DPS (Damage Per Second)
Damage Per Second (DPS) is a measure of the rate of combat damage dealt over time by a ship, module, or drone. It is expressed in hitpoints destroyed per second. DPS does not indicate the damage types done; that is usually indicated separately. Note also that DPS is measured against a zero resistance target; actual damage done to the target will be reduced by the target's resistances to the damage type(s) dealt.
DPS is an important quantity in tanking. Ships and structures have a buffer of hitpoints which must be damaged for them to be destroyed. Doing damage at a higher rate of DPS will reduce the time required to destroy a ship or structure. Many ships or structures are able to repair or regenerate hitpoints through shield, armour or structure repair. In these situations it is necessary to do damage at a greater rate than it can be repaired if the target is to be destroyed.
Generally, DPS is averaged over a long period as ships tend not to deal consistent damage, but rather do damage in short bursts. The damage done in a single burst (usually the initial burst) is known as alpha damage or alpha-strike damage. The concept of alpha damage is important because a ship which does high alpha damage is capable of doing more damage than a comparable DPS ship over a short period, but both are capable of doing the same amount of damage over a longer time.
It is the sum of the theoretical damage done by firing all weapons consecutively averaged over one second. The theoretical DPS would be expressed as the sum of the products of the rate of fire plus flight time and theoretical damage output per cycle, all multiplied by one second:
Equation 1, for the case of N modules:
As a setup-specific value, DPS is dependent on bonuses from ship type, other fitted modules, and fitted rigs. Character skills and implants in-turn affect DPS directly and indirectly via ship, module, and rig bonuses.
Due to the varying amount of time required for different weapon modules to cycle and for payload delivery, the actual moment at which the damage is done does not occur over each second, but rather at the time of weapon contact with the target. In the case of laser weapons, this is effectively instantaneous. In the case of propelled weapons such as missiles, flight time affects actual DPS. However, due to the environment-specific nature of the 'flight_time' variable in Equation 1, it is dropped from the equation, leaving the expression typically referred to by the term 'DPS':
Therefore, the practical accuracy of the DPS value for a given ship and fitting approaches actual output as the period of time being considered increases and flight time becomes a smaller fraction of total payload delivery time.
For the specific case of identical weapon modules and an instantaneous payload delivery, the DPS calculation can be simplified to: