Guaporense wrote:One way to test the validity of GDP estimates might be to compare physical production with GDP figures. In China today people tend to compare rail-freight volumes or electricity consumption figures with reported GDP figures to test whether official growth figures are consistent (sometimes they are not, it's true that Chinese growth figures from the 1980's, 1990's and early 2000's tended to overestimate real growth rates, Maddison himself made substantial modifications to his estimated Chinese growth rates from 1978 to 2003, from the official levels of 9.2% to a more realistic grow rate of 7.8%).
Let's do that with coal production for Germany, which was the basic energy resource (>90% of German energy consumption was in terms of coal), hence it's strongly correlated with economic activity.
Thousand tons coal (converted into black coal equivalent for brown coal and others)
1913 -- 277,342
1914 -- 245,331
1915 -- 234,816
1916 -- 253,350
1917 -- 263,200
1938 -- 240,300
1939 -- 267,700
1940 -- 315,500
1941 -- 317,900
1942 -- 340,400
1943 -- 347,600
- From 1913 to 1917, coal output decreased by 5%, while GNP decreased by 21%.
- From 1938 to 1943, coal output increased by 45% while GNP increased by 77%.
Therefore, relative coal output was 145/95 = 152% in WW2 versus WW1. Therefore, it's true that the German economy performed better in WW2 than in WW1 (mainly thanks to the incorporation of territories plus much more imported labor in WW2 (8 million versus 1.8 million in WW1)). Also note that German coal/steel output fluctuated wildly in WW1, that was because they were learning how to manage a war economy, in WW2 they already knew how to do that so coal output didn't decrease.
But the relative GDP ratio was 177/79 = 225%, much higher than the relative coal ratio (47% higher). This suggests that GDP in WW2 was probably overestimated relative to WW1. It makes sense for coal output to be higher in wartime than in peacetime since war related industries tend to be more energy intensive so it's natural that coal output should be relatively higher than GDP in wartime and not the other way around. That is, if coal output in WW2 increased by 45%, then real GDP increased LESS than 45% and not 77%.
Similar kind of distortion appears when we look at the US coal output. US coal output (minus coal used to produce coke) was 323,202 thousand tons in 1937 and increased to 433,297 tons in 1943, an increase of 34%, while estimated GDP figures show a larger increase (around 35% to 68% depending on the estimate used). Similarly to Germany's case we have a distortion (inflation) in GDP estimation due to wartime price controls.
1) The coal production figures are questionable,the same for the conversion of black coal in brown coal:Mierzejewski;using primary German sources, gives other figures
2) The increase of 45 % is not correct :from Mierzejewski :
Hard coal in 39/40 (Protectorate included ) :214, 581,OOO. In 43/44 :278,111 : this is an increase of some 30 %
Brown coal 39/40 (without Protectorate,but the brown coal production in the protectorate was insignifiant):211,606,000. In 1943/44 (without the Protectorate )252,488,which is an increase of 20 %
3 ) MOST important, figures of production only give a total distorted picture of the situation, as coal that was not transported, was useless ,and the Reichsbahn/Inland waterways did not succeed into transporting more coal :example : the inland waterways moved in 1940/41 34,234 million ton (hard and brown coal),in 43/44 only 30,182 million ton .
For the last 5 months of 1944 there was an estimated hard coal deficit caused by shipping difficulties (RB,inland waterways) of 26,3 million ton .