I have just realized that damage resist mods does not give the stated resitance boost for some damage types, NOT counting in stacking penalty.

Lets say with an Adaptive invul2, which in the description says to give 30% bonus to all damage types.
When you switch it on in space, with only one of it and no other resist mods or rigs, it gives 30% resist bonus only to EM, and less and less towards Explosive, giving only about 15% on Explosive.

Is this the way it's supposed to be? Then what is going on?

Somebody please explain to me :S

Resist modules are not stacking penalized. However, resists added to a certain damage type are reduced by the current resist percentage. Otherwise, it would be hilariously easy to get resists beyond 100% on tech 2 and 3 ships.

So adding a 30% bonus on top of a 25% resist will get you .30*(1-.25)+.30 = .525 = 52.5% resist, not 55%.

Also, inb4 moved to ships and modules.

Thanks for all the answers, so that was whats going on :O

EVE math is really confusing at some parts :S

Sooner or later you'll realize it actually makes way more sense than the math in any other game. You just need to remember that everything multiplies.

Sooner or later you'll realize it actually makes way more sense than the math in any other game. You just need to remember that everything multiplies.

Resists are penalized, unless they're explicitly stated not to. Like the damage control module.

Go with signature and speed tank.

although the mod description says 'penalty', i think resist mods are really more like diminishing returns, rather than the stacking penalty mechanic? the damage control is just additive to the resist rather than multiplicative?

Diminishing returns is exactly what it is. Adding a new mod will never make you worse off in that particular area. Damage control is not additive, as nearly nothing is actually additive. The way it works is that all stacking penalized mods go on "a stack," sorted by the strongest first. Then diminishing returns apply starting from the second effect (not necessarily module) on the stack. Non-stacking penalized mods are not on the stack, and apply their full bonus. The exception is the damage control and reactive armor hardener, which are both not stacking penalized, but when used together, are considered stacked together, with the weaker bonus getting the 87% penalty. Note that things on the stack are effects, not a module itself.

although the mod description says 'penalty', i think resist mods are really more like diminishing returns, rather than the stacking penalty mechanic? the damage control is just additive to the resist rather than multiplicative?

There is the native penalty involved that this thread covered and the arbitrary penalty added to curb multiplier stacking. Wasn't really needed for resists, but they did it anyway.

Resists are double penalized, nothing else gets that treatment.

although the mod description says 'penalty', i think resist mods are really more like diminishing returns, rather than the stacking penalty mechanic? the damage control is just additive to the resist rather than multiplicative?

It's because, behind the scenes, they apply their damage reduction in different ways.

you have resists, from the regular hardeners, plates, etc.

And you have a damage resonance from the damage control and the reactive armour hardener.

so they get stuck in stacks based on that, then the penalties are applies, per stack.

Diminishing returns is exactly what it is. Adding a new mod will never make you worse off in that particular area. Damage control is not additive, as nearly nothing is actually additive. The way it works is that all stacking penalized mods go on "a stack," sorted by the strongest first. Then diminishing returns apply starting from the second effect (not necessarily module) on the stack. Non-stacking penalized mods are not on the stack, and apply their full bonus. The exception is the damage control and reactive armor hardener, which are both not stacking penalized, but when used together, are considered stacked together, with the weaker bonus getting the 87% penalty. Note that things on the stack are effects, not a module itself.

I just throw stuff on and see what happens.

It's because, behind the scenes, they apply their damage reduction in different ways.