'Chance for x' Enhancements

[jemal999]

I'm not sure where to ask so this seemed the best board.

Recently hit 50 and started looking into sets, noticed a lot have "chance to do x", like "chance to stun, chance to deal extra damage, etc".  They dont include what the chance is but most DO say something like 'this will occur x times per minute'..

Does that mean that the chance of it occurring Is based on the cooldown of the power?

Ie if it says 'will occur 6 times per minute' and I slot it on a power with a 10+ second recharge would it have a 100% chance of occurring?

 

If not then how do they work and what does the 'x times per minute' mean?

[Adeon Hawkwood]

The formula for procs per minute is a bit complex but you've got the basic theory correct. A few notes. First the proc chance is capped at 90%. Secondly the recharge used is the modified recharge, not base (it definitely includes recharge enhancements, I'm not sure about global recharge buffs, I've heard conflicting reports). Thirdly AoE powers use a modified formulae that adjusts the proc chance based on the area of the AoE.

[EmperorSteele]

If you want one point of anecdotal evidence...

 

My Mind/Kin has a "Chance to stun" and a "Chance for damage" proc in Transference, the target-based heal. Now I don't heal very often, but when I do, these procs rarely go off. Maybe one time in 3 at best.

 

I have "Chance for stun" in Terrify, the cone Damage/Fear power. This will occasionally go off on at least one foe, sometimes up to 3 (out of a max of 16 hit). Though it doesn't last very long, and being mag 2, only affects LTs and minions.

 

I also have a "Chance for +2 Mag hold" in Total Domination, the AoE Hold. When it goes off, any enemy who's affected will get an electric field around them. And without fail, this field will appear on about 90% of the foes in range of my hold.

 

So the whole "based on recharge of the power" sounds legit, as those powers have an enhanced recharge of a few seconds, ~30 seconds, and ~2 minutes respectively.