To-hit scaling for powers with base not = 75?

I'm trying to figure out how to slot accuracy for powers with a to-hit base that is different from 75%. Looking at ParagonWiki and Arcanaville's guide regarding to-hit numbers for fighting higher level mobs, I see that if a hero has a base to-hit of 75%, then fighting a mob conning at +3 will have a 48% chance to hit.

Now... how does that scale for a power like Kinetics Transfusion that has a 90% base chance to hit?

I can imagine three ways of calculating this number. Using the formula (1 + (accuracy modifier)) * ((to-hit) - (mob defense)):

Method 1: -27% on your to-hit: 1+(0)*((.75 - .27) - 0) = .48
Method 2: 64% of your base to-hit: 1+(0)*(.75 * .64) - 0) = .48)
Method 3: -36% accuracy penalty: (1 + (-.36)) * (75 - 0) = .48
Method 4: 27% defense against you: (1+0)*((.75) - (.27)) = .48.

Substituting 90% would have a different effect based on the calculation method:
Method 1: (1+0)*((.9 - .27)-0) = .63
Method 2: (1+0)*((.9 * .64)-0) = .576
Method 3: (1-.36)*(.9-0) = .576
Method 4: (1+0)*((.9) - (.27)) = .63

Slotting accuracy causes the numbers to diverge even more. Slotting .25% accuracy (a level 20 IO):
Method 1: (1+.25)*((.9 - .27)-0) = .79
Method 2: (1+.25)*((.9*.64)-0) = .72
Method 3: (1-.11)*(.9-0) = .80
Method 4: (1+.25)*((.9) - (.27)) = .72

Any idea what method is correct? Or is there some entirely different formula?

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First off, powers have base accuracy, no To-Hit. Players have To-Hit, powers have accuracy.

Most powers have an accuracy of 1, or 100%. Some powers go higher, some go lower. The player, against an even-level mob, has 75% base To-Hit. As such, a power with 100% accuracy has the following To-Hit formula:

Final To-Hit = [[Base To-Hit + To-Hit buffs - To-Hit debuffs - Defense] * (Accuracy + Accuracy Buffs - Accuracy Debuffs)]

In this case:

Final To-Hit = 0.75 * 1 = 75%


A power with 90% accuracy will calculate as such:

Final to-Hit = 0.75 * 0.90 = 67.5%



Against a +3 Mob, your ToHit is 48%. The formulas then become:

Final To-Hit = 0.48 * 1 = 48%

and

final ToHit = 0.48 * 0.90 = 43.2%


Slotting for 30% accuracy gives you the following against a +3 Mob:

Final To-Hit = 0.48 * (1 + 0.30) = 62.4%

and

Final To-Hit = 0.48 * (0.90 + 0.30) = 57.6%

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Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted.
~Ralph Waldo Emerson

"I was just the one with the most unsolicited sombrero." - Traegus

75% is the base chance to hit for every calculation. That 90% figure you mentioned is due to Transfusion's base 20% Accuracy Bonus. 75% * 1.2 = 90%. Don't apply the Accuracy Bonus before other modifiers. Just toss it mix with the other factors in the ToHit equation.

You can call if a power has an Accuracy bonus or penalty by looking at the power's Accuracy in the /info window. Accuracy of 1.0 means no bonus or penalty. 1.4 means a 40% Bonus. 0.8 means a -20% penalty.

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You could just use Mid's Hero Designer, which will calculate all that for you and show you the final accuracy.

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[ QUOTE ]
I'm trying to figure out how to slot accuracy for powers with a to-hit base that is different from 75%. Looking at ParagonWiki and Arcanaville's guide regarding to-hit numbers for fighting higher level mobs, I see that if a hero has a base to-hit of 75%, then fighting a mob conning at +3 will have a 48% chance to hit.

Now... how does that scale for a power like Kinetics Transfusion that has a 90% base chance to hit?

[/ QUOTE ]

Powers with increased hit chance actually have higher base Accuracy.

So, it would be...

1.2 (base accuracy of the power) * 0.48 (base hit chance versus +3) = 0.576, 57.60%

Now let's say you slot Transfusion with one +0 Accuracy SO.

[1.2 (base acc) * 1.33 (1 + enhancement value)] * 0.48 = 0.76608, 76.61%

Now let's get crazy with it. Let's say you have Transfusion slotted with 53% Accuracy from IOs and have 27% global +Accuracy.

Oh, heck, let's throw in the Kismet unique's 6% +ToHit, just for fun.

(1.2 * [1 + 0.53 (enhancement value) + 0.27 (global +Acc)]) * [0.48 (base hit chance) + 0.06 (ToHit bonus from IO)] = 1.1664, 116.64%

Rule of thumb: If a power has an increased hit chance, it's an Accuracy increase. ToHit is a player value, Accuracy is a power value.

A power with a base 90% hit chance is actually a power with a base 1.2 Accuracy.

A power with a base 60% hit chance is actually a power with a base 0.90 Accuracy.

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That's perfect... very helpful. Thanks, all!

You can rest easy knowing that many additional criminals will languish in jail now that I have this information (and that my drain on the health care resources of Paragon City will -- hopefully -- abate slightly).

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[ QUOTE ]
You could just use Mid's Hero Designer, which will calculate all that for you and show you the final accuracy.

[/ QUOTE ]Against even-con enemies, at least. Mids' assumes a 75% base tohit, which doesn't hold true when facing enemies higher level than you.

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http://www.fimfiction.net/story/36641/My-Little-Exalt

[ QUOTE ]
[ QUOTE ]
You could just use Mid's Hero Designer, which will calculate all that for you and show you the final accuracy.

[/ QUOTE ]Against even-con enemies, at least. Mids' assumes a 75% base tohit, which doesn't hold true when facing enemies higher level than you.

[/ QUOTE ]

Options -> Configuration -> Exemping & Base Values -> Base ToHit

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