Strategy Guides

Ultimate Guide to Aggro

1) Definitions
We define "aggro" to be who the mob is attacking. We define "threat" to be a numeric value that each mob has towards each player on it's hate list. Note, as we shall soon see, even for a normal mob, the target who has aggro is not necessarily the player on it's threat list with the most threat.
We define arbitrarily that 1 point of unmodified damage gives 1 point of threat.

Summary:
Aggro who the mob is attacking. Threat is your position on the monsters blacklist threat is a 1:1 ratio so if you hit 100 damage (not including modifiers spells etc) you receive 100 threat.
2) Gaining aggro on a mob

Suppose a mob is attacking player 1. In order for the mob to switch to player 2, he must do more than just exceed the threat of player 1. If he is in melee range of the mob, he will draw aggro when he exceeds 110% of player 1's threat. If he is outside melee range of the mob, he will draw aggro when he exceeds 130% of player 1's threat.
E.g. mob is attacking player x. x does 100 damage to mob, then stops. Player y starts hitting the mob. The mob will start attacking y when y does over 110 damage.
Proof: this is easy to demonstrate. Get two players both doing autoattack on a mob (not warriors of rogues; we'll see later they complicate things). Have player 1 do a certain amount of damage, then stop. Have player 2 keep attacking till he gets aggro. You have an upper and lower bound on the threat required to get aggro - 1 attack before he got aggro was not enough, but the attack that he got aggro was at least enough. With low damage attacks (i.e. fists only), you will get a very good value of 10%. Testing for the non-melee range value is the same. Just replace it with a low damage ability such as a low level wand.
If player 2 has exceeded 110% threat but not 130% threat, they will draw aggro immediately if they do a threat-generating ability within melee range of the mob, but proximity alone will not cause the mob to shift to them.
This is only a description of the normal mob targeting. Obviously there are mobs who will attack secondary targets with special abilities, ignoring their current threat / aggro.

Summary:
To get aggro you must gain more threat than the monsters current target if you are meleeing the mob you need to gain 110% more threat if your ranged it has to be 130% more threat so if the player being aggroed has 100 threat you need to do 110 combat damage or 130 ranged damage

3) Threat modifiers from Warrior Stances
In Battle Stance and Berserker Stance, all threat from a Warrior is multiplied by 80%. In defensive stance, the multiplier is 130%. With Defiance, it is 145%.
Proof: a simple modification of the above proof. Get a warrior to do, say, 1000 damage in defensive stance, without defiance. Get a non-warrior to take aggro with white damage. You will find it does not happen before 1430 damage. The warrior's 1000 damage caused 1300 threat in defensive stance, and the 10% barrier means you need more than 1430 to gain aggro.

Summary:
When in battle and berserker stance warriors have there threat multiplied by 80% in defensive its 130% and if the warrior uses Defiance its 145%
i.e. in battle/berserk stance 100 damage makes 8000 threat in defensive its
1300

4) Threat does not decay
Threat never, ever decays. Here is test . Warrior does 83 damage on mob in battle stance, gains aggro. From above, we know it will take more than 83 * 0.8 * 1.1 = 73.04 threat to gain aggro. Warrior waits for 5 minutes getting beat on. Then mage starts attacking slowly. Mage does 73 damage, but does not gain aggro! Mage does another 2 damage, and does gain aggro. From the warrior's initial hit to losing aggro, the time taken was 496 seconds.
As an upper bound, assume maximal threat decay. i.e. the mage only needed 73.000000001 threat to gain aggro. Then the warrior's threat had decayed to 66.36363636, from 66.4. This means he went down to 99.945% threat in 496 seconds.
At this maximal rate of hate decay, the time taken for the warrior's threat to decay to 90% of the original value would be 26.5 hours. In fact, if a warrior logged in as soon as the came online after the weekly reset and hit a mob, his threat would not decay to 50% before the server reset next week. I think this is enough to rule out threat decay.

Summary:
Just disproving a old legend that threat levels dropped and was reset by the realm restart

5) Threat values for some warrior abilities Updated Jan 20
The following list is not exhaustive, but includes all the major tanking abilities.
Note: the following values are given in raw terms. In reality the warrior must have either a 1.3 or 0.8 or 1.45 modifier on these, depending on his stance and talents.
Note: * All abilities do not include threat generated by their damage. This will be discussed more later.
Sunder: 261 (260.95 - 261.15)
Heroic Strike*: 145 (143.9 - 148.8)
Revenge*: 315 (313.9 - 318.3)
Revenge Stun: 25 (23.4 - 29.1)
Shield Bash*: 180 (175.4 - 180.3)
Shield Slam*: ?? 250 (estimated)
Shield Block: 0 (0 - 0. Can be higher - more on this later)
Thunder Clap*: 130 (126.9 - 134.8)
Demo Shout: 43 (42.8 - 43.8)

Note that debuffs associated with abilities are not connected to the threat they generate. Demoralizing shout generates the same amount of threat whether the debuff is on or not. Sunder armor generates the same threat after 5 debuffs are on as when there are 0.