Resistance

Resistance is the ability to be less affected by something. In-game, resistance values are often consolidated into a single group in the stat block. Below, we establish certain contexts in order to explain it more clearly.

There are several types of resistances in the game:
 * Damage Resistance, which reduces the amount of damage taken.
 * Stasis Resistance, which reduces the potency of the Stasis status effect.
 * Weapon Disruption Resistance, which reduces the effectiveness of the Weapon Disrupted status effect.
 * Counter Tech, which reduces the counter for Chain, Piercing and/or Ricochet weapons.

Damage Resistance
Damage Resistance reduces the amount of damage taken by the specified proportion. In the case of equipped items, the subject on which the resistance is applied depends on the source:
 * Resistors and status effects apply resistance to the ship or module, as well as any equipped armor and ablative armor. Fleet Commander bonuses that do not have a health component also follow this rule.
 * All other sources only apply resistance to the health contributed by itself.

It is worth noting that while shields and screens have resistances independent of that of the parent ship or module, ablative armor inherits the final resistance of the parent.

Resistance comes in two forms:
 * 1) Resistance against a damage type, which reduces damage taken from that damage type, as well as Nebula Fields of that type.
 * 2) Resistance against a nebula type, which reduces damage taken from Nebula Fields of that type only.

If both forms are explicitly mentioned for the same item, then the latter overrides the nebula portion of the former.

Calculation
Resistance is calculated in two stages:
 * 1) The overall resistance across each item that provides health is determined.
 * 2) This overall resistance is then combined with the other sources to provide the final resistance.

In this section, "health" does NOT include "ablative health".

Step 1
For simplicity, we denote any item that provides health as "armor", even though other types of equipment may also provide health.

First, we have to work out the "effective health" against each damage type for each piece of armor. The effective health is given by the formula Effective Health = Health / (1 - Resistance)

For example, Shockwave Armor III has 1,020 health and 15% Explosive resistance. Therefore, its effective health against Explosive damage is 1,020 / (1 - 15%) = 1,200.

After working out the "effective health" for each armor piece, we find the total "effective health" for each damage type. We also add the ship or module's base health (NOTE: ignore the innate resistance!) to the total. Building on to the previous example, if 1x Shockwave Armor III is put on a Revelation Cruiser (1,120 health), we get

Finally, we calculate the overall armor resistance with respect to each damage type as follows: Overall Armor Resistance = 1 - Total Health / Total Effective Health

In our example (with total health 2,140), the overall armor resistance against Explosive is 1 - 2,140/2,320 = 7.76%. For other damage types, the overall armor resistance is 1 - 2,140/2,140 = 0%.

Step 2
This part is quite straightforward. For each damage type, it is simply Overall Resistance = 1 - (1 - Resistance Effect 1) * (1 - Resistance Effect 2) * ...

For example, if a Punisher Cruiser (40% Alien resistance) has 2x Skirmish Resistor III (25% Energy/25% Explosive resistance per item) and an overall armor resistance of 35% Alien/35% Energy: Overall Alien Resistance = 1 - (1-40%) * (1-35%) = 61%

Overall Energy Resistance = 1 - (1-25%) * (1-25%) * (1-35%) = 63.44%

Overall Explosive Resistance = 1 - (1-25%) * (1-25%) = 43.75%

Misconceptions

 * Some believe that resistance stacks additive. This is incorrect: an obvious example is the fact that multiple pieces of EN Heavy Talonite Armor II (each with 50% Energy resistance) do not add up to 100% or even higher Energy resistance.
 * Some believe that the Kinetic resistance provided by (Xeno) Siege Casing applies to the whole ship. In reality, the health bonus provided by Siege Casing is considered as armor, hence its resistance only applies to this extra health.

Implications

 * Adding non-resistant armor actually decreases your overall resistance since you are increasing the total health and the total effective health by the same amount. 1-1/2 is greater than 1-2/3.
 * The multiplicative nature of resistance stacking results in diminishing returns when adding more and more resistance of the same damage type. For example, the first Kinetic Resistor III you add to a blank ship increases the Kinetic resistance from 0% to 30%, but adding a second one only further increases the resistance from 30% to 51%, not 60%. Therefore, if you are planning on building multi-purpose ships, you should try to mix resistances to maximize the average resistance across the damage types you intend to encounter.

Stasis Resistance
Stasis Resistance reduces the amount by which ship speeds are penalized due to Stasis by the specified proportion. In the case of equipped items, Stasis Resistance is applied to the parent ship.

Calculation
Stasis Resistance stacks in an additive manner, i.e. Overall Resistance = (Resistance Effect 1) + (Resistance Effect 2) + ...

If the value exceeds 100%, the ship will actually go faster when affected by Stasis.

Weapon Disruption Resistance
Weapon Disruption Resistance, often simplified as "Disruption Resistance", has two distinct effects against Weapon Disruption:
 * 1) Reduces the chance of being affected by Fire Disruption
 * 2) Reduces the amount by which charge and cooldown times are increased due to Charge and Cooldown Disruption respectively

In the case of equipped items, Weapon Disruption Resistance is applied to the parent ship or module.

Calculation
Weapon Disruption Resistance stacks in an additive manner, i.e. Overall Resistance = (Resistance Effect 1) + (Resistance Effect 2) + ..

So far, there is no way to boost Weapon Disruption Resistance past 100%.

Counter Tech
Counter Tech provide one or more of the following resistances:
 * Counter Chain, which reduce the Chain Number by an additional amount whenever a Chain weapon hits them.
 * Counter Piercing, which reduce the Piercing Number by an additional amount whenever a Piercing weapon hits them.
 * Counter Ricochet, which reduce the Ricochet Number by an additional amount whenever a Ricochet weapon hits them.

In the case of equipped items, the behavior of Counter Tech may vary:
 * Defenses such as shields, ablative armor and screens do not provide Counter Tech resistance when fully depleted.
 * Resistors always provide Counter Tech resistance.

Calculation
Resistance from Counter Tech stacks in an additive manner, i.e. Overall Resistance = (Resistance Effect 1) + (Resistance Effect 2) + ..

Trivia

 * Ex-CM LXC has confirmed that damage resistance stacks multiplicative and not additive.
 * In the Ship Factory menu, the damage resistances shown are sorted from largest to smallest.
 * The maximum value shown on the Counter Tech pop-up in combat is 10. Any value beyond that will only display as 10.