I've seen a lot of questions and false information about character stats thrown around on these boards, so I'm making this post to provide a resource for everyone for how exactly all of the stats work. Note that this guide is sorcerer-specific, I won't be covering Assassin benefits here (the only real differences, for those wondering, are that Willpower also affects their melee attacks, they need Accuracy rating, and for tanking, Defense, Shield, and Absorption).

First, some background. Nearly every stat in the game follows a diminishing returns curve. For those mathematically-oriented, these curves asymptotically approach a certain limiting value.

For those not so mathematically inclined, that basically means that the benefit you gain from adding a certain amount more of that stat gets smaller and smaller the more of it you have, with a certain "ceiling" it can never exceed. For example, crit rating limits to 30%. Thus the more and more crit rating you add to your character, the closer and closer you get to that 30% bonus, but you can never actually reach it.

Also, note that the benefit from each stat is on a separate DR curve, and raw percentage benefits (such as from abilities) have no effect on any DR curves (they are additive on top of them instead). Thus how much Willpower you have, for example, has no bearing on how much benefit you get from X crit rating, and vice versa. This doesn't imply that the

*DPS value* of the stats are independent, but that's another discussion entirely.

__Willpower__
Increases force damage, healing, and critical effect chance. Each points provides 0.20 Force Bonus Damage and 0.14 Force Bonus Healing. Critical effect chance benefit scales slowly and limits to 30%.

__Force Power__
Increases force damage and healing at a slightly higher rate than Willpower. Each point provides 0.23 Force Bonus Damage and 0.17 Force Bonus Healing.

__Power__
Identical to Force Power for Sorcerers. Each point provides 0.23 Force Bonus Damage and 0.17 Force Bonus Healing. Also increases melee, ranged, and tech at the same rate.

__Critical Rating__
Increases critical effect chance with all damage and healing abilities. Benefit scales moderately and limits to 30%.

__Surge Rating__
Increases the bonus damage or healing from a critical effect. Additive with the base 50% critical multiplier. Benefit scales rapidly and limits to 30%.

__Alacrity Rating__
Reduces the cast time of casted and channeled abilities. Additionally reduces the length of the global cooldown for those ability if their cast or channel time drops below 1.5 seconds. Does not reduce the GCD for instant abilities, nor for cast/channeled ones if their final cast time remains above 1.5 seconds. Additive with multiple Alacrity sources. New Cast Time = Original Cast Time * (1 - Alacrity%). Scales moderately and limits to 30%

__Accuracy Rating__*

Reduces chance to miss against a target, and once miss chance is 0%, begins to negate the target's Defense or Resistance. Boss targets are believed at this time to have zero innate resistance, and force attacks have a base accuracy of 100% against all targets. Thus,

__this stat is worthless for Sorcerers in PvE__. In PvP, no gear stat gives resistance, and only limited abilities do. Thus it is generally worthless against most targets and not worth gearing for. Scales moderately and limits to 30%.

__Shield Rating__*

Increases your chances of "blocking" and attack with your shield generator. Referred to as

*Glance Rating* on TORhead. Requires a shield generator in offhand, and thus is useless to Sorcerers. Scales moderately quickly and limits to 50%.

__Absorption Rating__*

Increases the damage absorbed by a successful shield "block". Does

*not* increase the damage absorbed by Static Barrier or similar absorption buffs/abilities. Requires a shield generator in offhand, and thus is useless to Sorcerers. Scales rapidly and limits to 50%.

__Defense Rating__*

Increases your chance to avoid melee and ranged attacks. Dodge, parry, and a few other terms are all manifestations of this stat. Sorcerer base defense is 10%. Has no effect on Force or Tech attacks. Generally useless to Sorcerers. Scales moderately and limits to 30%.

__Expertise Rating__
PvP-only stat. Increases your damage and healing done to other players and decreases the damage you take from other players. Healing is increased by "ignoring" part of the Trauma buff that is automatically applied when you enter PvP combat, and thus scales somewhat better in actual effect than the percentage displayed on the character sheet. The damage bonus scale moderately and limits to 50%, while the trauma ignore scales slowly and limits to 30%.

The DR portion is now (as of 1.2) calculated directly off of the damage portion, and is equal to 1 - 1 / (1 + DamageBoost%). The net effect of this change to DR is that any character attacking another character with the same amount of expertise will deal the same amount of damage they would deal if both they and the target were at 0 expertise. Previously, the DR portion scaled somewhat better, so, for example, a 1000 Expertise character attacking another 1000 expertise character would deal noticeably less damage than if both characters were at 0 expertise.

***NOTE:** Gear with these stats, while worthless to Sorcerers directly, may be of some benefit if equipped to certain of your companions instead.
I've also made this handy graph showing the scaling of all of the stats. Left graph shows the total benefit of the stat based on how much you have, while the right graph shows the benefit of the next 10% of that stat based on how much you already have. Remember, separate stats have no effect on the benefits each grants, even if they give the same bonus (such as Crit and Willpower), and percentage benefits from skills and abilities are applied additively after the rating conversion is applied.

The first graph shows scaling from 0 to 1000 rating, the second from 0 to 2500. The third graph shows the percentage of the limiting cap obtained at each rating level. This is important, since the benefit rating gives you is proportional to how much of the cap you have remaining. ie. if you are at 60% of the cap, the rating will be providing you with 40% of the benefit it did when you had 0 of that rating). The fourth graph is simply a comparison of 1.1.5 to 1.2 values for Expertise.

0-1000 Rating Graph
0-2500 Rating Graph
Percentage of Cap Graph
1.1.5 to 1.2 Expertise Comparison Graph
If you're interested in more specifics on how the stats work, what the formulas look like, and how we came up with them, check out this post over on sithwarrior.com (warning: it's a bit mathy):

http://mmo-mechanics.com/swtor/forum...R-formula-list