Trevor N. Dupuy’s Combat Attrition Verities

Trevor N. Dupuy developed some hypotheses about casualty rates in combat in the process of quantifying the effects of surprise and relative combat effectiveness.[1] After testing these hypotheses against historical combat data, Col. Dupuy believed them valid enough to be considered verities. His confidence in them ranged from absolute for most to reasonable certainty for a few. The first two points are statements of combat experience, but they are directly relevant to the nature of battle attrition. As with his verities of combat, these will be discussed in more detail in subsequent posts.
Personnel Attrition Verities
- In the average battle, the attack’s numerical strength is about double the defender’s.
- In the average modern battle the attacker is more often successful than the defender.
- Casualty rates of winners are lower than those of losers.
- Small forces casualty rates are higher than those of large forces.
- More effective forces inflict casualties at a higher rate than less effective opponents.
- There is no direct relationship between force ratios and casualty rates.
- In most modern battles, the numerical losses of attacker and defender are often similar.
- Casualty rates for defenders vary inversely with strength of fortifications.
- Casualty rates of a surprising force are lower than those of a surprised force.
- In the average modern battle, attacker casualty rates are somewhat lower than defender casualty rates.
- In bad weather, casualty rates for both sides decline markedly.
- In difficult terrain, casualty rates for both sides decline markedly.
- The casualty-inflicting capability of a force declines after each successive day in combat.
- Casualty rates are lower at night than in daytime.
- Casualty rates are higher in summer than in winter.
- The faster the front line moves, the lower the casualty rates for both sides.
- Casualty rates seem to decline during river crossings.
- An “all-out” effort by one side raises loss rates for both sides.
- A force with greater overall combat power inflicts casualties at a greater rate than the opponent.
- The killed-to-wounded distribution of personnel casualties in twentieth century warfare is consistent.
- Average World War II division engagement casualty rates in Western Europe were 1% to 3% per day.
- Attrition rates in the 1973 October War were comparable to World War II.
- Casualty rates for major power forces in minor hostilities after 1945 are about half those experienced in World War II.
Material Attrition Verities
- Material loss rates are related to personnel casualty rates.
- Tank loss rates are five to seven times higher than personnel casualty rates.
- Attacker tank loss rates are generally higher than defender tank loss rates.
- Artillery material loss rates are generally about one-tenth personnel casualty rates.
- Self-propelled artillery loss rates are two-to-three times greater than for towed guns.
- The loss rates of light, to medium, to heavy artillery weapons are in the proportion: 2.2/1.8/1.0.
NOTES
[1] Trevor N. Dupuy, Attrition: Forecasting Battle Casualties and Equipment Losses in Modern War (Falls Church, VA: NOVA Publications, 1995), pp. 98-103. A slightly different version of this list was originally published in Trevor N. Dupuy, Understanding War: History and Theory of Combat (New York: Paragon House, 1987), pp. 174–180.



When historian and pundit James Jay Carafano 


