Stats and Attributes in World of Warcraft - Explanations and Analysis

Stamina is the stat responsible for how many hit points your character has. Stamina converts to hit points for all classes, mobs, and NPCs at a rate of 1:10. In other words, one point of Stamina gives 10 hit points. There are many talents and abilities that will increase a players stamina by a percentage or flat value, but there are none that change the Stamina:HP conversion. Stamina is found on Blue Gems.

Agility is a melee-oriented stat that gives bonuses in the way of critical strike rating, attack power, dodge, and armor. Agility is a primary DPS stat for Hunters, Rogues, Feral Druids, and Enhancement Shamans. It is a secondary DPS stat for Warriors, Death Knights, and Retribution Paladins. It is a primary tanking stat for Feral Bear Druids (because of their main reliance on dodge and armor), and a secondary tanking stat for Death Knights, Protection Warriors and Protection Paladins. Note that Agility will never be found on Plate Tanking items, but occasionally shows up on non-armor pieces like Rings and Necks. As a general rule, if Agility is not listed as a primary stat for your class and spec there is no need to seek out gear, enchants, or gems that use it. Agility is found on red gems.

Strength is one of the standard stats, and most often found on Plate armor items. It is very rarely found on Rings, Necklaces, or Cloaks, and only sometimes found on Weapons. Strength has different uses depending on class and spec, but it's main aspect is granting attack power to Warriors, Death Knights, Druids, and Paladins at the rate of 2:1. In other words every point of Strength gives two points of Attack Power.

For classes that can Block (mainly just Warriors and Paladins) Strength gives block value at a 2:1 rate (2 points of STR = 1 point of Block Value). Death Knights gain Parry Rating from Strength at a 4:1 rate (4 points of STR = 1 point of parry rating).

Strength is found on Red Gems.