Defense Chance (comes from Defense Rating) gives you a chance to completely avoid taking damage.Defense Rating only gives Defense Chance for melee/ranged damage, and none for force/tech damage.
Generally speaking, melee/ranged damage is basic attacks, force/tech damage is special attacks.
Note, while you’re stunned or knocked down, your Defense Chance is 0%.
The 2-roll system This game uses something called the ‘2-roll system’, the game uses this to calculate the damage you deal/receive (if any).
Note, some parts of this explanation is mostly or only applicable to Pv P combat.
Your Defense Chance basically reduces the attacker’s accuracy.
2 roll: if you do take damage, the game determines if you shield the attack or not, and if the attack is a crit.
For further explanation, check the end of the Theorycrafting section.
Damage Profiles The main consideration for determining the effectiveness of your stats, and the stat combination you should go for, is the ‘damage profile’ of a fight.
Damage Reduction (comes from Armor Rating, which depends on your Armorings and gear type, e.g.
light armor for Shadows) gives you a passive damage reduction for each damage type: Energy/Kinetic damage (most non-periodic damage is energy/kinetic) and Internal/Elemental damage (generally speaking, Do T damage is internal/elemental; melee/ranged attacks are never internal/elemental) Damage Reduction granted by Armor Rating only reduces the damage you take from Energy/Kinetic damage.
An attack is either shielded, a crit, or a normal hit; an attack can never be both shielded and a critical hit.