Attrition Divider

[sPzAbt653]

The Attrition Divider :

From the manual, 8.5.2
It is possible to set the Attrition Divider value for a Scenario by using the Edit > Set Attrition Divider item in the Force and Deployment Editor menus. This value directly affects the lethality of most combat. Within the combat code, the effective losses for any item of equipment are divided by this number before being applied to the unit. The default value is 10. Minimum is 1 and maximum is 100.

That's all it says, so lets try to explain a little more. Lets use as an example an assault on a defended position in a one day per turn scenario with the default Attrition Divider (AD) setting of 10. Assume that on turn 1/day 1 the attack results in 20% attacker casualties and 50% defender casualties. The defender does not retreat. On turn 2/day 2 the combat is repeated, resulting again in 20% attacker casualties and 50% defender casualties, with an overall result of the defender evaporating and the attacker successfully advancing into the position.

Now lets change the scale to one week per turn, and leave the AD setting at 10. Using the same combat examples and results as above, it now takes two weeks to clear the defended position instead of two days. If you wish to capture the defended position in the same two day time period as in the first example, you would need to change the AD to a setting of 5, which results in 2x the Default Losses.

Now switch the scale to six hours per turn, and with the default AD setting of 10, and the same combat examples as above, you would gain the defended position in twelve hours. In order to get the same two day result as in the first example, an AD setting of 35 is needed, which results in 0.25x the Default Losses.

Setting Losses
1 10x
2 5x
5 2x
10 1x (default)
20 0.5x
35 0.25
50 0.2x
100 0.1x

At the maximum setting of 100, combats would result in 0.1% of the losses incurred by the Default Setting of 10. At the minimum setting of 1, combats would result in 10X the losses incurred by the Default Setting of 10. Any setting from 1 to 100 can be used.

Its obvious that the setting of this value is very important to any scenario. What's not obvious is what the setting should be for each scenario. Playtesting for realistic results is the best method of determining the appropriate AD setting for each scenario, but Bob Cross has contributed this general guideline for turn length and setting :

Whole-week: 2
Half-week: 4
Full-day: 14
Half-day: 28
6-hour: 56

Many scenarios use the default setting of 10. If you are playing a scenario and feel the combat results aren't appropriate, you can open the scenario in the editor and check the AD setting. If it is set at 10, you may want to adjust it to see what effect it has.

[sPzAbt653]

Except for the initial quote from the manual, those are only my thoughts on the subject. If anyone has a different view, or any additions to make, please do so because I'm just trying to reach a reasonably accurate description of the AD as I believe it is a critical setting.

[Oberst_Klink]

Glad to know you're still there Steve.

I perhaps we should make Bob's AD values part of the sticky thread, too. They helped me enormously 'updating' some pre-v3.4 scenarios that otherwise suffer from the 'ignore losses' tactics and syndrome for defending players at PBEM matches.

As to guidelines, assuming the values are linear, then here would be the values for the setting, along with some values I've actually used for it:

Whole-week: 2 (Examples: Germany 1945 & Soviet Union 1941)
Half-week: 4 (Examples: CFNA, France 1944, The Next War 1979)
Full-day: 14 (Examples: Killer Angels 1863, Cambrai 1917, Kaiserschlacht 1918; Exception: Okinawa 1945)
Half-day: 28
6-hour: 56 (Example: Waterloo 1815, actually set to 40)

Okinawa is the exception to the rule due to the need to model the Jap cave defenses. It uses an AD of 50. And, at 40, Waterloo must have needed to be bloodier than normal WWII.

Erik Nygaard was so kind to email me some reference values from his scenarios, too:

Tarawa (experimental): 500m/6 hour: MRPB = 2, Attr = 30
Crete: 1km/6 hour: MRPB = 5, Attr = 5
Malta: 1km/6 hour: MRPB = 5, Attr = 10
Market Garden: 1km/6 hour: MRPB = 4, Attr = 12
Varsity: 1km/6 hour: MRPB = 5, Attr = 35
Torch: 5km/6 hour: MRPB = 4, Attr = 10
Race for Tunis: 5km/half day: MRPB = 5, Attr = 8
Weserübung: 5km/half day: MRPB = 3, Attr = 15
Russia-Japan 1905: 10km/full week: MRPB = 7, Attr = 30

Klink, Oberst

[sPzAbt653]

... perhaps we should make Bob's AD values part of the sticky thread ...

They were in the first post ! I miss Nothing !! (says Schultz !)

The MRPB could probably use some explanation also, but I think that is something that is easier to comprehend than it is to explain, so I'll leave it alone for now. And it seems that in most cases a setting of 3-5 is sufficient ... much better than 99.

[shunwick]

ORIGINAL: sPzAbt653

Playtesting for realistic results is the best method of determining the appropriate AD setting for each scenario..

Steve,

Playtesting is the only method for determining the correct setting. Bob's quidelines are ok but if you look at Eric's examples for his 6 hour scenarios you can see that they vary widely.

If you know what combat losses you should be seeing then that will help by putting you in the general vacinity and from there playtesting lets you fine tune it.

Best wishes,
Steve (no, the other one...)

[sPzAbt653]

Right on Steve, and in addition to knowing historical combat losses, matching historical combat results is tied into the AD. If you have a scenario that was an historical trench style slugfest but in playtesting the units are retreating and/or evaporating all over, take a look at the AD. One the other extreme, an historically fluid battle can become a static front line if the AD setting is improper.