Dupuy’s Verities: Combat Power =/= Firepower

A U.S. 11th Marines 75mm pack howitzer and crew on Guadalcanal, September or October, 1942. The lean condition of the crewmembers indicate that they haven’t been getting enough nutrition during this period. [Wikipedia]

The ninth of Trevor Dupuy’s Timeless Verities of Combat is:

Superior Combat Power Always Wins.

From Understanding War (1987):

Military history demonstrates that whenever an outnumbered force was successful, its combat power was greater than that of the loser. All other things being equal, God has always been on the side of the heaviest battalions and always will be.

In recent years two or three surveys of modern historical experience have led to the finding that relative strength is not a conclusive factor in battle outcome. As we have seen, a superficial analysis of historical combat could support this conclusion. There are a number of examples of battles won by the side with inferior numbers. In many battles, outnumbered attackers were successful.

These examples are not meaningful, however, until the comparison includes the circumstances of the battles and opposing forces. If one take into consideration surprise (when present), relative combat effectiveness of the opponents, terrain features, and the advantage of defensive posture, the result may be different. When all of the circumstances are quantified and applied to the numbers of troops and weapons, the side with the greater combat power on the battlefield is always seen to prevail.

The concept of combat power is foundational to Dupuy’s theory of combat. He did not originate it; the notion that battle encompasses something more than just “physics-based” aspects likely originated with British theorist J.F.C. Fuller during World War I and migrated into U.S. Army thinking via post-war doctrinal revision. Dupuy refined and sharpened the Army’s vague conceptualization of it in the first iterations of his Quantified Judgement Model (QJM) developed in the 1970s.

Dupuy initially defined his idea of combat power in formal terms, as an equation in the QJM:

P = (S x V x CEV)


P = Combat Power
S = Force Strength
V = Environmental and Operational Variable Factors
CEV = Combat Effectiveness Value

Essentially, combat power is the product of:

  • force strength as measured in his models through the Theoretical/Operational Lethality Index (TLI/OLI), a firepower scoring method for comparing the lethality of weapons relative to each other;
  • the intangible environmental and operational variables that affect each circumstance of combat; and
  • the intangible human behavioral (or moral) factors that determine the fighting quality of a combat force.

Dupuy’s theory of combat power and its functional realization in his models have two virtues. First, unlike most existing combat models, it incorporates the effects of those intangible factors unique to each engagement or battle that influence combat outcomes, but are not readily measured in physical terms. As Dupuy argued, combat consists of more than duels between weapons systems. A list of those factors can be found below.

Second, the analytical research in real-world combat data done by him and his colleagues allowed him to begin establishing the specific nature combat processes and their interaction that are only abstracted in other combat theories and models. Those factors and processes for which he had developed a quantification hypothesis are denoted by an asterisk below.

Share this:
Shawn Woodford
Shawn Woodford

Shawn Robert Woodford, Ph.D., is a military historian with nearly two decades of research, writing, and analytical experience on operations, strategy, and national security policy. His work has focused on special operations, unconventional and paramilitary warfare, counterinsurgency, counterterrorism, naval history, quantitative historical analysis, nineteenth and twentieth century military history, and the history of nuclear weapon development. He has a strong research interest in the relationship between politics and strategy in warfare and the epistemology of wargaming and combat modeling.

All views expressed here are his and do not reflect those of any other private or public organization or entity.

Articles: 302

One comment

  1. Greater Firepower however, translates into greater (relative) Combat Power (and perhaps greater casualty infliction potential). A unit of equal strength and experience with greater firepower will be superior to a unit which possesses less. This is very pronounced and holds especially true for armies since the 17th century.
    This leads to the question: How many Armies possessed greater firepower as well as greater Combat power, or vice versa? FP, CEV and CP differentials?
    Can overall warmaking potential be considered an intrinisic trait of Combat Power?

    There may be one flaw in the equation, in that it assumes that accumulating greater scores (TLI/OLIs) will lead to greater ouput and levels, ignoring the nature of war in a particular era and the firepower on an individual basis, e.g. if we divide the indices for the Western Front in World War 2 (1943-1944 engagements) by their force ratios, subtract the effects of Air Power, then we can observe similiar firepower levels of the belligerents, in their most natural (organized) form (platoon, battalion to Division). There will be diminishing returns. This misunderstanding might slightly overemphasize and also overestimate CEVs. Another issue is the “fitting” of values. To quantify the effects one has to often adjust the model for its accuracy, in this the general laws of war serve as the fundament to arrive at satisfactory constants, but they can obviously fluctuate at times. If we take the Winter War for instance, we see that the Soviets could not fully utilize their numerical strength, nor was the territory always suitable for employing vast amounts of armour. Thus, the combat power was degraded by environmental factors, but how great would the defensive multiplier be to not affect overall CEVs?
    Did TDI ever make an analysis of the Talvisota? I wonder how the distribution looked like.
    It has been always asserted that Soviet superiority was enormous, but if we dissect the battles we can see that this was not always true. On the contrary. Often the RKKA seemed to enjoy better odds against the Wehrmacht in the later battles, fought out in an environment that amplified their numerical strength (vast steppes). The MIA rates in the Winter War were insanely high, but the KIA rates from 41-45 were considerably greater, understandibly so. This might sound a bit confusing, but what I am trying to say is that CEVs do not have to explain the quotient of TLI/OLI when similar or greater casualty infliction occurs (or else it would simply not add up). Since historians like Prof. Mawdsley or even TDI currently assert the opposite, I find this rather confusing. Here is what I think: While there were certain learning effects, the global performance of the RKKA in 1941-45 did not substantially differ from 39 and the RKKA of 1944 was worse than that of 1941. This is the only way to explain the high bloody casualties sustained on a daily basis in relation to enemy strength. The reason: Greater Firepower translating into greater Combat power and thus also effectiveness. They are intertwined. Raising one might also raise the other and not the other way around, but they are capped (so that the exponents/power laws may never exceed a certain threshold). I do not think that the superiority of US/UK troops could always be translated (concentration and ratios aside), due to the nature of the war and the ineffectiveness of air power in the 40s. I do not think that the Soviets and Germans were comparatively armed (and a German army drawing from a similar development level as the RKKA/USSR would have resulted in comparative SEVs/CEVs), while German development levels could only partially alleviate the difficulties of the Eastern Front or e.g. American economic strength could not suddenly erase the Vietnamese jungle. In the aforementioned examples we can observe two things: Combat power could have been considerably diminished in many cases. CEVs must have been also lower in many cases for the opposing forces (than quoted by Dupuy). Dupuy overemphasized the General Staff, but it seems that IDF or Wehrmacht troops were often saved by their individual strength and that the Soviet and Allied staff might not have fared worse (at least strategically).
    It is quite possible that circumstantial factors may be the most influental of all when trying to explain the outcome of an engagement, paired by the respective armed forces strengths/characteristics (main focus). If we substitute one Army for the other in a given conflict, different outcomes might occur based on their talents. An effective Army fluent in the operational art of war and assault tactics, would have had greater success in the Finnish Winter but may have failed in the vast steppes (offensively), while a numerically superior Army with lesser development levels, might have collapsed under the strain of prolonged war.
    The IDF may shine in preemptive strikes, but might fail when (hypothetically) trying to conquer territory outside of the Gaza roam. Caesar in the bello gallico raised similar concerns when invading Gaul (with a limited number of legions). I also know of only one prolific exception, that is Alexander’s conquest of Persia.

Leave a Reply

Your email address will not be published. Required fields are marked *