Patryn of Elvenshae said:
Taken out of order:
And yet, yours is, as well.
A rapier will not confirm its critical on 15% of "hits." That's crazy talk.
A rapier *threatens* a critical 15% of the time - assuming you don't need more than an 18 to hit. It will confirm its critical 95% of the time - assuming anything but a 1 will hit.
You should be very sure of you math before saying someone elses is pathetic.
The reality is, with one small exception, a weapon that has a crit range of 18-20 *will* get a confirmed critical on 15% of its *hits*.
Yes, some critical threats will confirm, and some will not. *Exactly* like some attacks will hit and some will not. So exactly that they balance out.
Let me try and explain in clearer detail: (I quote myself from another thread)
Coredump said:
Lets say you were playing with a bunch of characters, that all had a crit range of 18-20, and you recorded everytime they hit, and everytime they confirmed criticals for hundreds of attacks each. Yep, you guessed it, their confirmed criticals would be about 15% of their hits. (again, no one is talking about attacks, but hits and criticals)
(For people with a crit range of 20. They will confim critical exactly 5% of the time that they hit, no other details are needed.)
Now, you ask 'why?' (actually, it is usually when people don't ask why, they just assume it is wrong...but lets pretend peolpe ask instead.)
Lets say you have a red die and a blue die (both D20) and you win money if you roll the red die above a 15, and the blue die above a 10.
Does it matter, probablity wise, if you roll the red one first, or the blue one first? No.
Does it matter, probablitly wise, if we change it to blue-15 and red - 10? No.
So, assuming you need a natural 14 to hit the bad guy. I tell you you get a confirmed critical if you roll the first die at 18+, and the second die at 14+. But remember, probability wise, the order doesn't matter.
So, it is the same as saying you get a confirmed critical if you roll the first die 14+, and the second die at 18+.
Now, it should be easier to see that of all your *hits*, you will get a confirmed critical 15% of the time. Because all of the times that you roll a 14+, you will then roll an 18+
(It makes *no* changes to the mechanics/balance/probability/anything of the game if you roll to hit, and then roll to see if you confirm critical.)
Patryn of Elvenshae said:
Which is a faulty way of doing things. Rather, you should calculate expected damage per attack.
But that opens up a number of unneccesary variables. Since the BAB is the same for both, they are both just as likely to hit/miss/confirm. The only difference is how likely they will threaten.
The way SKR (and Staffan) did the calculations is correct. SKR just made the mistake of saying it was slanted. it is (within a few percent) exactly accurate.
From what I can see, your math is correct, but it more complex than needed. Just like those equations where everything factors out to leave a simple answer.
Unfortunately, it also leaves an incorrect assumption.
Now, assuming you hit on anything but a 1 (i.e., Chance of Hit = 95%), then the expected damage for an attack with a Rapier is 14.7 damage per hit - when X is equal to 10.
This both highlights the problem, and how easy the answer is.
The problem develops when people mix the concept of damage per attack, and damage per hit. 14.748 is the damage per *attack*, not damage per hit. On average, each hit will do more than that, you just miss occasionally. (.05% in this case)
Now, you went through some complex and rigorous math to get that answer. Whereas I simply say that the rapier will crit 15% of the time it hits, and therefore will do 15.525 damage per *hit*. (13.5 * 1.15). Now you say a 2 hits, so we will hit 95% of the time. Thus I say average damage per *attack* is (15.525 * .95) or..... 14.748.
That wasn't coincidence. Average damage per *attack* if you need an 11 to hit is (15.525 * .50 ) or 7.7625 per *attack*. Now you try it your way, bet you it matches.
Again, I have yet to decide what I think about them stacking or not. But I just hate to see SKR use such poor math and logic to support his point. He can 'crunch numbers' all he wants, but if he uses the wrong premise, it just doesn't matter.
[NOTE: I have always spoken of a small percent error, or small caveats. The 15% number will be a *little* high because of creatures that need a natural 19 or natural 20 to hit. But since those don't happen very often, it shouldn't change the numbers very much.]