Question: Effect of Accuracy on Critical Strike Chance

Quick question/confirmation!

Referring to this post here: http://www.pathofexile.com/forum/view-thread/11707/filter-account-type/staff/page/10#p748465

If my understanding is OK, if I have 95% critical strike chance and 90% accuracy, ignoring monster evasion, on any given hit (meaning I'm assuming you land the hit) there is a 15% chance that I will not crit (or 85% chance I will crit).

My reasoning is like this, there is a 5% normal chance that I won't crit, but because of the second roll that Mark_GGG talks about, it looks like even if I do initially roll crit, this has to pass another test whereby if a random roll from 1-100 lands above your "chance to hit" (= to accuracy when evasion is ingored), the crit is negated. So there are two ways not to crit: either I fail the first normal roll (5% chance) or I fail the second roll/accuracy test (10% chance).

5% + 10% = 15% not to crit (= 85% chance to crit)

Am I correct?

afaik that is correct.

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JakeAlmighty wrote:

afaik that is correct.

thank you good sir

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KiPad wrote:

5% + 10% = 15% not to crit (= 85% chance to crit)

Am I correct?

The math is wrong, but your results aren't far off.

Your chance to crit is 95%, but your accuracy only lets 90% of them through. Result:

.95 * .9 = .855 or 85.5% chance to crit on each hit

However, only 90% of your attacks will hit. Result:

.855 * .9 = .77 or 77% chance to crit on each attack

Someone correct me if I'm wrong, but I think your overall crit chance would be 76.95% since accuracy check is done twice. 0.9 * 0.9 * 0.95

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RogueMage wrote:

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KiPad wrote:

5% + 10% = 15% not to crit (= 85% chance to crit)

Am I correct?

The math is wrong, but your results aren't far off.

Your chance to crit is 95%, but your accuracy only lets 90% of them through. Result:

.95 * .9 = .855 or 85.5% chance to crit on each hit

However, only 90% of your attacks will hit. Result:

.855 * .9 = .77 or 77% chance to crit on each attack

"

kolton wrote:

Someone correct me if I'm wrong, but I think your overall crit chance would be 76.95% since accuracy check is done twice. 0.9 * 0.9 * 0.95

You guys are totally right, it's why I specified "on any given hit" :P Thank you for reconfirming though, I really appreciate it ^^ Just wanted to make sure the basis of some of my theory-crafting wasn't totally off haha

There is still a bug in all this calculations.

Assuming you have a listed accuracy of 90% against a specified monster and a listed 95% chance to crit.
You attack, chance to hit is rolled -> 90% hit, 10% miss.
In case you hit, cit is rolled. However, the crit is then rolled again against evasion. If it fails, the attack is downgraded to a normal hit.
Therefore chance to hit with a crit = 0.9*0.9*0.95 = 0.77 (approx).

This makes chance to hit very important for attack based crit builds.

Edit: Oh wait, didn't read enough of this thread, was already mentioned - sorry.
At least provided link to source of calculations tough.