Tag Battle of Manilla

TDI Friday Read: Measuring The Effects of Combat in Cities

Between 2001 and 2004, TDI undertook a series of studies on the effects of urban combat in cities for the U.S. Army Center for Army Analysis (CAA). These studies examined a total of 304 cases of urban combat at the divisional and battalion level that occurred between 1942 and 2003, as well as 319 cases of concurrent non-urban combat for comparison.

The primary findings of Phases I-III of the study were:

  • Urban terrain had no significantly measurable influence on the outcome of battle.
  • Attacker casualties in the urban engagements were less than in the non-urban engagements and the casualty exchange ratio favored the attacker as well.
  • One of the primary effects of urban terrain is that it slowed opposed advance rates. The average advance rate in urban combat was one-half to one-third that of non-urban combat.
  • There is little evidence that combat operations in urban terrain resulted in a higher linear density of troops.
  • Armor losses in urban terrain were the same as, or lower than armor losses in non-urban terrain. In some cases it appears that armor losses were significantly lower in urban than non-urban terrain.
  • Urban terrain did not significantly influence the force ratio required to achieve success or effectively conduct combat operations.
  • Overall, it appears that urban terrain was no more stressful a combat environment during actual combat operations than was non-urban terrain.
  • Overall, the expenditure of ammunition in urban operations was not greater than that in non-urban operations. There is no evidence that the expenditure of other consumable items (rations; water; or fuel, oil, or lubricants) was significantly different in urban as opposed to non-urban combat.
  • Since it was found that advance rates in urban combat were significantly reduced, then it is obvious that these two effects (advance rates and time) were interrelated. It does appear that the primary impact of urban combat was to slow the tempo of operations.

In order to broaden and deepen understanding of the effects of urban combat, TDI proposed several follow-up studies. To date, none of these have been funded:

  1. Conduct a detailed study of the Battle of Stalingrad. Stalingrad may also represent one of the most intense examples of urban combat, so may provide some clues to the causes of the urban outliers.
  2. Conduct a detailed study of battalion/brigade-level urban combat. This would begin with an analysis of battalion-level actions from the first two phases of this study (European Theater of Operations and Eastern Front), added to the battalion-level actions completed in this third phase of the study. Additional battalion-level engagements would be added as needed.
  3. Conduct a detailed study of the outliers in an attempt to discover the causes for the atypical nature of these urban battles.
  4. Conduct a detailed study of urban warfare in an unconventional warfare setting.

Details of the Phase I-III study reports and conclusions can be found below:

Measuring The Effects Of Combat In Cities, Phase I

Measuring the Effects of Combat in Cities, Phase II – part 1

Measuring the Effects of Combat in Cities, Phase II – part 2

Measuring the Effects of Combat in Cities, Phase III – part 1

Measuring the Effects of Combat in Cities, Phase III – part 2

Measuring the Effects of Combat in Cities, Phase III – part 2.1

Measuring the Effects of Combat in Cities, Phase III – part 3

Urban Phase IV – Stalingrad

Urban Combat in War by Numbers

Measuring the Effects of Combat in Cities, Phase III – part 1

Now comes Phase III of this effort. The Phase I report was dated 11 January 2002 and covered the European Theater of Operations (ETO). The Phase II report [Part I and Part II] was dated 30 June 2003 and covered the Eastern Front (the three battles of Kharkov). Phase III was completed in 31 July 2004 and covered the Battle of Manila in the Pacific Theater, post-WWII engagements, and battalion-level engagements. It was a pretty far ranging effort.

In the case of Manila, this was the first time that we based our analysis using only one-side data (U.S. only). In this case, the Japanese tended to fight to almost the last man. We occupied the field of combat after the battle and picked up their surviving unit records. Among the Japanese, almost all died and only a few were captured by the U.S. So, we had fairly good data from the U.S. intelligence files. Regardless, the U.S. battle reports for Japanese data was the best data available. This allowed us to work with one-sided data. The engagements were based upon the daily operations of the U.S. Army’s 37th Infantry Division and the 1st Cavalry Division.

Conclusions (from pages 44-45):

The overall conclusions derived from the data analysis in Phase I were as follows, while those from this Phase III analysis are in bold italics.

  1. Urban combat did not significantly influence the Mission Accomplishment (Outcome) of the engagements. Phase III Conclusion: This conclusion was further supported.
  2. Urban combat may have influenced the casualty rate. If so, it appears that it resulted in a reduction of the attacker casualty rate and a more favorable casualty exchange ratio compared to non-urban warfare. Whether or not these differences are caused by the data selection or by the terrain differences is difficult to say, but regardless, there appears to be no basis to the claim that urban combat is significantly more intense with regards to casualties than is non-urban warfare. Phase III Conclusion: This conclusion was further supported. If urban combat influenced the casualty rate, it appears that it resulted in a reduction of the attacker casualty rate and a more favorable casualty exchange ratio compared to non-urban warfare. There still appears to be no basis to the claim that urban combat is significantly more intense with regards to casualties than is non-urban warfare.
  3. The average advance rate in urban combat should be one-half to one-third that of non-urban combat. Phase III Conclusion: There was strong evidence of a reduction in the advance rates in urban terrain in the PTO data. However, given that this was a single extreme case, then TDI still stands by its original conclusion that the average advance rate in urban combat should be about one-half to one-third that of non-urban combat/
  4. Overall, there is little evidence that the presence of urban terrain results in a higher linear density of troops, although the data does seem to trend in that direction. Phase III Conclusion: The PTO data shows the highest densities found in the data sets for all three phases of this study. However, it does not appear that the urban density in the PTO was significantly higher than the non-urban density. So it remains difficult to tell whether or not the higher density was a result of the urban terrain or was simply a consequence of the doctrine adopted to meet the requirements found in the Pacific Theater.
  5. Overall, it appears that the loss of armor in urban terrain is the same as or less than that found in non-urban terrain, and in some cases is significantly lower. Phase III Conclusion: This conclusion was further supported.
  6. Urban combat did not significantly influence the Force Ratio required to achieve success or effectively conduct combat operations. Phase III Conclusion: This conclusion was further supported.
  7. Nothing could be determined from an analysis of the data regarding the Duration of Combat (Time) in urban versus non-urban terrain. Phase III Conclusion: Nothing could be determined from an analysis of the data regarding the Duration of Combat (Time) in urban versus non-urban terrain.

So, in Phase I we compared 46 urban and conurban engagements in the ETO to 91 non-urban engagements. In Phase II, we compared 51 urban and conurban engagements in an around Kharkov to 49 non-urban Kursk engagements. On Phase III, from Manila we compared 53 urban and conurban engagements to 41 non-urban engagements mostly from Iwo Jima, Okinawa and Manila. The next blog post on urban warfare will discuss our post-WWII data.

P.S. The picture is an aerial view of the destroyed walled city of Intramuros taken on May 1945