[Rogue] Backstab damage calculation
 

The backstab/sinister strike damage calculation in both Rogue-DPS and Rogue-Gear spreadsheet
seem to be wrong for the current live and PTR servers.

What started this was the observation that the tooltip information for backstab did not match
the conventional wisdom as shown in the sheets.
With a 15/41/5 combat dagger build on live the tooltip for backstab is:

195% weapon dmg +255

and on PTR with added aggression:

204% weapon dmg +255

Now the spreadsheets calculate:

150*(1+opportunity)*(1+suprise attacks)*(1+aggression)

For live this comes out to 198% (opportunity and surpise attacks) and for PTR to 208%

So is this only a fluke in the frontend or a real issue?
I went to respec a couple of times on the PTR observing for every point spent the backstab tooltip.
From that it looks like the backstab multiplier is computed as:

150% *(1+opportunity+surprise+aggression)

That matches the BS tooltip for live and PTR in all combinations of spending points.

Now does the server calculate the same?
Seems so!
I got me a starting dagger (1-2 dmg 1.6 speed) and teste with some mobs on live and PTR.
Attack sequence was:
Cheap Shot, BS, Kick and of course the autoattacks.
Kick to get a guess of the armor reduction.

Spec was 15/41/5, 1735 AP no "on proc AP" trinkets.
First subject was an undead mage on hellfire peninsula:

Kick showed 85 dmg, backstab 578

From the kick dmg we can compute the armorreduction.
Since I dont know how Blizz rounds dmg numbers, I computed an upper and lower bound for dmg reduction:

(85-0.5)/110 = .768182 (to account for proper roundig up)
(85+0.99999)/110 = 0.78181 (to account for truncation).

(Sidenote: I purposly did not account for murder talent and wordlbuff in this computation. They will cancle out later anyway)
Now for the damage calculations
The observed dmg of 578 fits nicely in the second dmg range.

My conclusion: WoW really computes the backstab damge different than the current sheets do.
I dont think that is a stealth nerf in one of the last versions. Rather I think the formulas
were not correctly tested when rogue theocrafting started.

What seems to be necessary now is to reestablish the order of application of different talents/set boni; are they really multiplikativ or rather additive?

Note on armor reduction values obtained via 'kick' method:
When this was done, did everyone took into account "Murder", "Worldbuff" and possibly other global dmg enhancinge buffs?

While testing with different mobs (unded/human) it looks like at least "Murder" and the worldbuffs still factor in multiplicative.

Snippet from combatlog

Interesting find. I'll go and do some tests myself and see if I can post em here.

PTR Seems to be moving slowly, So I'll just do some on Live.

Okey, Done.



Shows 1332 Ap, 123 hit, ALMOST 20% armor reduction, Miner/eng = no +weapondamage on ring. No trinkets, no meta gem (Meh w/e) Also Deequiped items with armor reduce.

So let's do the values.

(1332/14)*1,7 + 1,5 = 163,243

WoW Values (163,243*1,5+255) * 1,3 = 649,824 With armor
649,824 * 0,8 = 519,859. Taking the small armor difference from 20, and truncations ~520 is very close to 521.

Take the sheets values, (163,243*1,5+255) * 1,2 * 1,1 = 659,821 With armor 659,821 * 0,8 = 527,857. Not as close. I think we can conclude that the sheets need some tuning =).

Thanks krystah for your time testing.

Maybe helpful:
http://elitistjerks.com/f31/t16940-r..._a/#post506126
http://elitistjerks.com/f31/t14304-r...40/#post518461

We now have 3 people who have tested this and come to the same conclusion...
Truth be told, I tested this when Surprise Attacks was first added and found it to be additive with Opportunity. Although, when the 41 point talents first got added prior to the expansion, the +255 was not multiplied (it is now).

Mehh:/
Missed that.
Truth is lastly I did not follow the sheet threads because they were derailing IMO :(

Not a problem at all. I'm glad you put up this post with such a well-documented display. Further documentation is always good.