Quote Originally Posted by Kobal2fr
Of course, using archers in box formations instead of long lines impacts their results, because their fire will be much more concentrated and focused (ie a 4 wide archer unit firing on a 15 wide spear unit will only target the 4 men in the middle), so there is still a point in having wide archer formations.
I think I've mostly debunked this, or least determined it to have little effect in game terms. First things first though, the test outcomes.

I ran 10 trials of each setup, utilizing the following conditions:

- 15 minute time limit battle on Grassy Plain, Medium Difficulty
- British Retinue Longbowmen vs. HRE Armoured Seargeants, both set to attack

The thing I varied was, of course, the configuration of the Longbows (which I controlled). In each case I configured the longbows and then allowed the Armoured Seargeants to march at them, while the lonbows fired at will into the Seargeants (i.e. I did not order them to fire, for the sake of consistency. They don't move at all, and so remain more organized and consistent). When the archers turned tail to flee, I ended the battle and counted kills. The archers seemed to get off 7 or 8 volleys each engagement.

Retinue Longbows in Standard configuration (not repositioned from default):

Trial Kills

1 18
2 24
3 28
4 20
5 19
6 25
7 29
8 32
9 24
10 30

Total 249/760
Percent 33%

Retinue Longbows in 2-Row configuration

Trial Kills

1 31
2 19
3 25
4 32
5 34
6 22
7 30
8 25
9 32
10 28

Total 278/760
Percent 37%

Retinue Longbows in 4-Column configuration

Trial Kills

1 28
2 24
3 19
4 25
5 30
6 26
7 24
8 17
9 28
10 27

Total 248/760
Percent 0.33

The results, while not completely conclusive, suggest that the spread of your archers horizontally has little if any effect. They did slightly better in 2-row configuration, but there is no difference going from the 4-column which is very narrow to standard configuration which is considerably wider. If the horizontal spread was a major factor, I would assume that each step of further spread would improve kills, yet that clearly didn't happen, so it's likely some of the difference is due simply to randomness in the game engine.

One major reason for the very similar results in all conditions is probably linked to the following: I observed from watching the volleys that the archers, no matter the configuration, appear to aim for the center of the enemy unit. I conclude this because the vast majoriy of arrows fall inside a few ranks of center, no matter the formation, where they should be much more evenly distributed if each archer picks a target to fire at in the enemy unit. This would of course reflect the realities of missle warfare at the time - everyone aims for the center of the enemy so that even if they miss, they have likely hit someone in the group. Also you can see while you hold the shift key down with your unit highlighted, that no matter where you clicked the enemy line to attack, the red pole indicating your unit's focus is in the dead center of the enemy unit you clicked. This could just be a programming convenience, but as the arrows seem to fall predominantly all around that pole, I can't just write it off as coincidence.

I will admit that the 2-row archers did a bit better on the whole. Likely this is partly luck, and possibly a little due to a factor someone earlier mentioned: that the very outside archers have a bigger cross section of the enemy unit to hit, and so a few arrows that would be short or long from a more straight on shot are now hits for them. This effect increases the closer the other unit gets, until the outside archers finally have a shot along the longest diagonal (corner to corner) of the enemy unit and thus presumably best odds of making a kill.

____XXYXXXXXX Enemy Position 1
____XXXYXXXXX
____XXXXYXXXX
____XXXXXYXXX
____XXXXXXYXX

____YXXXXXXXX Enemy Position 2
____XXYXXXXXX
____XXXXYXXXX
____XXXXXXYXX
____XXXXXXXXY

AAAAAAAAAAAAAAAC Archer Lines
AAAAAAAAAAAAAAAA

Note how Archer C's shot diagonal (indicated by Ys) gets longer as the enemy approaches, allowing a much worse shot to still hit the huge mass of enemies in front of him. He can miss quite long or short and still he will almost certainly hit an enemy body as the enemy is several extra ranks thicker from his perspective.

So to wrap up the analysis, the 2-row format appeared a slight bit better, but it may be a fluke, and certainly 4% extra kills isn't enough to warrant lots of hard work to get your archers like that. To put that in perspective, 4% is 1 in 25, so the archers only managed to kill 1 extra man in every 25, a fact that easily could just be random. So if you find it simpler to put your archers into other formations to save space, The evidence seems to suggest the impact is minimal in their performance (save for possibly having them avoid obstacles with their fire, where I agree narrowing their line to shoot into breached walls and such is the best play).