User blog comment:Mich, Michele & Kuhla/Analysis: An In-depth look into Mechanics/@comment-25971902-20150612004912

dont overthink it. "atk down" means attack down, not damage. who would think attack means damage? no, attack means attack, damage means damage, defense means defense, half damage means half damage. units have 4 stats: hp attack, defense, recovery. Also, if you want to test stuff for fixed damage(like % mitigation), the jelly dungeon(http://bravefrontierglobal.wikia.com/wiki/Cordelica:Bonus?action=render) is the best place. he hits x (i forgot the number) times for 2000 total damage. used this place to figure out that Bargus mitigates exactly 25% damage.