On the surface, the combat system in GC2:DA is much more complicated, but in a way, it is easier to analyse. If you haven't, please check the sticky post describing the combat system in the beta forum.

I don't know if something like this has been posted before, but I'm going to post a formula for the 'theoretical' combat effectiveness of a fleet in DA and then describe how I arrived at it, the assumptions that go into it and where it breaks down.

Theoretical Fleet Power = Attack*(Defence + Hitpoints)

Attack and Defence are the total fleet values and we assume the enemy has only one type of weapon and the fleet uses the appropriate defence.

There is an implied multiplier of 1.0 on defence. For fleets of smaller ships or ships which have very low defence the multiplier can be as low as one half. A little bit of defence is not as helpful.

The formula is less predictive in fights where there are fewer ships because it becomes important whether each individual ship survives a round. I suspect that defence is usually more important in smaller engagements, but it depends on the particulars.

Also, attack becomes less useful as your total attack approaches twice the enemy's (Defence + Hitpoints), because the fastest you can kill the enemy is in one round (and they can still shoot back and kill you).

There are a couple of steps to arrive at the formula:

1. In one round, each point of attack generates half a point of damage, on average.

2a. When the damage of an individual weapon is much larger than one ship's total defence (unlikely), in one round each point of defence stops half a point of damage, on average.

2b. When the damage of an individual weapon is small compared to one ship's total defence (more likely), each point of defence stops one full point of damage, on average. This is because defence will rarely roll under the individual weapon damage, until it is close to depleted (ie has stopped it's rating in rolled weapon damage).

3. Each hitpoint takes one point of damage

4. Here the biggest theory part. In most fleet battles there is a granularity so that it matters whether an individual ship lives or dies or dies in a particular round. If you have a very large fleet battle, the granularity is less. If we imagine a battle between 100 Drengin Mk23 frigates and 100 Altarian Mk27 frigates we can measure progress by what fraction of each fleet is destroyed in the first round. In a large battle and assuming homogenous fleets, whichever side loses the greatest fraction of its fleet in the first round is going to lose the battle.

On average, the fraction of your fleet that gets destroyed in the first round is:

Friendly Loss Fraction = 0.(Total Enemy Attack)/(Total Defence + Total Hitpoints)

The fraction of the enemy fleet you can expect to destroy in the first round is:

Enemy Loss Fraction = 0.(Total Attack)/(Enemy Defence + Enemy Hitpoints)

Note that in a real fight, the fraction of the fleet destroyed is somewhat less than this, because ships that are damaged or have depleted defences can come back with full defences next round.

If you are going to win, then your loss fraction has to be less than his loss fraction.

0.5*EA/(D + HP) < 0.5*A/(ED + EHP)
EA*(ED + EHP) < A*(D + HP)
Enemy Fleet Power < Friendly Fleet Power
Fleet Power = A*(D + HP)


So, the summary:

- A*(D + HP) is a pretty good 'theory' measure of a fleet's power
- The total defence strength 'D' can be as little as half as effective if you have very low defence per ship
- Defence can be more effective in fights involving fewer ships. For instance, if one of your ships has around half as much defence as the entire opposing fleet's offence you probably cannot be defeated.
- Additional attack is less useful as A approaches twice your opponent's total (D + HP). You can only kill them once.