10.98%.
Petrify and Banish deal more "damage" the more health the target has, since they eliminate the target all at once - you can simulate them as damaging effects by multiplying their chances by the target's hit points. You can do the reverse by dividing a damaging effect's damage by the target's health pool. To reconcile the numbers, I'll assume CR 13 targets with average hit points, so 258.
Chain Lightning: 13.92% per target (maximum targets with an L7 slot: 5).
Prismatic Spray: 19.67% per target (maximum targets depends on whether your DM uses a grid, and if they do, whether they use the DMG rules for grids or the optional Xanathar's rule for snapping a template to the grid, but either way it's quite large).
A lot of assumptions were made here, but I hope I was clear about them.
I can absolutely ignore the save percentages for the numbers to have meaning. Both Chain Lightning and Prismatic Spray have the same Save and therefore can be compared directly without considering the bonus effects.
Especially when you say 60% is arbitrary - because any number taken will be arbitrary and completely dependent on the game played and magic items available. Stats about the average game won’t give you any more reasonable data if the actual output isn’t representative of any game played. Variables should be removed from a statistic, not added.
For example, these variables you’ve added have begged the following questions:
1) Your mention of saves percentages is wrong:
”but a DC 10 spell against someone with +11 to the save hits 5% of the time”
Saves do not have critical success and fail metrics. A DC 10 spell will never work on someone with +11 to the save.
2) Banishing (or Plane Shifting more practically) someone can not be assumed to do more “damage”. In fact, for many creatures you fight at the levels of Prismatic, there is a chance they can also Plane Shift back, or are plain immune to petrify. This is why I didn’t include this in my numbers either.
3) Your damage numbers for Chain Lightning and Prismatic Spray don’t seem to make any sense - using arbitrary 60% success rates means CL has a 40% chance of doing 22.5 damage and a 60% chance of doing 45 damage on average which means it does 36, not 35.9.
Prismatic with a 60% chance of success does 60% of 35 added to 40% of 17.5, 21+7 = 28, not 27.9.
Why are these adjusted downwards 0.1?
4) But then your probabilities look off too...
”Y = 2*5/7*damage + 2*1/7*6/7*petrify + 2*1/7*6/7*banish + 1/49*double-petrify + 1/49*double-banish“
The chance of rolling damage when rolling 2d8 is actually 45 out of the 49 chances. 25 rolls of 2d8 will be double damage (as I think your formula calculates), but damage is also incurred when you roll a single petrify and/or banish as well. So that adds another 20 rolls of 2d8 where you get single damage again from the Prismatic Spray.
5) During the time they are petrifying, they are restrained and essentially doing no damage if they are melee creatures. How are you capturing that statistic?
6) What is the permutation/combination formulae you’re using for calculating petrification and banishment rates?