(This is from the wiki Hyperlab guide, not my own research)

Provocation:

This device causes the ship with the provocation device equipped to be targetted with higher likelihood by random skills (RF, CFF). The initial device causes the ship to be targeted 50% more, first upgrade 100% more, second upgrade 150% more, and final upgrade 200% more. What this means is that if (for example, with a max-level device) there are five fleets, two tanks with the device equipped and three DPS without the device equipped, then the device will function as follows. The DPS will remain with their 100% likehood, the two DPS at an additional 200% for a total of 300% likelihood. That means there is a total of 900% to be distributed between the five ships. The DPS are at 100%/900%, so 11% likehood of being hit each, and the tanks are at 300%/900%, so 33% likelihood of being hit each. This means that without provocation devices, you had a 60% chance of taking a hit on a DPS; now, with provocation devices equipped, you have a 33% chance of taking a hit on a DPS.

So say you have 5 fleets with no device, 100% each. # are your EVA fleets

100 100 100 100 #100 = 500 total > 1/5 chance to hit a single EVA fleet = 20 => 80% chance hit a DPS

And the same goes for the following examples:

100 100 100 100 #300 = 700 > 3/7 = 43 => 57% to hit any DPS fleet

100 100 100 #300 #300 = 900 > 6/9 = 66.66 => 33% to hit any DPS fleet

100 100 #300 #300 #300 = 1100 9/11= 82 => 18% to hit any DPS fleet