Thank you, I see now, so you basically have to go through two checks before your hit may connect.
I'm not saying it's how it works, because both WoW and FFXIV will display "Hit", "Miss" or "Evade". (single roll vs multi-roll)
WoW is an example of a game where you determine the result with a single roll, which cause some problems with their system with every expansion, basically tanks reaching a point where their evasion is high enough to become unhittable. (They "fixed" it with Diminishing returns, which only slows the issue down)
FFXI also dealt with Accuracy vs Evasion the same way (single roll), but added other rolls for parry and shield. (It was bundling accuracy with evasion in 1 roll. Base hit was 75%, every 2 accuracy was +1%, every 2 evasion for the mob was -1%)
Which game's footsteps does FFXIV follow? Single-roll? 4 rolls per hit? (accuracy, then evasion, then parry, then shield) Nobody really knows right now.
In a nutshell, though, something that reduces enemy's accuracy will not increase EVADES in XIV. You need to increase your evasion for that to happen. (Absorb Evasion, Featherstep, Evasion on gear, etc.)
I.e. we know it can't work the same way XI does it, because XI couldn't distinguish evasion from misses.
Edit: To add to the problem; lowering a mob's accuracy, depending on the situation, might help reduce damage, but would also lower the number of hits you have to evade against, meaning that you'd get fewer haymakers, which means lower damage, effectively making -Accuracy debuff counter-productive. (The same way the "slow" spell reduce gladiator's damage output quite drastically by killing their phalanx spam). Obviously, those abilities (concussion blow, slow, etc.) remain useful on a purely defensive point of view; it just doesn't double-tap by also providing extra damage as one would expect. Edited, Sep 14th 2010 5:15pm by Docent42