Strategic bombing survey The United States Strategic Bombing Survey was a board of experts assembled to produce an impartial assessment of the effects of Anglo - American strategic bombing of Nazi Germany during the European war . After publishing its report , the Survey turned its attention to the efforts against Imperial Japan , including a separate section on the recent atomic bomb ing . In total , the reports contained 208 volumes for Europe and another 108 for the Pacific , comprising thousands of pages . The reports ' conclusions were generally favourable about the contributions of Allied strategic bombing towards victory , calling it " decisive " . Although most of the Survey ' s members were military , about one - third of the 1 , 000 - member group were civilian . The Board was not associated with any branch of the military , established directly by the US Secretary of War Henry L . Stimson and chaired by a civilian , Franklin D ' Olier . Europe . The Survey was formed on 3 November 1944 by Henry Stimson in response to a directive by President Roosevelt . The Survey was tasked with producing an impartial report on the effects of the bombing against Nazi Germany , in order to : The Report , along with some 200 supporting documents , was released on 30 September 1945 . The major conclusion of the report was that strategic bombing , particularly the destruction of the oil industry and truck manufacturing had greatly contributed to the success of the Allies in World War II . However , despite the overall contribution of the bombing , the survey concluded that the impact of strategic bombing could not be separated from the general collapse of Germany in 1945 . Successes . The Survey noted several successes against crucial industrial areas : Failures . The Survey also noted a number of failed or outcomes of limited success : On German production . The Survey concluded that one reason German production rose in so many areas was in part that the German economy did not go on a complete war footing until late 1942 and 1943 . Up until then , factories had been on a single shift in many industries and the German economy was generally inefficient and not operating at full capacity . They also noted that women ' s participation in the manufacturing field remained low , lower than during World War I . The sections of the Survey regarding the German production system remain one of the best resources on the topic . Pacific . After the European report was completed , the Survey turned its attention to the Pacific campaign . The report opens with a discussion of the Japanese strategic plans , which were based on an initial victory against the US Navy which would upset any US plans in the Pacific for an estimated 18 months to 2 years . During this time they planned to " speedily extract bauxite , oil , rubber and metals from Malaya , Burma , the Philippines and the Dutch East Indies , and ship these materials to Japan for processing " . They also noted the belief that high casualties would not be accepted by the US democracy , and that if the initial campaigns were successful , a negotiated peace was possible . Against shipping . The Survey received sufficient information to detail every ship used by the Japanese during the war . They noted that the Imperial Japanese Navy began the war with 381 warships of approximately 1 , 271 , 000 tons , and completed another 816 ships of 1 , 048 , 000 tons during the war . Of these , 1 , 744 , 000 tons were sunk ; " 625 , 000 tons were sunk by Navy and Marine aircraft , 375 , 000 tons by submarines , 183 , 000 tons by surface vessels , 55 , 000 tons by Army aircraft , and 65 , 000 tons by various agents " . The Japanese merchant fleet was likewise destroyed . They started the war with 6 , 000 , 000 tons of merchant ships over 500 tons gross weight , which was alone not sufficient to provide for the wartime economy . Another 4 , 100 , 000 tons were constructed , captured or requisitioned . However , 8 , 900 , 000 tons were sunk , the vast majority of their fleet . Of this , " 54 . 7 percent of this total was attributable to submarines , 16 . 3 percent to carrier based planes , 10 . 2 percent to Army land - based planes and 4 . 3 percent to Navy and Marine land - based planes , 9 . 3 percent to mines ( largely dropped by B - 29s ) , less than 1 percent to surface gunfire , and the balance of 4 percent to marine accidents . " Against the home islands . In total , Allied aircraft dropped 656 , 400 tons of bombs on Japanese targets , 160 , 800 tons on the home islands . This was much smaller than the 2 , 700 , 000 tons dropped over Europe , or even the 1 , 360 , 000 tons on Germany . After initial attacks from high - altitude precision bombing in which less than 10 % of the bombs fell near their targets , the Allied Air Forces switched to low - level night - time incendiary attacks against Japanese cities . On the night of 9 – 10 March 1945 , 16 square miles of downtown Tokyo were burned flat and tens of thousands were killed by the USAAF B - 29 s . ( The Survey estimated that 88 , 000 died , while the Tokyo Fire Department estimated 97 , 000 . Historian Richard Rhodes estimated more than 100 , 000 , though journalist Mark Selden considered even this figure to be too low . ) In the following 10 days , a total of 31 square miles were destroyed . The Survey notes that these attacks had little direct effect on manufacturing , with factories that were hit by bombs having less drop off in production than those that did not . However , they also noted that production dropped by 54 % during this period due to the effects of bombing : the killing , injuring and dehousing of the workers as well as the destruction of the transportation network . They noted a precipitous reduction in food availability as well , dropping from about 2 , 000 calories per day at the start of the war , to 1 , 680 for industrial workers at the height of the campaign , and less for non - essential workers . Atomic bombing . The Survey dedicates a separate section of the reports to the atomic bomb ings of Hiroshima and Nagasaki . They noted that although the blast wave was of about the same pressure as that of a high - explosive bomb , the duration of the effect was longer and that brick buildings were collapsed as far as 7 , 300 feet at Hiroshima and 8 , 500 feet at Nagasaki , while traditional wood houses were about the same , while reinforced - concrete structures suffered structural damage or collapse up to 700 feet at Hiroshima and 2 , 000 feet at Nagasaki . In Hiroshima , approximately 60 , 000 to 70 , 000 people were killed , and 50 , 000 were injured . This is out of a pre - war population of about 340 , 000 that had been reduced to 245 , 000 through evacuations . Of approximately 90 , 000 buildings in the city , 65 , 000 were rendered unusable and almost all the remainder received at least light superficial damage . In Nagasaki , approximately 40 , 000 persons were killed or missing and a like number injured . This was from a population of about 285 , 000 , which had been reduced to around 230 , 000 by August 1945 . Of the 52 , 000 residential buildings in Nagasaki 14 , 000 were totally destroyed and a further 5 , 400 badly damaged . The vast majority of Nagasaki ' s industrial output was from the Mitsubishi factories and steel plant , which was 58 and 78 percent destroyed , respectively . Unlike Hiroshima , Nagasaki featured extensive civilian bomb shelters in the form of tunnels cut into the sides of hills . " . . . all the occupants back from the entrances survived , even in those tunnels almost directly under the explosion . Those not in a direct line with the entrance were uninjured . The tunnels had a capacity of roughly 100 , 000 persons . Had the proper alarm been sounded , and these tunnel shelters been filled to capacity , the loss of life in Nagasaki would have been substantially lower . " The report also concluded that : " Based on a detailed investigation of all the facts , and supported by the testimony of the surviving Japanese leaders involved , it is the Survey ' s opinion that certainly prior to 31 December 1945 , and in all probability prior to 1 November 1945 , Japan would have surrendered even if the atomic bombs had not been dropped , even if Russia had not entered the war , and even if no invasion had been planned or contemplated . "