PlanetsCentral

EPRecrewScaling = 30

When crew members are killed in combat, the average experience of the remaining crew doesn't change.

When new crew members are added to a ship, the experience of the new and old crewmen is mixed proportionally.

Crew_experience =
      ((Old_crew * Old_experience) + (New_crew * New_experience))
       / (Old_crew + New_crew)

In particular, when you capture a ship by killing off its crew, it will start out with the experience level of the capturing ship (Old_crew will be zero in that case).

Since experience isn't only a matter of brains, but also a matter of technology - fine-tuned engines, weapons, computer archives -, you also keep parts of the experience which is in the ship's technology:

Tech_experience = Old_experience

These two components form the new experience:

New_experience =
       (Tech_experience * EPRecrewScaling
        + Crew_experience * (100 - EPRecrewScaling))
       / 100

That is, at the default configuration, technology affects experience to 30%, and crew affects it to 70%.

Example: assume you capture a ship, and give it 10 of your crewmen. Your ship has 3000 EP, the captured one had 1000. Since the old crew got completely killed, the new Crew_experience is exactly 3000 (=(0*1000 + 10*3000) / 10); the Tech_experience is 1000 (same as the old ship's experience). This yields a new experience of 2400 (=30%*1000 + 70%*3000) for the captured ship. The captor's experience will not change.

Assume now you add 50 more crewmen at a starbase. Crewmen from starbases start with 0 EP. The new Crew_experience now is 400 (=(10*2400 + 50*0) / 60), the Tech_experience is 2400, so the new ship experience is 1000. The base's experience will not change.

Here is a list of all actions which add crew to a ship:

• Fix ship or Super Refit at a starbase: these will add crew members which have no experience. Likewise, newly-built ships have no experience no matter what the experience level of the starbase is.
• Capturing a ship in combat: this adds crewmen from the capturing ship, which have the experience of that capturer. Note that all the original crew has been killed, and thus doesn't contribute Crew_experience here.
• Boarding a ship: this adds crewmen from the boarding ship. Depending on the boarded ship's race, part of its crew will run traitor which affects the computation: a boarded Privateer ship will remain unchanged, because all the crew runs traitor.
• The Exchange Crew mission of Academy ships: this adds crewmen from the Academy ship, usually with higher experience. Likewise, the Academy ship receives crew from the ship it is re-supplying.

► Note: Note that, unlike all other experience changes, these changes apply immediately. While experience gain from movement, training, etc. will not have effect until at the end of the turn, changes through crew interchange will immediately take effect. These changes also exempt the rule that a ship can only advance one level per turn. If a Level-4 battlestar captures a small freighter, that freighter will most likely start with Level-3 crew.