You can only dodge Ranged and Melee Attacks. Force and Tech attacks cannot be dodged. When dealing damage, White damage represents Melee/Ranged attacks, while Yellow represents Tech/Force.
The ability is mediocre, but becomes really useful as an Operative as they get a secondary effect, removing all hostile removeable effects.

I'm very curious just as the what it is possible to dodge. I know almost all of the Bounty Hunter's abilities penetrate this, as do all of a Scoundrels main attacks. It seems like purely a counter-measure against Snipers, and the under populated, non-force using classes white damage, which is a very insignificant amount of abilities (apart from, as mentioned before, the majority of Sniper/Gunslinger's main attacks).
In other words, this is crap except for the benefits tacked on by talents, and defeating Snipers/Gunslingers.