Effective Health Theory

[Ciderhelm]

Notice - This guide needs to be updated. There are clearly encounters where Avoidance is superior to Effective Health, such as Prince in Karazhan. Will have an update ASAP. - Mar 28 '08

Let's establish what Effective Health and Effective Stamina are. This is basically a measurement of how much raw damage a creature has to deal to kill you. It is a measurement of Armor and it's relation to Stamina.

What many tanks do not understand is just how much damage a creature is dealing to them. I didn't realize it until I studied Patchwerk -- who dealt 22,000 to 29,000 raw damage to our tanks with every Hateful Strike.

Effective Health is the measurement of how much breathing room your healers have to keep you alive assuming all other factors fail -- assuming you do not avoid or block attacks or have a mana shield active. Effective Health is important for tanking heavy hitting creatures because of Murphy's Law -- if you can have long strings of not Dodging an attack, it will definitely happen. Raid tanking, ultimately, is about stability.

Life Per Stamina (LPS) & Effective Life Per Health (ELPH)

  AC                 Mitigation         LPS           ELPH

0 ___________________   0.00% _____    10 : 1 ____  1.00 : 1
10,000 ______________  48.64% _____  19.4 : 1 ____  1.94 : 1
12,000 ______________  53.20% _____  21.3 : 1 ____  2.13 : 1
13,000 ______________  55.18% _____  22.3 : 1 ____  2.23 : 1
14,000 ______________  57.01% _____  23.2 : 1 ____  2.32 : 1
15,000 ______________  58.69% _____  24.2 : 1 ____  2.42 : 1
16,000 ______________  60.25% _____  25.1 : 1 ____  2.51 : 1
17,000 ______________  61.69% _____  26.1 : 1 ____  2.61 : 1
20,000 ______________  65.45% _____  28.9 : 1 ____  2.89 : 1
25,000 ______________  70.31% _____  33.6 : 1 ____  3.36 : 1

The equation to determine Life Per Stamina is (Special thanks to Ilmare):

1 / (1 - Mitigation)

Mitigation is determined through this equation (Special thanks to Satrina):

                          Armor
Mitigation (70) =   -----------------
                     Armor + 10557.5



                          Armor
Mitigation (73) =   -----------------
                      Armor + 11960

Effective Life Per Health is determined simply by dividing the Stamina numbers by 10.


Special Note: Please keep in mind that every 1,000 Armor produces precisely the same increase in Effective Life that the last 1,000 Armor did. Satrina has covered this in-depth, but it can never hurt to say it again -- Mitigation is subject to diminishing returns but Armor is not. Armor provides a linear increase in life expectancy. Stamina scales with Armor.

Link to Satrina's information: The Mathematics of Armour and Diminishing Returns




Examples
The first hypothetical is for a tank who has chosen primarily to focus on Stamina and Armor over Avoidance and Defense. The following are reasonable attributes for this Warrior, assuming he has been through Karazhan but not further:
14,000 Armor
13,000 Health

If we run with the above Effective Life Per Health ratio, this is our end result:

13,000 * 2.32 = 30,160 Effective Life


Let's take the standard number of people who tend to itemize Avoidance and Defense equally, or sometimes in greater standing than Stamina and Armor:
12,000 Armor
12,000 Health

Running the same equation:
12,000 * 2.13 = 25,560 Effective Life


That's a 5,100 difference in raw damage between two tanks who think they are at similar standing. Or, to put it in more familiar terms, that is the difference between a Warrior comfortably tanking a lvl 70 Patchwerk and a Warrior regularly getting one-shot by same.


Now let's run some numbers to see how very basic consumables affect tanking. I'll use just a Flask of Fortification and a Stoneshield Potion on our first tank.
16,000 Armor
14,500 Health

14,500 * 2.51 = 36395 Effective Life

This means that with just these two potions, a tank has increased the damage he is able to withstand more than 17%.



Conclusions
1) Even though this may sound obvious, it needs to be repeated that every increase in Armor gives linear and potent scaling to the effectiveness of Stamina. Every increase in Armor is a direct increase in the effectiveness of Stamina; every increase in Stamina is a direct increase in the value of Armor.

2) With the above in mind, the Vitality talent needs to be evaluated for total merit. While a tank may complain that Vitality only gives them a 600 health increase, they fail to recognize the effective health gained is generally going to be more than twice that.

3) Solid Star of Elune gems should be viewed under the same principle. While Avoidance gems such as +Defense and +Dodge gems will always offer a precise, static damage reduction, a Solid Star of Elune can scale in many raid situations to be the equivalent of over 30 Stamina.

4) There are a few people who have made comments regarding why Avoidance stats may be better. One poster mentioned that he would rather have 10% Dodge from gems than Stamina. The equivalent of that 10% Dodge would be 2,835 HP, which, given his Armor, would in turn increase his Effective Life by over 6,000. In other words, if he focused on Stamina, he could take hits from a full raid zone beyond his current capability. Need proof? Look at the Armory profiles from tanks in the top-progressing guilds worldwide.

5) If you have enough Stamina, the most effective means of increasing survivability as a tank is to increase Armor at the cost of other attributes. In particular, when facing an enchant choice such as that of +12 Dodge to Cloak or +120 Armor to Cloak, a Stamina heavy tank will definitely find greater benefit from the +120 Armor.

6) Increasing Stamina is not always the best method to increase Effective Health. When making a choice between Armor and Stamina upgrades, you will often find that Armor will give you a higher Effective Health than Stamina.

7) The choices between Stamina/Armor and Defense/Avoidance should only come when evaluating near-equal pieces of gear. Gems are a generally good subject because they are naturally equal in item level. One smaller point to remember is that Avoidance always takes a 7% hit on overall damage reduction due to the combat table -- 1% Dodge is actually only 0.93% damage reduction once the additional damage from Crushing Blows is factored in. When dealing with items of significantly different item levels, common sense applies.


8) It's not about balance. Like tanking weapons, where faster is always better, when tanking new encounters, Stamina and Armor are always better. The set you use to tank new content should always have the highest Effective Health possible. As you get comfortable with an encounter, you wear more Damage Reduction gear (Armor/Defense/Dodge). This is a hard and fast rule.


In Summary
Like always, this is not written to help the casual tank. It is written only for the tanks who are pushing through content beyond their gear level and wish to do it more effectively. This is what the Stamina Warrior is, and I write this just as passionately as I did over a year ago with "Miles to Go."

I deeply respect people like Emeraude, who championed the Defense/Avoidance/Agility/Armor tank theory. I remember seeing a great Twin Emperor's combat monitor from Emeraude. I fall squarely into the Stamina/Armor/Strength/Block Value camp, and many months ago we used to have great arguments on these forums.

I understand the irony of having a Druid post an article about Stamina and Armor. One of the old catchphrases of these forums was that Avoidance is what sets Warriors apart from Druids. I will make this absolutely clear -- Avoidance is good (especially Dodge, as Wanderlei has clarified). You will find great pieces of incredible Avoidance gear such as Boots of Elusion. Defense is good. You want and need these stats, and you will get them with much of your tanking gear.

With tanking new content, one rule is important -- it's not about taking less damage; it's about being able to take more damage.

Thanks,
Cider



Addendum (1):
Shield Block Value and additional Effective Health
The Effective Health shown on this website is reliable and accurate. However, there is an additional, scaling bonus to your Effective Health in the form of Shield Block Value. This is the secondary scaling of Shield Block Value (the primary scaling is already included in the equation here).

In addition to increasing your Effective Health by a base amount -- exactly like Health -- it also decreases a percentage of damage taken. However, the percentage decrease cannot be quantified without detailed information regarding the attack speed, average damage, and maximum damage of your enemy.

Consider the difference between going into a 5-man or Heroic instance with 500 Block Value and going into a fully realized raid boss encounter with same. The percentage reduction -- and your total Effective Health -- will be different for each encounter. Where you might gain limited advantages to Mitigation against some bosses, others, such as the Prince in Karazhan, will yield far better returns with Block Value. In some cases, especially in world farming, Effective Health can multiply several times over due to a state of near-invulnerability.

Shield Block Value is the stat with the highest potential in the Effective Health equation. It shares a unique relationship with both Health and Armor. Armor is a curved mechanism for increasing Mitigation; Shield Block Value, however, is a linear mechanism for increasing Mitigation. In other words, Shield Block Value does to Mitigation what Health does to Life.

Shield Block Value gains the same benefit as Health when factoring in Armor. As Armor increases, the value of each point of Shield Block Value increases. Then, as the value of Shield Block Value increases from Armor, the value of Health and the impact on Effective Health increases unpredictably -- unless we know the incoming damage values.

However, keep in mind how limited Shield Block Value is on gear. Reaching 1,000 Shield Block Value, for instance, is virtually impossible without the use of trinkets or the Tier 5 Shield Block Value bonus. Blizzard most likely itemizes large amounts of Block Rating -- a near worthless stat for Warrior raid tanks -- to keep item levels and potential Block Value in check. Unfortunately, this also extends to gem choices, and it is this reason -- not potential Shield Slam damage -- that we are unlikely to see many Block Value gems on the horizon.

Complex? Sure. Bottom line: don't write Shield Block Value off for it's Mitigation value.

Thus, Avoidance also helps reliably keep Effective Health high. By increasing Avoidance such as Dodge, you simultaneously decrease the chance of incoming attacks not being avoided or blocked. Indeed, increasing Avoidance will keep more Shield Block charges active for longer, and with enough of it, you become virtually immune to Crushing Blows in most encounters.

This isn't to say that you need to go gem everything with Avoidance. Please note the wording in bold -- it will not increase Effective Health. It will only help stabilize your rate of effective Shield Blocks, which in turn allows Block Value to be reliably factored in. Heavy Avoidance is only important for some boss fights -- boss fights you would probably use some Avoidance gear for in the first place. Also, Warrior equipment is already unusually weighted with Avoidance stats, and you gain plenty through normal gearing.



The original thread and all of the outstanding responses can be found here:
WoW Forums -> Effective Health, Armor, and Gemming/Gearing

[Ciderhelm]

Wanderlei's Response:


Effective health is extremely important - up to the point where you have enough to survive a single hit (or simultaneously combination of hits such as arching smash/mighty blow or a thrash). And when pushing new content, if you don't have enough effective health, then you might as well not bother.

I really like armor, I think it's a good stat to stack because it works well in every situation (well, almost) - it provides a reasonable reduction in damage taken, and helps raise your effective health considerably. Right now, I have little over 12k armor, and I consider it a serious weakness of my gear... unfortunately getting it to where I'd like to (13.5K+) requires tanking loot to drop, which is apparently asking a lot (ok I'm finished ranting on that point).

I also strongly believe in having a variety of gear. I've been trying (largely unsuccessfully due to bad loot luck) to build a set that maximizes effective HP to complement my normal, avoidance-focused set. And there are certainly situations when pushing new content that subbing in some of that extra health at the expense of avoidance is beneficial. However, I still believe that represents the minority of situations.

Health can also push you over the amount of effective health you need to succeed, but once you are past that point, additional health does not do much for you. I'd be interested in a mod that kept track of how much "overkill" damage you recieved upon dying - I think it would have great applications in gear selection for a particular encounter, but my impression is that when I die, it is typically not a situation where 500 or 1000 more actual health would have saved me. It is occasionally, no doubt, but I think that represents the considerable minority of my deaths.

Basically, while I agree that it is important (required) for progression to reach certain benchmarks with regards to effective health, I have serious doubts that the barrier to progression is often the fact that the main tank does not meet the required effective health. It may be occasionally - especially if inadequate consumables are being used, such as when we first started gruul's lair, but the "ugly truth" in my opinion is that the cause of wipes is not generally a mathematical formula, but plain and simple player error. Dumping a little too much rage into heroic strike, taking a preventable crushing blow, and dying is player error. There are many nuances to healing as well that create inevitable player error even more so than tanking, since it is not only an issue of individual timing, but coordination among healers.

The advantage of higher avoidance, in this case, is rather complicated. A dodge can salvage a player error and make it as if nothing ever went wrong. Can you rely on it? Of course not, but the errors that result in tank death are usually only prevented by extreme differences in health and armor. To me, this really illustrates a difference in mentality: as an avoidance tank, I do not try to survive the worst-case scenario. I am willing to concede that as a wipe, run back, pot up, and do it again. Very few raid boss encounters are a marathon in the sense that you recieve so many attacks over the course of the fight that it is statistically probably that you will experience a very bad string of back luck with regards to avoidance at some point during the fight. When fighting a boss you are undergeared for, I think it's better to be lucky than good. After all, you only need to kill the boss once, and the number of tries you have is not usually limited by game mechanics, only by the players' time and willingness.

Avoidance reduces the chance of a bad damage spike that could potentially kill the tank regardless of how much effective HP he might have, and it reduces it at an accelerating rate. Take for example the chance that, following a hit, you will recieve three more hits as well without avoiding any of them:

At 30% avoidance, the chance is 0.7^3 or 34.3%
At 40% avoidance, the chance is 0.6^3 or 21.6%
At 50% avoidance, the chance is 12.5%
At 60% avoidance, it's 6.4%
At 70% avoidance, it would be only 2.7%

Now, at each of these increments the difference in commensurate effective health is obviously large but, unless the tank with higher avoidance fails to meet the minimum required effective health for the fight, the tank with higher avoidance will suffer far fewer strings of hits which, if a player were to make an error, might well result in the tank dying.

The chance of recieving a crushing blow against a mob that hits exactly three times per shield block cycle in a single shield block cycle exhibits a similar relationship:

At 30% avoidance, the chance is 0.7*0.7*0.15 or 7.35%
At 40% avoidance, the chance is 0.6^2*0.15 or 5.4%
At 50% avoidance, the chance is 3.75%
At 60% avoidance, it's 2.4%
At 70% avoidance it would be 1.35%

This is because while armor scales linearly - each additional 1000 armor provides the same benefit as the one which preceded it, every point of avoidance provides MORE reduction in damage than the point which preceded it, and reduces the chance of burst damage both through consecutive hits and by crushing blows by a larger margin.

Basically, in order to subscribe to the theory of maximizing effective health for raid progression, I would have to be convinced that effective health is indeed the limiting factor on progression - that each successive fight requires more effective health than the one before it, and that it is by increasing your effective health to meet the new requirement that progress occurs. If it is not, then the benefit of reducing the number of potentially fatal damage spikes in a way that scales BETTER than linearly offers a greater benefit. In a game of roulette, you want to take as few shots as possible. Unless the game can be played perfectly (doubtful) then the combination of player error and bad fortune can result in a wipe on a new raid encounter. You can reduce the number of errors only through practice, but you can reduce your "bad fortune" through avoidance. And in so doing, you take fewer shots with the gun to your head and thereby increase your odds of survival.

[Ciderhelm]

Cronedog's Response:

You go about showing the correct relationship between AC and stamina, but dont seem to notice that that relationship extends itself equally well to avoidance.

If you have X HP and it takes Y number of hits to kill you then

50% AC will make every hit do half the damage, making it take 2Y hits to kill you.

50% avoicance will make every other hit (on average) not hit you, thus 2Y hits is needed to kill you.

In this regard they are exactly equivalent. The only difference is that AC will have a smaller root mean square difference. In less technical terms, you will get more or less then 2Y hits on extreamly short scales. Some people that dont well understand statistics will argue that you may never actually dodge, well that is true, but by the same token you may never crit. The variability will die out fast as time grows.

As a slightly less technical approach, let us examine an example.

You have some life pool that takes a certain mob 10 hits to kill you (or 10% per hit) if you had 0 AC and 0 avoicance.

If you have 10% DR from AC, each hit will take away 9.09% of your life per hit, which will take 11 hits to kill you.

If you have 10% avoidance, each hit will take away 10% still, but you will take 0 damage every 10th hit. Thus it now takes 11 hits to kill you.

The odds that 10% dodge will do nothing in 10 hits is the same that it will avoid 2 attacks in 10. These events will occur once in a hundred attacks.

Ciderhelm, I respect you a lot. Please read this as just constructive critism.





We have established that AC reduction will do the same as avoidance reduction, let us examine their interaction.

50% dodge and 50% reduction from AC combine multiplicativly to give 75% DR. (much like on sale items in clothing stores)

This is to say that if you are at X% avoidance and Y percent AC reduction, that adding 10% to either will give different results. It will always be better to give 10% to the higher one.

example 1
23% dodge
14% AC reduction
77% of hits land, and do 86% damage for a total of 66.2% damage taken, or 33.8% total DR

example 2
it is important to note that
14% dodge
23% AC reduction
86% of hits land and do 77% damage yields the same 66.2% damage taken or 33.8% total DR

what does 10% more AC reduction net from example 1
23% dodge
24% AC reduction
77% of hits land and do 76% damage for a total of 58.5% damage taken or 41.5% total DR

what does 10% more dodge reduction net from example 1
33% dodge
14% AC reduction
67% of hits land and do 86% damage for a total of 57.6% damage taken or 42.4% total DR

Let us do one more, adding 30% to example 2

30% dodge to example 2 nets us
44% dodge
23% AC reduction
66% of hits land and do 77% damage yields 50.8% damage taken or 49.2% total DR

30% AC to example 2 nets us
14% dodge
53% AC reduction
86% of hits land and do 47% damage yields 40.4% damage taken or 59.6% total DR

Thus again showing that the stronger stat getting the boost is the best way to go.
What happens if we split this evenly as 15% more aC and 15% more dodge?

29% dodge
38% AC reduction
71% of hits land and do 62% damage yields 44% damage taken or 56% total DR.


At this point you may be thinking, "holy crap cronedog, this doesn't prove balance is key, you just shot yourself in the foot". Hold on, I'll get there.


Note the fact that the average between 30% dodge and 30% AC would have net you 54.4% DR, which is less then the 56% that you get from 15% dodge and 15% AC.

Why is this significant? From the blizzard itemization formula. I'll spare the gory calculus and algebra details and try to show this intuitivly through examples.

Excessily stacking a stat comes at a price. For example if you get 2 "of the monkey" rings, you get more total stamina and agility then having 1 "of stamina " ring and 1 "of agility ring"

Take the drakeclaw bands for instance

Drakeclaw Band of Agility
+15 Agility
Equip: Increased Defense +6.
Item Level 54

Drakeclaw Band of Stamina
+15 Stamina
Equip: Increased Defense +6.
Item Level 54

this yeilds 15 agi and 15 stamina

Drakeclaw Band of the Monkey
+10 Agility
+10 Stamina
Equip: Increased Defense +6.
Item Level 54

2 of these yields 20 agility and 20 stamina.

From this I hope it is clear that balance is in fact key.

[Ciderhelm]

My Response:


First, Cronedog, you are absolutely correct in your math. The relationship between Avoidance and Stamina/Armor is critical, important, and helpful.

One thing that has always been true of my posts is that I don't give enough credit to balance (wait, didn't I just say not to balance?). If I write something about Stam/Armor, the best you'll see is a few comments that "avoidance is good" at the bottom (which are here, buried in the Summary section). The fact is, I do value avoidance greatly, and have put alot of time into researching them as hopefully the research on the Parry counter-attack has shown.

Let me provide a little context. There are several threads on these forums asking about gems. Two of them bring up main tanks such as that of Death & Taxes, and there is open debate as to whether gemming every slot with +12 Stamina makes sense. If you notice, these same tanks have +Armor rings and, while they do have avoidance like any tank should, they are Stamina/Armor tanks.

This isn't about ignoring one stat or the other. It's about making small gear decisions or, in the case of gems, bigger gear decisions. A good tank will always have good Defense and Avoidance and Stamina regardless of their subscribed theory.

Hopefully I can clarify this in addition to my earlier comments with the following comparison.


Defense/Dodge/Parry/Armor/Agility is required for top efficiency. For content you are comfortable with and content within your progression level, you always want to increase these stats. Any increase in Avoidance will always provide a good decrease in damage taken over a period of time.

From a Healer's point of view, a tank stacked in Defense/Dodge/Parry/Armor/Agility is a more efficient object. On a fight they know inside and out, the Healer will have an easier time healing this tank assuming the bare health minimums are met.

Take note that I consider a Defense/Dodge/Parry/Armor/Agility tank to be a balanced tank. They also have Stamina, but they balance it equally with other stats.


Stamina/Armor/Strength/Block Value is required for maximum progression. For tanks who are well beyond their progression "capability" by normal standards, maxing out Stamina/Armor becomes not only important but necessary. For instance, a player might be suited to tank a boss which deals 25,000 damage with no problem, but what happens when that same player faces off against the boss that hits for 35,000? 40,000? 45,000? These numbers always scale up, and for progression-based tanks such as those in top-progression guilds, increasing Stamina/Armor beyond any other stat isn't debatable, it's doctrine.

As each new boss drops, new gear drops, and the Stamina/Armor tank picks up gear well beyond the equivalent gear for a Defense/Dodge Warrior in terms of item level. Over time, the Stamina/Armor tank will have equally efficient Stamina/Armor gear when compared to the lower item levels of the Defense/Dodge tank who can only successfully survive smaller-hitting creatures. With this, the Stamina/Armor tank will also have a heavy lead in actual raid progression, assuming the guild and raid mechanics are sound.

This is not to say these tanks ignore the other stats -- tanks who subscribe to this will always be using heavy consumables, putting them at well above 500 Defense with good Agility/Dodge, and even more Stamina and heavier Armor.

From a Healer's point of view, a tank stacked with Stamina/Armor/Strength/Block Value is a more forgiving object. On new fights where a creature has unknown or very powerful strikes, a single hit might bring the Stam/Armor tank to 40% life. To the Healer, this means that the tank can sustain auto-attack damage until he or she can reactively heal. Keep in mind that even if the tank does avoid an attack, especially on unfamiliar encounters, oftentimes the heals will still be landing.


This is not to say common sense doesn't apply. Since the gear difference between a Stam/Armor and Defense/Dodge tank aren't actually that big (primarily Gems being the hot issue), no Warrior should subscribe to one camp at all times.

Patchwerk is a perfect example. Our first 2 or 3 times through Patchwerk the tanks all wore heavy Stam/Armor gear and it served us well enough. Since it was new content, our healers had Flask of Distilled Wisdom running. Once we were comfortable with our damage intake, we started switching in more and more avoidance gear; this quickly got rid of the use of Distilled Wisdoms (well, that and deciding to recruit more than 12 healers).

You have to be somewhat self-thinking. Avoidance gear is like Shield Block gear in that there are times when it is plainly obvious -- on new content -- that it's better. When a boss deals heavy elemental damage or simply doesn't want to deal enough damage to kill you, it makes no sense to go Stamina/Armor heavy -- let the flask and ironshields take care of it.


It is not always a question of efficiency. Sometimes, it is a question of effectiveness. It's not about taking less damage, it's about being able to take more damage. The tanks people are observing, such as those from D&T, Nihilium, and other top guilds who have stacked Stamina/Armor are doing it with a method and reason.



Anyway, Cronedog, as usual I agree with your math and respect the post. I disagree with Avoidance when progressing significantly beyond your gear level. I agree that Avoidance is a clear and potent damage reduction when coupled with Armor. Also, your note on itemization penalties is important for tanks to recognize as well.



On a sidenote Cronedog, I want to bring up one thing to think about that (hopefully) you can give a better answer for than I can. Crushing Blows can't all be blocked even by the most astute Warrior, because a certain number of them will get through if the creature attacks quickly.

Let's assume I'm a Druid (for simplicity) for a minute, and I have a 30% Dodge. Since I eat all the Crushing Blows, I will take 150% damage 15% of the time. If I'm doing my math correctly, this means that every 1% Dodge will have a 7% penalty (or, 1% Dodge is 0.93% actual Damage Reduction, since Dodge can never affect the Crushing). Thus, the Druid's 30% Dodge is actually only 27.9% Dodge in terms of real avoidance.

Those numbers are made up, by and large, and I used the Druid because I assume they can't mitigate Crushings. A Warrior would obviously not take the 7% penalty, but they would take a penalty nonetheless. How does this factor in?

[Ciderhelm]

Socc

A quick question as it relates to mitigation. You essentially point out that armor mitigation makes STA more effective, as you will lose less of it for every point you have. In so doing you created a formula to show the effective value of stamina. My question is would this not also translate to avoidance. if you had 50% avoidance, would that not effectively multiply your effective stamina by 50% as well? Yes is a more fits and starts manner, but it is a very similar principle.



Amberlina

There's a big flaw in your analysis. While druids can relatively easily trade armor for avoidance, it is very hard for warriors to do the same. Aside from the +120 armor cloak enchant and rings, a warrior stacking avoidance and a warrior stacking stamina will have armor values within a few hundred points of each other. Unless the item has had itemization points specifically diverted to giving it extra armor (which is rare), two different ilevel 100 epic gloves, for example, will have the same amount of armor. Therefore, when comparing avoidance vs. stamina for warriors, armor should be considered a constant. At most, there might be a 500 armor difference between the two, definitely not 2000.



Maldian

Cronedog, notice that he also mentioned Murphy's Law, which is an important point in favor of armor over avoidance. Armor is always there in a constant, predictable amount, on every single bit of incoming (physical) damage that you take.

If your dodge roll is bad and you take 10k hits back to back, you are dead. On the other hand if you had armor instead, you can take back to back 7k hits and get healed back up. Healers like healing predictable damage. Avoidance is a chance, armor is a guarantee.

If you have a choice between an exactly equal amount of total damage prevention from armor or from avoidance, armor is *always* the superior choice. Always. From soloing to normal mode dungeons to cutting edge raid tanking. The damage prevention must be greater from the avoidance for there to be any discussion at all. (Note that this is the case in stamina/effective health vs. avoidance, since stamina offers substantial survivability, but no damage prevention at all. That is why there is a discussion necessary. If the discussion were purely armor vs. dodge, there would be no discussion, we would just all take armor.) When the avoidance does offer significantly better damage prevention, only then is when you have to make a judgment call about whether the fight you are tanking calls for less total incoming damage or more predictable/healable incoming damage.


Omleet

The difference between avoidance and stamina (not avoidance and armor - as someone pointed out, the only stats we warriors can realistically make tradeoffs between are avoidance stats and stamina.) is this:

Avoidance lets healer mana last longer.
Stamina lets us survive bigger hits.

We have minimum stamina levels required for a given fight, and stamina beyond those points drops off in value very rapidly.
Meanwhile, avoidance never drops in value.


Now, it is probably the case that to push the cutting edge in raid content, we have to stack stamina, because bosses hit us really hard. But avoidance will always be useful.

To summarize: Increasing our stamina may enable us to tank a fight we simply couldn't tank before, but increasing our avoidance will improve our chances of succeeding in fights we were already capable of tanking, even if we were having troubles.

So ... yes, lots of stamina is good. But when deciding which set to use, or how much stamina to stack, look at what happens in the cutting edge of your guild's progress.
Do you get oneshot or otherwise killed by too much damage in too short a period of time? If so, more stamina. If not, get more avoidance.

[Ciderhelm]

My Response:

A quick question as it relates to mitigation. You essentially point out that armor mitigation makes STA more effective, as you will lose less of it for every point you have. In so doing you created a formula to show the effective value of stamina. My question is would this not also translate to avoidance. if you had 50% avoidance, would that not effectively multiply your effective stamina by 50% as well? Yes is a more fits and starts manner, but it is a very similar principle.

Yes, this is true. Cronedog illustrated this well.

However, the crucial difference lies in the raw damage being dealt to you. If you meet the health minimums on a boss, having high Avoidance will be very good. It is also good because every percent damage reduction (from Avoidance or Armor) is an equal percent healing aggro reduction, so for 5-man, Heroic, and some raid situations it is simply alot better to stack Avoidance.

The problem is that true Effective Health can never be increased by Avoidance. Let's say you had 25% Avoidance, 50% Damage Reduction from Armor, and 10,000 Health. If your Avoidance fails and a creature hits you for 20,000 raw damage, you will die. Let's say you raise your Avoidance to 50% with the same stats, and the boss uses the same attack. It may get avoided once, twice, three times, ten times if you are very lucky, but eventually that Avoidance will fail. You get hit for 20,000 and die. But if you raise your Damage Reduction from Armor, you will live.

It should be a question of what you are fighting in relation to you. As Maldian correctly pointed out, the theory is as true for anyone at any level in their character development, as long as they are fighting creatures that they are seemingly incapable of tanking. If you are on a slower path in terms of progress -- which is fine -- then Avoidance is just smarter, as your Effective Health will always be high enough to survive and you can only become more efficient.

There's a big flaw in your analysis. While druids can relatively easily trade armor for avoidance, it is very hard for warriors to do the same. Aside from the +120 armor cloak enchant and rings, a warrior stacking avoidance and a warrior stacking stamina will have armor values within a few hundred points of each other. Unless the item has had itemization points specifically diverted to giving it extra armor (which is rare), two different ilevel 100 epic gloves, for example, will have the same amount of armor. Therefore, when comparing avoidance vs. stamina for warriors, armor should be considered a constant. At most, there might be a 500 armor difference between the two, definitely not 2000.

I'd agree with you to a certain extent. Certainly, since "Miles to Go," it's been reiterated several times that we aren't talking about big differences, just many smaller choices. However, gems make up a sizable cost investment and chunk of itemization, and are important enough to be addressed.

The difference between tanks, though, is bigger than it seems. The numbers I used are very real numbers I've seen from Warriors. When I went inactive, I had ~14k health and 14k Armor if I recall correctly.

I hope he doesn't mind, but let's look at Cronedog's Armory. He has incredible Avoidance stats (over 36% pure Avoidance). I have no doubt he's a skilled tank. He has, however, 11,700 Health and 11,000 Armor.

The 12,000/12,000 numbers I used are a benchmark for many people. I didn't make that number up out of thin air, and there really is a big gap between equally-progressed tanks. What many don't realize -- and I hope they see here -- is that they have so much more potential than that. If you can pull 13,000/14,000 you will be that much more capable taking huge hits from boss mobs. It's not the most efficient, but it allows the best progression.

To summarize: Increasing our stamina may enable us to tank a fight we simply couldn't tank before, but increasing our avoidance will improve our chances of succeeding in fights we were already capable of tanking, even if we were having troubles.

This is put very well. Thank you.



In the ever-so-eloquent words of Rocky,
"But it ain't how hard you hit; it's about how hard you can get hit, and keep moving forward. How much you can take, and keep moving forward. That's how winning is done. Now, if you know what you're worth, then go out and get what you're worth. But you gotta be willing to take the hit, and not pointing fingers saying you ain't where you are because of him, or her, or anybody."

[Ciderhelm]

Saberoy

my brain hurts.

[Ciderhelm]

Bump For Great Justice

[Anvilbreaker]

So, where does the 10% reduction from defensive stance come into play?

[Crimsonstorm]

It was reading all of this discussion, several months ago, that convinced by to change from an avoidance tank to a stamina/armor tank. Before that I was obsessed with avoidance. This stemmed from my experience running 5 mams. In 5 mans, avoidance is better. Because it is a situation of multimob pulls, with lots of mobs each not hitting very hard, and 1 healer.

At the time I had 58% miss+parry+dodge, with around 12k hp and armor.
Now (with a LOT of gear upgrades, and changes), I'm at 16k hp 17k armor with 45% miss+dodge+parry. (Yeah, much of the gain is upgrades).



Key Points, imo, which favor stamina/armor/block value over Avoidance, for RAID tanking:

1) The manner in which healing is performed.

In a 5 man, the healer waits for you to take damage, then casts a heal. Avoidance translates directly into mana saved, so you seem very easy to heal with high avoidance. You never die of burst damage in these situations.

In a raid, about 3 healers are spamming heals on you BEFORE you take damage. They may cancel them if you dodgethe attack, but maybe not. Also, mana is much less of an issue when raid buffed. There is almost no difference to the healer if you dodge the attack vs take it (unless its the one that kills you). The heal is coming either way.

This is the primary factor which favors stam/armor. The healers dont care if you dodge in a raid. They do in a 5 man. Also, you DO die to burst damage in a raid situation, so you must maximize effective health.


2) Aggro generation. With very high avoidance, your rage generation is erratic. It comes in big bursts, but there are periods where you dont get it. This can cause you to run out of rage and not be able to use abilities, and at worst, not be able to put up shield block! It also makes it almost impossible to spam heroic strike, which requires a lot of incoming rage. Lower avoidance tanks generate more aggro due to being able to heroic strike more often, and not running out of rage much.

Avoidance at some point reaches a level where stacking more of it hurts you, because your rage generation becomes inconsistent and you cannot reliably hold aggro anymore. This doesnt happen with stamina or armor (more armor does result in somewhat less rage, but it still comes reliably over time, not in huge bursts, so it is manageable). An avoidance tank eventually reaches a point where they cannot continue stacking avoidance or else they will be unable to hold aggro.

3) Stuns/CC/incapacitation. At various times, you will be stunned, or afflicted with some other effect, and will be unable to dodge/parry. These times force the 'murphy's law' worst case scenario on you. Youre going to be hit every time, your avoidance wont work, youre taking every hit. Only stamina/armor help in these situations, avoidance does not. This is a big deal on certain single mob trash pulls that stun you. These mobs often hit extremely hard (almost raid boss-like), and when they stun you, they can easily kill you if you are an avoidance tank, and rely on dodging hits.

4) Magic Damage. Again, avoidance here is worthless, only stamina helps here.

5) More reliable indication of when to use cooldowns to save yourself. This is an interesting one. It is important to be able to use shield wall/last stand/healthstone etc, to save yourself from burst damage situations.

Lets compare two tanks. One will take the boss 4 hits to kill, and has 40% avoidance. One will take 3 hits to kill, and has 60% avoidance.

Periodically, the tanks will take two consecutive hits without a heal. this happens more often for the stamina/armor tank who has less avoidance, but it does happen for both. Whenever this happens, the stamina/armor tank is still fine. Another hit will not kill them, they can afford to wait a couple seconds for the heal. Only if another hit lands before the heals must they use an cooldown to save themself. However, the avoidance tank is in extreme danger. If another hit comes before the heals, and they dont dodge, they die. (40% chance). They must now use a cooldown.

Periods where the tank takes 2 consecutive hits with no heals (at 60% avoidance - 16% chance of 2 straight hits), will occur much more often than periods of 3 consecutive hits without heals (thats much more time to get off that heal, and its about the same chance for the 40% tank to take 3 hits in a row as the 60% to take two).

Thus, the stamina/armor tank has many less 'scary' times when they must use a cooldown, thus better conserving their cooldown.


6) Crushing blows. Yes, the avoidance tank gets crushed less by those fast hitting mobs that get more than 2 hits per 5 seconds. BUT there are also occasional times where the tank fails to hit shield block every 5 seconds, and is crushable. This would be the same for either type of tank (its player skill). The stamina/armor tank has a much greater chance of not being killed by the crushing blow than the avoidance tank, and thus not paying for their mistake.


7) Synergy of armor and block value. (Note, this is just like the synergy of armor and stamina. Block value is like stamina in its contribution to effective health). Block value is something we should be stacking for threat generation, so lets assume we're already going to have a high block value. Very large block value increases the value of armor and vice versa.

Lets say a hit is coming in for 5000, and we have 60% armor mitigation and 500 block value.

It goes: 5000 * .4 = 2000 * .9 (defensive stance) = 1800, -500 = 1300 taken. Adding 100 block value (after talents) takes another 9.2% or so off the hit!

Now lets say we have only 50% armor mitigation:

5000 * .5 = 2500 * .9 = 2250 - 500 = 1750. Now 100 more BV is a 'mere' 5.8% taken off.


The more BV you have, the more effective armor is, and the more armor, the more effective BV is. This is very relevant on a boss where you essentially are blocking every hit due to shield block.

[Ciderhelm]

Adding one thought spurred on by a comment Cronedog made.

There is a difference between Health and Armor in the Effective Health equation. With equal Effective Health, the tank with more Health will be more Rage efficient; the tank with more Armor will be more Mana efficient.

[Geeko]

Has anyone posted the minumum Effective Health required for any/all raid bosses in TBC? If so please link, thanks. I am looking to go farther down the arms tree for threat, and need to drop Vitality to do so. With Vitality, I am 15k HP unbuffed, and 16.8k AC

[Ciderhelm]

No, that's a long-term goal for this site. We need a mod author to really help us put this together and form a database of how hard creatures are hitting.

I think there could be some basic guidelines posted, I'll check. Do you have a particular zone you are interested in?

And, you stole my Dolphin Olympics title.

[Geeko]

Its nice to be on top! We'll see how long it lasts though...

I need to be sure I can tank the Kara bosses, so I suppose Prince, or Nightbane would be the binding constraint.

[Ciderhelm]

Yes, you can, you are well beyond what is necessary for either of those fights. You are fine for starting SSC/TK (and everything up to that point) as well.

Per point of reference, I took Nightbane/Prince at 13k/14k when I first did Kara. It was rought, but doable. Your stats are well beyond that.

[Cadmann]

I've got to ask...

How in the heck did anybody reach 15k unbuffed HP and 16.8k AC pre-Kara?

We've been farming Kara forever, 2/6 SSC and 1/4 TK, farming Gruul etc., and I'm at around 15,500 unbuffed in stamina gear with 17,500 unbuffed AC.

For most of our Kara runs I was far, far less than that - do you just have a ton of Heroic gear, or are you wearing Gladiator's stuff and are way down on Defense or something?

/boggle

[Vakfaroosh]

Cadmann,

It is not hard to reach those numbers pre Kara, if you are a blacksmith you can get several upgrades, plus there are two 51 stam cards from darkmoon (that is 102 Stam). Also remember all the craftedable epics, heroic drops, et al.

[Soulonn]

Yea, it'd be pretty easy to get those numbers pre-kara. I'm almost at 13k unbuffed, and I hardly put effort into it. The question is WHY?! You can start tanking kara way before you reach 15k, I would think...

[Cadmann]

I'm going to have to guess (lacking an Armory link) that the difference between our gear sets is going to primarily appear in +block value and avoidance stats?

I have literally every single drop available to me from every boss in Kara, the crafted third-tier smithing breastplate, 4 pieces of tier 4, the Red Havoc Boots from the SSC pattern, Void Reaver's bracers, the netherwing trinket and the Spyglass of the Hidden Fleet (I can't get the aces for Lunacy or Furies no matter what I do, seemingly), Lurker's mace, Gyro-Balanced Khorium Destroyer, and I only have 500 more unbuffed hp and around 1k more armor than a guy who hasn't been to Kara?

Incidentally, I'm MS specced and logged out in DPS gear at the moment, so ignore the signature.

[Kazeyonoma]

tauren racial might come to mind, nd also are you gemming for pure hp?