Determination. Per Dervy's blog at: https://dervyxiv.wordpress.com/2015/...ghts/#more-162

Summoner w/ Garuda – No book smacking:

WD: 11.602
INT: 1.000
DET: 0.137
CRT: 0.147
SS: 0.119

Summoner w/ Ifrit – No Book smacking:

WD: 11.602
INT: 1.000
DET: 0.136
CRT: 0.147
SS: 0.115

Also of note he does his testing on single target. Any AOE or double tapping moves it more towards det.