The QJM (Quantified Judgment Model) and TNDM (Tactical Numerical Deterministic Model are two combat models that Trevor Dupuy developed first in 1977 as the QJM, and then heavily revised and released in 1990 at the TNDM. We do sell a computerized version of the TNDM along with manuals and training courses but at a price out of reach for most individuals. See: TNDM & QJM – The Dupuy Institute
Now, I do regularly get enquiries about the model. The combat models are described in a half-dozen books.
1. The first version of the combat model, the QJM, is fully described in Trevor Dupuy’s book Numbers, Predictions and War (1977). You may have to fish around for it, it is not in print. I see a used version for sale on Amazon.com for $77.59 and $89.95.
2. The theoretical discussions that come from his work is described in his book Understanding War (1987). This is the most significant book written by Trevor Dupuy and should be in every serious military analyst’s library. Amazon.com has a used copy for $15.89. We have new copies for $24.95: Understanding War: History and Theory of Combat – The Dupuy Institute and Ordering Information – The Dupuy Institute. An earlier theoretical book, Evolution of Weapons and Warfare (1980) is available on Amazon.com for $19.96.
3. The new model, the TNDM, was created in 1990. It is described in two books, Attrition (1990) and If War Comes (1991). Both are out of print. Attrition is for sale on Amazon.com for $123.10. I tried to warn you: We our down to our last 16 copies of Attrition – The Dupuy Institute. If War Comes is not on Amazon.com (even though it was on the Times best-sellers list). His father’s books, written in 1938 is available for $15.55 paperback and $30.00 hardcover. Trevor Dupuy’s book is available on Ebay for $45.95.
4. Some quantitative analysis of combat and a little on the TNDM is described in my book War by Numbers (2017). That book is still in print and available in Amazon.com for $37.15 (list price 39.95). It is rated at 4.7 out of 5 on Amazon.
5. Now there were a lot of reports and studies does to develop these combat models. They include:
6. There were also a dozen “International TNDM Newsletters” prepared when we were working various support contracts for the TNDM. They are here: TNDM Newsletter – The Dupuy Institute
So, we have had almost three full years of conventional war in and around Ukraine. Back in the 1970s- 1980s Trevor Dupuy assembled a list of factors (or verities) that influence and describe conventional combat. They covered combat in three different areas. They were 1) The Timeless Verities of Combat (13 verities), 2) Combat Attrition Verities (29 verities), and 3) Combat Advance Rates (15 verities).
They are listed in detail in my book War by Numbers, although I edited a few for brevity.
They are listed in detail in Trevor Dupuy’s 1987 book Understanding War. They are also listed in his 1980 book Evolution of Weapons and Warfare.
They have been around for a while. I think they are a significant list and of course have been coded into his combat models the QJM and TNDM, which actually have proven track record of making good predictions. I do think they have been underutilized and underappreciated by the wider defense community.
Anyhow, my questions for the community that reads our blog is:
1. Which of these verities have been re-confirmed by war in Ukraine?, and 2. Which of these verities have been called in doubt by the war in Ukraine?
I do want to make a shout out to Echoes of Past who keeps posting quotes by my book War by Numbers and from Trevor Dupuy’s books. His twitter account is here: Echoes of Past (@EchoesofpastX) / X
Attrition: Forecasting Battle Casualties and Equipment Losses in Modern War is no longer for sale by The Dupuy Institute. We sent out our last two copies last week. We still hold copies of everything else listed here: Books – The Dupuy Institute
There is little chance we will publish it again. The rights are held by the Dupuy family, not us. We sold 54 copies over the course of 9 years. This hardly justifies a new print run.
The Aces at Kursk book is listed on Amazon.com (U.S.) as being available as of 25 July. Do not have confirmation of that yet. It was available in the UK as of 9 July.
Just for the record, here is the definition of a “limited war” from The Dictionary of Military Terms, by Trevor N. Dupuy, Curt Johnson and Grace P. Hayes (1986). page 137.
Limited war – 1) A war looked upon by one or more of its contestants as not involving its own sovereignty or most vital interests, and as being limited in at least one respect, as, for example, to a particular geographic area, to the employment of certain resources, or to the number of contestants. 2) A war considered by a detached observer as relatively limited in some key respect, especially with regard to political objectives.
This is still the best dictionary of military terms out there. Vastly superior to what is published by the Pentagon.
Several people in their articles have referenced a 3-to-1 rule and then reference us as the source. The latest example is in a German article on Taiwan: Storming Taiwan by force of arms? | Telepolis
Of course, we are the people who are saying the 3-to-1 rule is really not correct. They obviously do not read that far.
Hadn’t done a blog post in the while. Been focused on getting a book done. Sorry.
There is a rule of thumb often quoted out there and often put in war games that a unit becomes ineffective or reaches a breakpoint at 40% casualties. The basis for this rule is a very limited body of studies and analysis.
First, I have never seen a study on when a unit become ineffective. Even though it is now an accepted discussion point, I have not seen such a study establishing this relationship and do not think that such a study exists. I am not saying that there is not a relationship between casualties and unit effectiveness, what I am saying that I have never seen a study establishing that 1) this relationship exists, and 2) what are its measurements, and 3) what is the degree of degradation.
What has been done is studies on breakpoints, and over time, a rule of thumb that at 40% a unit “breaks” appears to be widely accepted. It appears that this rule has then been transferred to measuring unit effectiveness.
The next point is the U.S. Army’s Maneuver Control manuals (FM 105-5) which in 1964 set the attacker’s breakpoint at around 20 percent casualties and the defender’s breakpoint at around 40 percent at the battalion-level. Charts in the 1964 Maneuver Control field manual showed a curve with the probability of unit break based on percentage of combat casualties. Once a defending unit reached around 40 percent casualties, the chance of breaking approached 100 percent. Once an attacking unit reached around 20 percent casualties, the chance of its halting (type I break) approached 100 percent, and the chance of its breaking (type II break) reached 40 percent. These data were for battalion-level combat.
We have never found any studies establishing the data for these Maneuver Control manuals and we do not think they exist. Something may have been assembled when they were writing these manuals, but we have not been able to find any such files. Most likely, the tables were extension of the Dorothy Clark study, even though she said that it should not apply.
Now, Dr. Richard Harrison, who spends a lot of time translating old Soviet documents, has just sent me this:
“Supposing that for the entire month not a single unit will receive reinforcements, then we will have a weakening of 30%, with 70% of the troops present. This is a significant weakening, but it does not yet deprive the unit of its combat strength; the latter’s fall begins approximately with losses of 40%.”
His source is:
N.N. Movchin, Posledovatel’nye Operatsii po Opytu Marny i Visly (Consecutive Operations on the Experience of the Marne and Vistula) (Moscow and Leningrad: Gosudarstvennoe Izdatel’stvo, 1928), page 99.
So, the U.S. came up with the 40% rule in 1954 which it disowned and then adopted in 1964 regardless. And here we have a 1928 Russian writing which is directly applying a 40% rule to unit effectiveness. I have no idea what the analytical basis is for that statement, but it does get my attention.
Units maneuver before and during a battle to achieve a more favorable position. This maneuver is often unopposed and is not the subject of this discussion. Unopposed movement before combat is often quite fast, although often not as fast as people would like to assume. Once engaged with an opposing force, the front line between them also moves, usually moving forwards if the attacker is winning and moving backwards for the defender if he is losing or choosing to withdraw. These are opposed advance rates. This section is focused on discussing opposed advance rates or “advance rates in combat.”
The operations research and combat modeling community have often taken a short-hand step of predicting advance rates in combat based upon force ratios, so that a force with a three-to-one force ratio advances faster than a force with a two-to-one force ratio. But, there is not a direct relationship between force ratios and advance rates. There is an indirect relationship between them, in that higher forces ratios increased the chances of winning, and winning the combat and the degree of victory helps increase advance rates. There is little analytical work that has been done on this subject.[1]
Opposed advance rates are very much influenced by 1) terrain, 2) weather and 3) the degree of mechanization and mobilization, in addition to 4) the degree of enemy opposition. These four factors all influence what the rates will be.
In a study The Dupuy Institute did on enemy prisoner of war capture rates, we ended up coding a series of engagements by outcome. This has proven to a useful coding for the examination of advance rates. Engagements codes as outcomes I and II (limited action and limited attack) are not of concern for this discussion. The engagement coded as attack fails (outcome III) is significant, as these are cases where the attacker is determined to have failed. As such they often do not advance at all, sometimes have a very limited advance and sometimes are even pushed back (have a negative advance). For example, in our work on the subject, of our 271 division-level engagements from Western Europe 1943-45 the average advance rate was 1.81 kilometers per day. For Eastern Europe in 1943 the average advance rate was 4.54 kilometers per day based upon 173 division-level engagements.[2] These advance rates are irrespective of what the force ratios are for an engagement.
In contrast, in those engagements where the attacker is determined to have won and is coded as attacker advances (outcome IV) the attacker advances an average of 2.00 kilometers in the 142 engagements from Western Europe 1943-45. The average force ratio of these engagements was 2.17. In the case of Eastern Europe in 1943, the average advance rate was 5.80 kilometers based upon 73 engagements. The average force ratio of these engagements was 1.62.
We also coded engagements where the defender was penetrated (outcome V). These are those cases where the attacker penetrated the main defensive line of the defending unit, forcing them to either withdraw, reposition or counterattack. This penetration is achieved by either overwhelming combat power, the end result of an extended operation that finally pushes through the defenses, or a gap in the defensive line usually as a result of a mistake. Superior mechanization or mobility for the attacker can also make a difference. In those engagements where the defender was determined to have been penetrated the attacker advanced an average of 4.12 kilometers in 34 engagements from Western Europe 1943-45. The average force ratio of these engagements was 2.31. In the case of Eastern Europe in 1943, the average advance rates was 11.28 kilometers based upon 19 engagements. The average force ratio of these engagements was 1.99.
This clearly shows the difference in advance rate based upon outcome. It is only related to force ratios to the extant the force ratios are related to producing these different outcomes.
Also of significance is terrain and weather. Needless to say, significant blocking obstacles like bodies of water, can halt an advance and various rivers and creeks often considerably slow them, even with engineering and bridging support. Rugged terrain is more difficult to advance through and easier to defend and delay then smoother terrain. Closed or wooded terrain is more difficult to advance through and easier to defend and delay then open terrain. Urban terrain tends to also slow down advance rates, being effectively “closed terrain.” If it is raining then advance rates are slower than in clear weather. Sometimes considerably slower in heavy rain. The season it is, which does influence the amount of daylight, also affects the advance rate. Units move faster in daylight than in darkness. This is all heavily influenced by the road network and the number of roads in the area of advance.
No systematic study of advance rates has been done by the operations research community. Probably the most developed discussion of the subject was the material assembled for the combat models developed by Trevor Dupuy. This included addressing the effects of terrain and weather and road network on the advance rates. A combat model is an imperfect theory of combat.
Even though this combat modeling effort is far from perfect and fundamentally based upon quantifying factors derived by professional judgment, tables derived from this modeling effort have become standard presentations in a couple of U.S. Army and USMC planning and reference manuals. This includes U.S. Army Staff Reference Guide and the Marine Corps’ MAGTF Planner’s Reference Manual.[3]
The original table, from Numbers, Predictions and War, is here:[4]
STANDARD (UNMODIFIED) ADVANCE RATES
Rates in km/day
Armored Mechzd. Infantry Horse Cavalry
Division Division Division Division or
or Force Force
Against Intense Resistance
(P/P: 1.0-1.1O)
Hasty defense/delay 4.0 4.0 4.0 3.0
Prepared defense 2.0 2.0 2.0 1.6
Fortified defense 1.0 1.0 1.0 0.6
Against Strong/Intense Resistance
(P/P: 1-11-125)
Hasty defense/delay 5.0 4.5 4.5 3.5
Prepared defense 2.25 2.25 2.25 1.5
Fortified defense 1.25 1.25 1.25 0.7
Against Strong Defense
(P/P: 1.26-1.45)
Hasty defense/delay 6.0 5.0 5.0 4.0
Prepared defense 2.5 2.5 2.5 2.0
Fortified defense 1.5 1.5 1.5 0.8
Against Moderate/Strong Resistance
(P/P: 1.46-1.75)
Hasty defense 9.0 7.5 6.5 6.0
Prepared defense 4.0 3.5 3.0 2.5
Fortified defense 2.0 2.0 1.75 0.9
Against Moderate Resistance
(P/P: 1.76-225)
Hasty defense/delay 12.0 10.0 8.0 8.0
Prepared defense 6.0 5.0 4.0 3.0
Fortified defense 3.0 2.5 2.0 1.0
Against Slight/Moderate Resistance
(P/P:2.26-3.0)
Hasty defense/delay 16.0 13.0 10.0 12.0
Prepared defense 8.0 7.0 5.0 6.0
Fortified defense 4.0 3.0 2.5 2.0
Against Slight Resistance
(P/P: 3.01-4.25)
Hasty defense/delay 20.0 16.0 12.0 15.0
Prepared defense 10.0 8.0 6.0 7.0
Fortified defense 5.0 4.0 3.0 4.0
Against Negligible/Slight Resistance
(P/P:4.26-6.00)
Hasty defense/delay 40.0 30.0 18.0 28.0
Prepared defense 20.0 16.0 10.0 14.0
Fortified defense 10.0 8.0 6.0 7.0
Against Negligible Resistance
(P/P: 6.00 plus)
Hasty defense /delay 60.0 48.0 24.0 40.0
Prepared/fortified defense 30.0 24.0 12.0 12.0
*Based on HERO studies: ORALFORE, Barrier Effectiveness, and Combat Data Subscription Service.
** For armored and mechanized infantry divisions, these rates can be sustained for 10 days only; for the next 20 days standard rates for armored and mechanized infantry forces cannot exceed half these rates.
This is a modeling construct built from historical data. These are “unmodified” rates. The modifications include: 1) General Terrain Factors (ranging from 0.4 to 1.05 for Infantry (combined arms) Force and from 0.2 to 1.0 for Cavalry or Armored Force, 2) Road Quality Factors (addressing Road Quality from 0.6 to 1.0 and Road Density from 0.6 to 1.0), 3) Obstacles Factors (ranging from 0.5 to 0.9 for both a River or steam and for Minefields), 4) Day/Night with night advance rate one-half of daytime advance rate and 5) Main Effort Factor (ranging from 1.0 to 1.2). These last five sets of tables are not shown here, but can be found in his writings.[5]
[1] The most significant works we are aware of is Trevor Dupuy’s ORALFORE study in 1972: Opposed Rates of Advance in Large Forces in Europe (ORALFORE), (TNDA, for DCSOPS, 1972); Trevor Dupuy’s 1979 book Numbers, Predictions and War; and a series of three papers by Robert Helmbold (Center for Army Analysis): “Rates of Advance in Land Combat Operations, June 1990,” “Survey of Past Work on Rates of Advance, and “A Compilation of Data on Rates of Advance.”
[2] See paper on the subject by Christopher A. Lawrence, “Advance Rates in Combat based upon Outcome,” posted on the blog Mystics & Statistic, April 2023. In the databases, there were 282 Western Europe engagements from September 1943 to January 1945. There were 256 Eastern Front engagements from February, March, July and August of 1943.
[3] See U.S. Army Staff Reference Guide, Volume I: Unclassified Resources, December 2020, ATP 5-0.2-1, pages xi and 220; and MAGTF Planner’s Reference Manual, MSTF pamphlet 5-0.3, October 2010, page 79. Both manuals include a table for division-level advances which is derived from Trevor Dupuy’s work, and both manuals contain a table for brigade-level and below advances which are calculated per hour that appear to also be derived from Trevor Dupuy’s division-level table. The U.S. Army manual gives the “brigade and below” advance rates in km/hr while the USMC manual, which appears to be the same table, gives the “brigade and below” advance rates in km/day. This appears to be a typo.
[4]Numbers, Predictions and War, pages 213-214. The sixth line of numbers, three numbers were changes from 1.85 to 1.25 as this was obviously a typo in the original.
[5] See Numbers, Predictions and War, pages 214-216.
