This is a quick "Beginner Theorycraft" article to explain the basics of the Attack Table to new players. Most of the basic defensive examples were "borrowed" from Winchester's guide, but I've tweaked a few numbers and added a significant amount of commentary. I've also added a large section on the offensive side of things, so that we have a place to point new players who want to know why hit/expertise are good threat stats for them.

This is designed to be a "tutorial," which means "readable by someone who's just getting their feet wet in tanking theory." It's debatable whether this should be in Basic Training or Advanced Training, but since it matches the level of Winchester's guide I chose to go with Basic Training.

Any comments/questions/suggestions are welcome, especially those that further enhance the readability of the guide and the quality of information it contains.

Basic Training 101: The Attack Table

To understand some of the gearing choices a paladin has to make, we first need to understand how WoW resolves combat events. The fundamental mechanic is something called the Attack Table.

Every time a player or boss attempts to make an attack, the game rolls to determine whether the attack succeeds or fails. The Attack Table is the scale which determines the results. To illustrate this, let's look at a few simple examples. First, let's consider a lvl 85 mob attacking an un-specced lvl 85 paladin with base avoidance (5% miss, 5% dodge, 5% parry, 5% block). The attack table is then constructed like this:

the server then does a /roll 100 to determine the outcome (though it does this to more decimal places than a standard /roll 100). If it rolls a 12, you parry; a 16 is a blocked hit; a 22 is a critical strike, and anything over 25.00 is a regular hit.

If instead we're considering a level 88 boss attacking a level 85 paladin, we have to make a few modifications. For each level above 85, the boss gains an additional 0.2% chance to crit and reduces the chance for his target to avoid or block an attack by 0.2%. Thus, we've now got a 5.6% chance to be crit, and our base chance to dodge, parry, block, and miss are now all 4.4%:

Before moving forward, let's briefly discuss how the table is arranged. As you see, avoidance is at the very top of the table, followed by block, followed by crits, followed by regular hits (which fill up whatever remains of the attack table). Note that blocks and crits/hits are separate entries on the table - this means that you can never block a crit, for example.

As you increase the chance to do any one of these things, it "pushes" the things below it further down on the combat table. As an example, if we let our example paladin chose the protection tree as his specialization, he will gain 18% block from our baseline 8 mastery. That extra block will "push" crit and hit further down, and as a result 18% of the hit chance will be "pushed" off of the end of the combat table. The net result will be that we'll still have a 5.6% chance to be crit, but the chance to block will be up to 22.4% and the chance to be hit will drop to 58.8%:

As tanks, we want to take as little damage as possible, which means we want to reduce the chance to be hit or crit as much as we can. In previous expansions, we had to stack defense rating to remove crits from the table. With the massive overhaul in 4.0.1, defense rating went away and every tanking spec gained a talent that reduces the chance to be critically hit by 6%, which is enough to remove them from the table for a raid boss. For paladins, that talent is Sanctuary. So if we let our example paladin spec deep enough into Protection to pick up 3/3 Sanctuary, the combat table looks like this:

Now that we can't be crit, our aim is to reduce that 64.4% chance to be hit by pushing as much of it off of the table as possible. There are two ways to do this:

Stacking mastery is the most efficient way to get rid of hit, since it's unaffected by diminishing returns and has a very favorable rating->% conversion (~179 rating gives us 2.25% block). Now that block shaves a full 30% off of a hit, and 50% while Holy Shield is active, it's an incredibly powerful damage mitigation stat.

Stacking avoidance also removes hit, though at a slower rate because the conversions are less favorable (~177 rating for 1% avoidance) and subject to diminishing returns. However, stacking avoidance means you'll replace those hits with avoids, so you're replacing a result where you'd take damage with one where you take zero damage.

The consensus at the moment is that it's far better to stack mastery than avoidance if we have the option. Despite the diminishing returns on avoidance, mastery and avoidance are both similar in effectiveness for reducing overall damage intake. However, mastery smooths out damage intake by reducing the number of full-sized hits you take, which means your healers have more time to react and can conserve mana by using slower, mana-efficient heals.

So let's give our paladin some gear and see what happens. Let's say he gains enough mastery to reach 35% total block chance, and enough avoidance to reach 10% dodge and 10% parry. Now the combat table looks like this:

What if we jump forward in time a bit and think about later tiers of content. Let's say he's managed to bring his dodge and parry up to 20% each, and stacked enough mastery to reach 56% block. The attack table then looks like:

At this point, we've pushed hit completely off the table. We now have a 45% chance to avoid the attack entirely (miss/dodge/parry), and a 55.6% chance to block the attack. This is what we'd call "unhittable" or "block capped." This occurs when your combined miss, dodge, parry, and block percentages add up to 102.4% (100% plus the 0.6% reduction to miss, dodge, parry, and block due to the boss's 3-level advantage).

It's also worth noting at this point that some special abilities that bosses use ignore sections of the table (for example, Baleroc's Inferno Blade can't miss and Decimation blade can't be blocked, and you'll still run into the occasional special attack that can't be dodged or parried). In those cases, you may find that the ability can hit even if you're "unhittable" to regular melee attacks.

Given the nature of the combat table, it's theoretically possible to push block off of the table by stacking more pure avoidance. Practically, this isn't possible because the gear to accomplish this doesn't (and won't, for encounter balance reasons) exist.

This tutorial has focused solely on incoming attacks from bosses, but the attack table system is also used for our offensive attacks. We'll discuss that in the next section.

Last edited by theckhd on Sun Sep 02, 2012 4:35 pm, edited 13 times in total.

Our melee attacks use a very similar attack table system that a boss's attacks do. However, our spells and special abilities (as of patch 3.0 anyway) use a slightly modified version of the attack table mechanic. A convenient way to describe the difference is by using the number of /rolls required to get a result; our melee attacks on a boss (as well as the boss's attacks on us) use a "one-roll" system, which is what's described in the previous section. Our spells and special abilities use a "two-roll" system (as discovered in April by testers at EJ [1][2]), which I'll describe in more detail later in this tutorial.

First, let's look at our auto-attacks and the "one-roll" system:

One-Roll MechanicsThe one-roll system only requires one roll to calculate the result of an attack. It treats avoids, crits and hits as separate entries on the attack table. Against a lvl 88 raid boss with no combat rating adjustments (i.e. 0 hit rating or expertise), our attacks have a 14% chance to be parried, 6.5% chance to be dodged, and 8% chance to miss. In addition, a lvl 88 boss has an inherent "melee crit suppression" of 4.8% [3], and against auto-attacks a "glancing blow" chance of 24% [4] (glancing blows do 75% damage to a raid boss). If we assume we have a 24.8% total chance to crit (to make the numbers easy), the attack table is constructed as follows:

The server does a /roll 100 for each auto-attack to determine the outcome. As you can see, we actually have a 28.5% chance to miss our attack entirely. This is where combat ratings come in. Through hit rating and expertise, we can reduce the chances for misses, dodges, and parries to make sure our attacks connect.

Similarly, it takes 30.0272 expertise rating for one expertise skill, which reduces dodges and parries by 0.25%. This conveniently works out to 120.1088 expertise rating for 1% dodge and parry suppression (4 expertise skill). This means that we need 26 expertise skill (781 rating) to remove dodges from the table, and 56 expertise skill (1682 rating) to remove parries from the table. Expertise is only half as effective after 26 rating, so despite being our best threat stat below the "soft-cap" of 26 expertise skill, it's not efficient to try and increase threat by pursuing extra expertise past 26 skill.

There's no way to remove glancing blows from the table, but since they only affect our auto-attacks and they still do damage (and thus proc seals), this is of little concern to us as tanks. It's a greater concern to melee dps because of its position on the attack table - it's possible to stack enough crit that regular hits are pushed off of the table. At this point, extra crit does nothing for melee auto-attacks until the player further reduces their chance to be dodged/missed (attacks from behind can't be parried).

Now that we've seen how the one-roll system works, let's look at the two-roll system. The two-roll system holds slightly greater importance since it determines how the bulk of our core abilities work.

Two-Roll MechanicsThe two-roll system requires two rolls to calculate the result of an attack. The first roll is performed on an attack table that solely determines whether the attack succeeds or fails (i.e hit or miss). The second roll determines whether a successful attack will be a regular hit or a critical strike. This is most easily demonstrated with an example. Let's look at a generic special ability that acts like a melee attack, again without any combat rating adjustments. The first attack table would look like this:

The game would roll on this table first to determine whether the attack hits or is avoided. If it connects (71.5% chance), the game will perform another roll to determine whether it's a hit or a critical strike:

Since a missed attack can never crit, this has an important fundamental implication on our overall critical strike chance. Statistically, our expected critical strike is reduced due to missed attacks. If our character sheet critical strike % is 24.8% (or 20% after suppression), we only expect to see (1-(miss+dodge+parry)/100)*20% = (1-0.285)*20% = 14.3% in our recount logs. That's a pretty noticeable reduction, and one of the major reasons that hit and expertise are valuable threat stats (especially for dps classes/specs). By reducing our chance to be missed, dodged, or parried, we make better use of our critical strike chance.

The other reason (and more important reason for us as tanks) that hit and expertise are important is that for an attack to proc a seal, it has to connect. Thus every miss, dodge, and parry we see is one fewer seal proc.

As an example, let's take Judgement. Judgement works like a special melee attack that cannot be dodged or parried. Thus, the first attack table for Judgement looks like:

This is one of the reasons that expertise isn't twice as effective as hit for total threat generation - several of our attacks cannot be dodged or parried, but can be missed. If you're curious about how each of our individual spells works, see the list further down in this guide.

Spells work exactly the same way, except that they can never be dodged or parried. In addition, the spell hit cap is 17% for a raid boss rather than 8%, though the conversion from hit rating to spell hit % is more forgiving at 102.4457 rating for each 1% hit. However, we gain 8% spell hit as protection from our talent specialization, which means we actually need less hit rating to cap spells than to cap melee attacks (9% spell miss after talents is 923 rating). This used to be an important issue for taunts, which are considered spells. Fortunately, as of 4.0.1 taunts are hardcoded to never miss, which means that we no longer care very much about the spell hit cap.

Last edited by theckhd on Thu Aug 04, 2011 10:28 am, edited 7 times in total.

Offensive abilities have different miss rates depending on the type of ability and target level. A boss is always considered level player+3, or 88 for a lvl 85 player. Here are the melee and spell miss chances for different level targets (assuming max weapon skill):

ExpertiseIt takes 30.0272 expertise rating for one expertise skill, which reduces dodges and parries by 0.25%. This conveniently works out to 120.1088 expertise rating for 1% dodge and parry suppression (4 expertise skill).

Note that expertise skill does not truncate, despite not showing decimals on the character sheet. Thus, every point of expertise rating gives you a benefit, even if you're only going from 10 to 10.1 expertise skill.

Note: Now that defense skill has been removed from the game, this mechanic should be entirely level-based. It's unclear what effect this has on the anecdote about Thorim, but it's probably not that important unless we see the same mechanic pop up in a Cataclysm encounter.

A crushing blow is an auto-attack that hits for 150% damage. It can only occur when an NPC attacks a player, and only if the NPC's weapon skill is 20 points greater than the player's current defense skill, capped at the level-maximum (400).

In practice, this means a crushing blow will only occur when tanking a mob that's 4 levels higher than you, making it irrelevant for end-game tanking in WotLK. However, evidence has shown that while under the effects of Thorim's Unbalancing Strike (which reduces total defense skill below the level-maximum of 400), his arena trash mobs can inflict crushing blows on players[8].

Crushing blows were a larger concern in the Burning Crusade, when a boss-level mob was able to crush a player (the differential was 10 points at that time). One of the selling points of a paladin tank in this era was that due to Holy Shield and the block mechanic, we were able to consistently push Crushing Blows off of the attack table.

A level 84 mob has a 15% chance to score a crushing blow on a lvl 80 player with 400 defense skill.

Last edited by theckhd on Wed Dec 15, 2010 8:20 am, edited 4 times in total.

This is a sexy guide thank you very much. I was thinking of this stuff just days ago.

One thing though; How are you determining the roll system on SoC? Once SoC procs does it go off a 2 roll system or are you counting the initial attack it procs off of a first roll? As to say, initial attack has a 75% chance to land, if it doesn't, SoC has a 100% miss rate as well. If it does it has a 100% hit rate = 2roll system. Or are you saying after the attack it proc off of hits, it continues onto SoC where SoC proc is determined by a 2 roll system by itself, and is that not a 3 roll system?

æ wrote:One thing though; How are you determining the roll system on SoC? Once SoC procs does it go off a 2 roll system or are you counting the initial attack it procs off of a first roll? As to say, initial attack has a 75% chance to land, if it doesn't, SoC has a 100% miss rate as well. If it does it has a 100% hit rate = 2roll system. Or are you saying after the attack it proc off of hits, it continues onto SoC where SoC proc is determined by a 2 roll system by itself, and is that not a 3 roll system?

When we say "one-roll" or "two-roll," we're referring to the number of rolls that a successful attack will generate to resolve fully. That means we only count rolls that directly determine something about that spell. So the auto-attack that procs SoC doesn't count towards SoC's total, because it is generated by the auto-attack, not by SoC.

In other words, it works like this:

Roll 1: Game rolls for auto-attack, using one-roll mechanics.

If the auto-attack connects, roll for SoC, using two-roll mechanics. If it doesn't, Roll 2 & 3 never happen.

Roll 2: Game rolls for SoC, to determine hit/miss/etc. If it hits, continue to roll 3. If not, Roll 3 never happens.Roll 3: SoC, to determine crit.

So if the attack connects, SoC is invoked and resolved using 2-roll mechanics. That doesn't make it a 3-roll system, because the SoC proc itself only ever generates 2 combat rolls. The game doesn't make Roll 2 on an empty combat table if the auto-attack misses, it simply doesn't generate that roll at all. So while it's true that it takes three rolls to fully compute a successful Seal of Command proc, only the last two are attributable to SoC. The first is attributable to auto-attack.

To put it another way: your example was correct, but your terminology was wrong. The first combat roll, while required for SoC to proc, would have happened anyway even if you weren't specced into SoC. So that roll isn't SoC's "fault," even though it does have an effect on whether the seal procs.

SoV DoT has this mechanic: the application (the proc basically) is now a melee attack, subject by being dodge/parryed/miss and on the 8% miss. The DoT itself cannot be resisted, not even partially.

theckhd wrote:Fuck no, we've seen what you do to guilds. Just imagine what you could do to an entire country. Just visiting the US might be enough to make the southern states try to secede again.

halabar wrote:Noo.. you don't realize the problem. Worldie was to negative guild breaking energy like Bolvar is to the Scourge. If Worldie is removed, than someone must pick up that mantle, otherwise that negative guild breaking energy will run rampant, destroying all the servers.

Might be my combat text not showing it properly then, i havent seen a single resist ever, but if logs show it i'm fine with that.

theckhd wrote:Fuck no, we've seen what you do to guilds. Just imagine what you could do to an entire country. Just visiting the US might be enough to make the southern states try to secede again.

halabar wrote:Noo.. you don't realize the problem. Worldie was to negative guild breaking energy like Bolvar is to the Scourge. If Worldie is removed, than someone must pick up that mantle, otherwise that negative guild breaking energy will run rampant, destroying all the servers.

I may add a brief paragraph to mention Crushing Blows just for the sake of completeness. I left them out of the initial version of the guide since they aren't relevant to end-game tanking anymore. But it might be nice to have it in there just for posterity's sake.

Just a clarification: Correct me if I am wrong, but Thorim's Unbalancing strike itself would not count as a crushing blow. Any attack taken when under the effects of the secondary debuff would be subject to crushing blows as your defense is reduced by 200 as an effect of the strike's debuff.

Dakiros wrote:Hear that sound? Its Wrathy breaking Wowhead and Wordpress while he quickly comes up with the Rival set.

Neither of those are true, in fact. Lythac's wording was subtle, but correct:

Lythac wrote:With the crushing blows, mob does not need to be 4 levels above you, crushing blows occur when boss weapon skill is greater than your base def skill by at least 16.

(emphasis mine).

Thorim's debuff does not change your base defense skill.

The test should be fairly easy though: find a single instance of Thorim performing a crushing blow on a tank. If you can't, then it's base defense skill that matters, not net defense skill.

I need to do a quick revision of this so I can get it posted in the Guides section of the site. I plan on adding most of the suggestions made so far. I'll try and post a changelog so people can more easily pick out errors in the new text.