This is probably a fairly easy question to answer but what is the actual impact of this skill? 6% less chance to be crit by melee and ranged attacks is taken into account on every hit (a very nice mitigation talent) or only when the crit check has scored a hit (and then there is a 6% chance that crit is nullified). Interesting to see how this interacts with resilience, too. Thanks in advance for comments.

From what I understand, it acts in the same was as resilience, but a flat % rather than the rating system.

ie: Warrior has 25% crit, no +hit. Works out at 25% crit, 71% hit, 4% miss.
With Elemental Shields, that becomes 19% crit, 77% hit, 4% miss.

Assuming 100% = 1 hit, then the warrior has 121% damage, but after Shields this is 115%.