Col. Dupuy's rules clearly state which size factors to apply to personnel and to "tank" loss rates.

With regard to artillery, I'm assuming based on the examples given in Col. Dupuy's book, that the same personnel strength or size factor would be applied to artillery based on the size of the unit being considered. However, if an engagement was broken down into smaller units, artillery assets could be assigned from a larger unit to support a much smaller unit; it wouldn't make sense to apply the smaller unit's loss rate simply because a higher echelon artillery unit was being employed to support it? It would make sense to me to apply the size factor appropriate to level at which the artillery unit itself is assigned. In other words, Corps level artillery should only suffer a loss rate based in the Corps level personnel size regardless of what type of unit it assists (in an indirect role).

This would make sense based on the relative invulnerablility of longer ranged artillery weapons although it could be argued that the "RN" factor already accomodates this phenomenon to some extent when comparing relative effectiveness. In any event, it strikes me that artillery loss rates have more to do with breakdowns and mechanical failure than losses due to combat (hence the higher self propelled loss rate for equipment which otherwise would have many tactical advantages over towed weapons)

In terms of "other equipment", it would make sense again to apply the loss rate and size factor based on the number of personnel of the unit being considered for things such as trucks and other support vehicles. However, for direct fire equipment such towed anti tank guns, I'm not sure what strength/ size factor would be appropriate- a personnel type size factor or a "tank" type size factor?

Engagement size below division gets a little confusing. For example, if you have a battalion of infantry supported by a battery of artillery, then the battery's strength is usually counted in the unit strength if it is fully obligated to support that unit. If it is not.....then there are no clear rules.

It gets even worse if one has a battalion attacking supported by four battalions of artillery....

Needless to say, you have discovered a glitch in the model that appears when the model is used below division-level. Obviously, using a battalion-level attrition multiplier for the artillery is not really correct.

Your next point about artillery loss rates also brings up another problem created by a simplification in the weapon attrition calculation. Weapon attrition are keyed to personnel loss rates. As such, if one losses X personnel, then one losses y guns. This is based from a HERO study done long ago (see our publications list).

In all reality, artillery tends to be lost by single gun, either from mechanical, wear, counterbattery or air.....or tends to be lost in groups of 4 or 6 as batteries get overrun (usually only the defender, and only if he is penetrated). To properly model artillery attrition really needs to determine if the unit is penetrated of not, and if it is not, it uses a low attrition calculation...and if it is, then it uses a higher one to account for batteries getting overrun. This degree of complexity is not there. As such, there is a distortion created by the linear nature of the attrition calculation....when it really should be bi-polar (little or a lot).

As a final note, HERO's study setting equipment attrition based on personnel losses was used by the DOD combat modeling community (and still is?), but backwards. Their models were producing equipment loss rates but had no means to calculate casualties. Therefore they reversed HERO's tables (meaning if one losses Y guns....then you must of lost X men) and inserted it into their model(s).