Defense is a tanking stat designed to give tanks of all classes the things they need to avoid and survive physical hits. It has many functions. Each point of Defense skill (not rating) adds a .04% chance to be missed by the target, and to dodge, block, and parry - meaning for every 25 Defense skill you have you increase the miss rate of your opponent by 1% and give yourself a 1% each chance to dodge, block, and parry an incoming attack. At level 80, it takes 4.92 Defense Rating to make 1 Defense Skill.
Beyond that, Defense also reduces a tank’s chance to be critically hit, and if he stacks enough Defense he can become totally uncrittable. At level 80 a Defense skill of 540 is required to eliminate your chance to be critically hit by any mob or raid boss. For Heroic level dungeons, a Defense skill of 535 is all that is needed. Raid bosses have a 5.6% chance to critically strike a level 80 player. Druids who take the Survival of the Fittest talent get a 6% chance to not be critically hit, making Bear Tanks naturally crit-immune.
Defense is found on Yellow Gems.
Dodge is one of the three avoidance mechanics in the game. Dodge Rating, usually expressed as a percentage, is your chance to dodge an incoming melee attack (do not confuse Dodging with Missing - they’re unrelated). When a player dodges an incoming attack, the entire attack is avoided. Players cannot dodge attacks coming from behind them, but mobs can. Additionally, a player cannot dodge if they are stunned. Dodge percentages are derived from three things: Defense Skill, Dodge Rating, and Agility. As mentioned above, 1 Defense skill gives a 0.04% chance to dodge an attack, and the dodge derived from Agility is purely dependent on class, spec, and level.
Dodge is a complex mechanic because it is subject to diminishing returns. This means that the higher your dodge chance gets, the more points of Dodge Rating you’ll need to increase it further. That said, there are two kinds of Dodge - Diminished, and Undiminished. Undiminished Dodge doesn’t trigger Diminishing Returns, and is therefore preferable. Undiminished Dodge is dodge from your class' base dodge chance, dodge from Talents (like Anticipation), and Dodge Derived from your base Agility. Dodge from Dodge Rating, Dodge derived from Agility from gear and buffs, and Dodge derived from Defense is all subject to Diminishing Returns.
Dodge is found on red gems.
Parry is very similar to dodge, in that it gives you a percentage chance to completely avoid an incoming melee attack, from the front only. Parry is not a skill that all classes have, unlike dodge, however. Warriors, Hunters, Paladins, Rogues, and Death Knights learn the Parry skill early on. Enhancement Shamans can take the Spirit Weapons talent which, in addition to other things, gives them the ability to Parry. Parry is derived from Defense (0.04% Parry per 1 point of Defense) and Parry Rating. Death Knights are the only class that gains Parry from Strength, at the rate of 4 Defense per 1 point of Parry Rating. Some classes can increase their chance to Parry with talents. Like Dodge, Parry is also subject to diminishing returns, though it has been stated time and time again from the developers that “Parry still diminishes more quickly than Dodge”, effectively making 10 points of Dodge rating more valuable than 10 points of Parry rating, in the long run (from an Avoidance point of view).
However, from a Threat Generation point of view, Parry can arguably be better. This is because of a mechanic called Parry Haste. When a player (or mob) Parries an attack, their swing timer is reset. So if you’re using a 2.0 speed weapon, have just swung it and .1 seconds later Parry an incoming attack, you skip the rest of the 1.8 seconds left on the swing timer and swing again immediately. High Parry chance not only helps you avoid attacks, it also helps you hit more often. On the flip side, this mechanic can be bad for tanks because bosses also get Parry Haste, meaning they can hit you for massive amounts back to back. Read about Expertise in the guide to Offensive stats to learn how to avoid Parry Haste on bosses.
Parry is found on red gems.
Block is considered an avoidance mechanic for tanks, but isn’t as impressive as Parry of Dodge because it doesn’t avoid an entire attack - just portions of it. Block, naturally, only works with classes that use shields. This makes it primarily the concern of Tanking Paladins and Warriors. Block rating was once a very valuable stat for these tanking classes, but since the effective removal of Crushing Blows (in Wrath) it is far less desirable. Block chance is derived from Block Rating and Defense.
The amount of damage mitigated by a blocked attack is based on the players Block Value. Block Value is derived from Strength for Warriors and Paladins, and is found on armor and shields. To some extent, Block Value also helps with threat generation. The damage done by a Warrior’s Shield Slam and a Paladin’s Shield of Righteousness is dependent upon their block value. These abilities are often used to generate a large amount of threat quickly, but are less effective if the player has low Block Value.
Armor is the system by which WoW determines how much of a melee attack will be mitigated. Armor is largely based on your AC (armor class) - Cloth, Leather, Mail, or Plate. Armor tends to be passively found on armor items, like head, shoulders, legs, etc. but not on other pieces like trinkets, rings, and necklaces. There are some rings, necks, etc. that do have armor, and these pieces are generally intended for tanks of all classes. It used to be that these were considered Bear Druid only items, but “bonus armor” no longer scales with Bear Form, or Frost Presence for that matter. Armor is also derived from Agility, and the formula for determining your Armor is: Armor = 2 * Agility+ Gear Armor (armor value found on gear equipped) + Magic Armor (armor value from magic abilities, such as Inner Fire). If you hover over your Armor value on your character pane you will see the percentage of physical damage mitigated by your current Armor.
Resilience is considered to be a PvP only stat, and was added in The Burning Crusade to balance out the damage done in Arenas. Apparently the scaling of how much damage players can do versus how much damage they can take has not been equal throughout the lifetime of the game. Resilience has also been reworked a few times. Initially all it did was reduce a players chance to be critically hit. Then, it was changed to also reduce the damage taken from DoTs. Now, resilience has the following usages.
1% of Resilience:
- Reduces your chance to be critically hit by 1%
- Reduces the damage done by critical hits by 2.2%
- Reduces the damage done by DoTs by 1%
- Reduces the amount of mana drained or burned by mana draining effects by 2.2%
Players have no base resilience, so all resilience is obtained through pure resilience rating. Gear with resilience is only found as PvP related rewards - You will never see an item drop in a raid with resilience on it. Technically, a PvE tank could argue that it is easier to reach 5.6% resilience and become crit-immune than it is to achieve the same thing through 540 Defense - and, he’s right. However, Resilience gear rarely, if ever, has the other stats tanks need, like Dodge, Parry, Block, or Expertise - Not to mention that Defense also adds to Dodge, Block, and Parry chance. In extreme circumstances, a player can combine Resilience and Defense to become crit-immune for PvE content. The damage reduction from resilience for critical strikes caps out at 33%, or 1414.5 Resilience at level 80. However, there is no cap to how much resilience can be stacked to reduce critical hit chance or DoT damage. Resilience can be found on Yellow gems.
Mana Per 5 Seconds (MP5)
Mana Per 5 Seconds (MP5) isn’t a defensive stat, per se, but it doesn’t fall into any other category either. MP5 is pure mana regeneration. There is nothing fancy about it. MP5 completely ignores the FSR (Five Second Rule) and has the same effect in combat, out of combat, while casting, or while not casting. MP5 is wonderful for healers, but fairly useless for all other casters who don’t really run into mana regeneration problems. MP5 is most often found on gear for Restoration Shamans and Holy Paladins, but often finds it’s way to cloth for the benefit of both Discipline and Holy Priests. MP5 on the character pane is expressed “while casting” and “not while casting”. While casting MP5 is derived from Spirit and relies on talents that allow mana regeneration to continue while casting. Intellect can effect this amount as well, but that is better explained in this World of Warcraft Core Attributes Guide.
Magic Resistance is a defensive mechanic that decreases the damage dealt by incoming spells. Magic Resistance also reduces the chance for a non damage spell, such as a secondary effect or debuff (Frost Nova, Vampiric Embrace, etc) will land. Magic Resistance follows the five main schools of magic: Fire (FR), Frost (FrR), Nature (NR), Arcane (AR), and Shadow (SR). While Holy is it’s own magic school, there is no associated resistance for it.
Value ranges of the various types of magic resistances are used to determine what percentage of an incoming direct damage spell will be mitigated. If your magic resistance is even one point off from being in the next “tier”, you will not receive the extra benefit. At level 80, the following table is used:
0-82 Resistance = 0% Mitigation
83-165 = 15%
166-248 = 30%
249-331 = 45%
332-414 = 60%
415 and above = 75%
415 is the magic resistance cap, because you can never resist more than 75% of the damage from a spell.
Magic Resistance is primarily used in PvE, though even then very rarely. Normal resistance buffs, like Mark of the Wild or Prayer of Shadow Protection are often used by default in raids, and many races have a small amount of built in resistance. Some boss fights, however, are made much easier if every player wears a few armor pieces with Resistance on them. It is completely possible to kill Sapphiron in Naxxramas without anyone wearing a single point of Frost Resistance, but it makes life so much easier on your healers if everyone wears at least some - even the full 415 (this is especially true for the tank). In the same manner, Hodir in Ulduar can be done without the entire raid wearing Frost Resistance, but the tank usually needs to wear at least some. If the whole raid wears Frost Resistance gear the fight is much easier.
This post is part of the series: Ultimate Guide to Stats and Attributes in World of Warcraft
A discussion of all of the different stats and attributes found in the game World of Warcraft. We look at how core stats like Agility relate to Attack Power, how Magic Resistance really works, just how much Defense a tank needs, and so much more.
- Stats and Attributes in World of Warcraft - Explanations and Analysis
- Ultimate Guide to Stats and Attributes in World of Warcraft - Offensive Stats Breakdown
- Ultimate Guide to Stats and Attributes in World of Warcraft - Defensive Stat Breakdown
- World of Warcraft Cataclysm Stats and Attributes Changes