We asked the devs for a short explanation of Attack Power and Defense in relation to Agility and Strength. The following should be of some help to those wondering e.g. whether their new +x Attack Power weapon is better than their old +y Strength / +z Agility one. Agility - Increases Armor Class by 2 for every point of AGI. - Increases the chance of a critical hit with melee and ranged attacks. The amount of the increase is dependant on both class and level. For most level 60 character classes, approximately 20 points of AGI will increase your critical hit chance by approximately 1%. Rogues require 29 AGI for an additional 1% critical hit chance, and Hunters require 53 AGI for an additional 1% critical hit chance, but both of these classes also gain attack power from agility and the items available to them typically have much higher amounts of AGI. - Increases the chance to dodge an attack. The amount increased is dependant on both class and level. For most level 60 character classes, approximately 20 points of AGI will increase your chance to dodge by approximately 1%. Rogues only require 14.5 AGI for an additional 1% dodge chance. Hunters require 26.5 AGI for an additional 1% dodge chance, but Hunters typically have a high amount of agility, as well as an Aspect spell that further increases their chance to dodge attacks. Defense - Increases the chance of being missed by an attack. - Increases the chance to dodge, parry, and block. - Decreases the chance of being affected by a critical hit. - Decreases the chance of being affected by a "crushing blow". Creatures that are higher level than your character can land crushing blows that deal increased melee damage. The chance of a crushing blow increases as the level difference between you and the opposing creature increases. Players never deal "crushing blows", only creatures. Attack Power - Attack power increases your base melee DPS by 1 for every 14 attack power. - Strength increases your melee attack power by 2, except for rogues and Hunters. Rogues and Hunters gain 1 attack power per point of Strength, and 1 per point of Agility.

part 1 The way WoW calculates crit rate is over ALL attacks. Crit rate is not based on hits only. In other words, if you have a 5% crit rate, that 5% chance includes misses. All crit rate adjusting abilities, items, and talents add the flat % to the base % crit rate. So if I have a 5% base crit rate and then use an item or talent that increases that crit rate (let's use Improved Backstab talent for example - +30% crit), my new crit with backstab is 35%. Regarding how defense decreases the rate of critical strikes, each point of defense that a target has over the attacker, the attacker loses 0.04% chance to crit. So, for example, if a level 60 Rogue is attacking a level 60 Warrior who has 25 defense, the rogue's crit rate will be decreased by 1%. part 2 +toHit items subtract from your miss%. So, ignoring all defensive actions (Block/Parry/Dodge/etc..) if I have 20% crit chance, 20% miss chance, and 60% hit chance and I equip an item that gives me +5% toHit and +5% crit, my stats become 25% crit, 15% miss chance, 60% hit chance. New hit chance = (Original hit%) + (toHit modifiers) - (crit modifiers) 60% + 5% - 5% = 60% New crit chance = (Original crit%) + (crit modifiers) 20% + 5% = 25% New miss chance - (Original miss%) - (toHit modifiers) 20% - 5% = 15%