SBV vs Stamina - Theorycrafting

[Georgie]

Has anyone here ever done any theorycrafting (or knows of a link to someone else that has) about the quantifiable differences between SBV and stamina? I'm looking at this purely from a tank survivability issue at this point. Obviously SBV has bonuses for threat and damage but those differences are determined by the individual tastes of the tank and they mean nothing once you die in a fight. So, how much SBV does it take to equal 1 point of stamina, given the same armor?

Me and several other tanks in my guild have been talking about this since the changes to strength and SBV came into effect in 3.0.2. My intuition tells me to stack SBV as high as possible without letting unbuffed HP go below a defined point (say, 16k for most of the T6 content we currently do). The obvious problem with that is that it's easy to give up 500 HP for the first additional 300 SBV but should I really give up an additional 300 HP after that for a measly 50 SBV, for instance? It's obvious to me that at some point raw stamina outweighs raw SBV and I was hoping someone had already worked it out so I wouldn't have to.

[Yarock]

That's not unlike comparing mitigation to effective health. They don't translate precisely. I believe effective health is king until you are nearly certain a streak of failed mitigation will be healable - then SBV/mitigation would be king. Even if you have 33% block rating the best you could hope for is 50% of attacks being blocked using shield block every 40 seconds. Given the average gear level and nerfed bosses on live it would be hard to go wrong stacking SBV right now - but once we hit 80 hopefully things will be more difficult requiring effective health.

[Kazeyonoma]

SBV is calculated as part of the EH formula because it is a psuedo reliable damage mitigation stat so trying to calculate them separately is kinda... weird.

[mero12513]

I'm just gonna trow some numbers out for people to find problems with and correct for me. I'll make a bunch of crazy assumptions for very specific cases, and then someone smarter than me can make the "General Theory of Shield Block Value".

I will assume that you have 0% true avoidance, because stam vs SBV means nothing if you dodge.
I will assume all damage is physical.
I will assume you use a talented shield block on cooldown.
I will assume that you will never block an entire hit.
I will assume that shield block actually doubles your entire block value (it doesn't).
I will assume that critical block literally doubles the amount you would have normally blocked (it may or may not, I have not seen testing).

Given a chance to block Cb, we expect, over infinite time to block Cb% of attacks (without shield block). With shield block up, you will block 100% of attacks. In the 50 second Shield Block rotation, 40 seconds (80%) is at block chance Cb. 10 are at 100% block chance, with double block value (sorta). Remember, also, that we have 30% chance to block for DOUBLE what we already do.

Given extra Block value from strength (.5 BV / Str), we get the following amount of damage reduction directly from a given value of Strength (S):

Dr = ((.5)S * (.8)Cb% + 2(.5)S * (.2)100%) <- no critical blocks
Dr = (.4 * Cb% + .2)S
Dr = .7 * (.4 * Cb% + .2)S + .6 *(.4 * Cb% + .2)S <- with critical blocks
Dr = ((.28)Cb% + .14)S + ((.24)Cb% + .12)S
Dr = ((.52)Cb% + .26)S * 1.3 <- taking into account 30% extra BV

If the above math is correct (which it probably isn't), the amount of damage you reduce on an average physical hit due to the block you gain from strength is equal to approximately half of your block chance times the strength gained plus one quarter of the strength gained.

--Edit-- I forgot about Shield Mastery. Multiply everything by 1.3.

[Mordigen]

Situational awareness. I like to use SBV gear for trash or anything that I know I can take a little beating and still get healed and EH if I want to be safe or know there could be a point where my life might get low. Most of the 5 mans and that now you will be fine wearing the SBV gear now worries, but I do hope it gets back to progression gearing once we get to 80, which I am sure it will.

[Andenthal]

My intuition tells me to stack SBV as high as possible without letting unbuffed HP go below a defined point

I think you've all ready got the idea. Once you reach the EH minimum for a fight, you can start stacking avoidance, threat, or both depending on need.

For me, it's like Defense and its relation to uncrittable. If you still have a chance to be crit, Defense is the best bang for the buck compared to any other stat for making you live longer. After that mark Defense is nice, but other stats provide better returns for survivability if you are min/maxing (or they used to at least)

If you are below the EH minimum, each point of HP or armor will allow you to survive the fight, moreso than any other ability. Once you reach the EH minimum, Stamina is still nice, but you generally get better returns investing in other stats to prolong your life.

I guess what I'm saying is that there are a ton of variables you need to take into consideration. Yes, while still level 70 most tanks are likely overgeared for all content. But at level 80, we will all need to take this into consideration. As Mero hinted at, any fight with magic damage automatically devalue SBV a little because it provides no mitigation fro magic attacks.

[Shadevarr]

Did some testing with one of our raid healers that is able to give me accurate feedback on healing me in addition to recount.

Max EH gear: 17k health, 18.5k armor 522 sbv
Max SBV gear: 15.6k health 17.5k armor 1109 sbv

Feedback was that the 2nd gear set was "a joke to keep you up"

Only time I would use EH anymore is on bosses that do huge DoTs.

[Navlelo]

1k armor difference vs 600 BV is a rather clear choice imo :P

[Glomgore]

I have though about this much myself, and noticed the same thing. I keep around 16, 16.5khp unbuffed, hitting 20k raid buffed and flasked/fooded, and I've started swapping in hybrid gems for my 12 stam ones, and prefing gear with SBV over dodge.

My healers love me, especially druid healers. I had a druid healer fall asleep on me in heroic MGT last night she was so bored.

THe world is moving toward block, and those that figure it out will be king ^_^

[Shagh]

I am reading all this talk of increasing SBV but as a newly progressing casual tank I cannot easily see how to apply this to my gear.

I am only 14K unbuffed in my Tanking gear. I use Tankpoints to guide me although I am aware it is not the complete answer.

Would like to see more theory on this but I am guessing Wrath is too close to bother as we will all be moving through gear and content new to us.

[Lionheart]

From the appearance of the way that SBV and Mitigation work togeather it seem that stacking one in the absence of the other is detrimental and there is likely a medium that needs to be met except in extreams. Having extremes in mitigation lowers the effectivness of SBV as does having extreme SBV such as being able to fully mitigate boss attacks(unlikly past kara).

From observations it appears that mitigation is taken into account first when figuring out how much an attack is going to land on you for making this the primary form of damage mitigation increasing the value of shield block value's effectiveness. SO by having 65% mitigation your decreasing the amount the attack would hit for by 65% and then if your also able to block the attack your taking an additional amount away from the unmitigated portion of the attack. Therefore the higher the combined SBV/Mitigation/Block% would be the information from the player that would be needed to figure out how much value SBV and stam are related in terms of effective health. Somewhere there is also a need to know how much the boss maximum hit or combination is for and the attack rate of the boss to determine the balance. In the end the safest way to deal with a boss is stacking mitigation/stam for maximum effective health however as a side effect this will also put the greatest strain on healers ablity to heal you as in the end you will be mitigating less overall damage then you would had you properly balanced mitigation/sbv/block%/stam so to minimize the damage however this comes with an increased risk that you will get that unlucky streak where you are taking higher then normal damage and your healers will be cought off guard as they tend to get lazy when the tank is taking far less damage then you would in a Max Effective health set.

[Tenraiel]

I made a spreadsheet since I've been wondering this stuff myself. Take a look, it may be helpful, but I'd also LOVE some feedback from the more experienced with this stuff.

RapidShare: Easy Filehosting

<edit> It's made for warriors as it assumes usage of shield block on cd and critical block. I could make it into a pally friendly version pretty easily though if anyone wants

[Kazeyonoma]

but... you don't spam Shield Block anymore... You save it for a mini-shield wall, spamming it constantly is probably more detrimental to your survivability than saving it for that OH CRAP moment.

[Shagh]

Yeah, I agree on saving Shield Block.

I tend to use it when I think the healer is under pressure and on all boss fights.

I like the idea of measuring the effectiveness of differents stats and can understand how say having massive amounts of stamina may not be as good as dropping some for more SBV.

This is one area I think that will require some work to make it easier for the non-mathematicians to understand.

[Tenraiel]

Well, personally, I still spam it. <insert standard argument here> I made it assuming spam of shield block since that's what I'm doing. I could remove that assumption pretty easily though.

[Kazeyonoma]

I'd remove it since the advice of Ciderhelm and general convention is to treat it more of a Oh Crap! button than a constant press. 40 seconds without it can mean death.

Just have it base the value of SBV by calculating your SBR.

[Ranx]

tbh i agree with tenrail, we have both last stand and shield wall, so saving shield block is not needed imo, especaily not with bosses being as nautered as they r atm, maybe it is needed in LK but tbh i really doubt it, maybe on some gimick fights. But general i think it is best to be popping it as soon as the cd is up.

[Yarock]

I don't think of SBV as a survival stat - if I'm having trouble staying alive I would go for stamina/armor or even dodge. SBV is a threat or perhaps more importantly a DPS stat. Through creative gearing (14k health 20k armor, 750SBV, well over 1700AP unbuffed, very little avoidance - lots of S4 PvP gear) I've been able to see 1400dps sustained in a shattered halls run and over 1000dps (seeing over 4000tps) on single target boss fights - the #2 dps was over 1800 and I beat them in damage by a good bit.

[Tenraiel]

aye, we downed Illidan for the first time this Monday, I didn't have Deflection or Anticipation and it still went very well. At this point in the game I see NO reason not to use it on cd. Wotlk may change that, but we have Last Stand and Shield Wall already. (I scored t6 chest! and I'm pumped btw!)

[Kazeyonoma]

So if you're using it on CD, you're using it for the threat component and not the survivability aspect of it. I'd argue then that you aren't testing what the OP had asked for.