Tom from Cornwall wrote:
I guess my doubt on the original work would be the fact that when I look at 56 Division at Salerno and Mount Camino, I see a division (or bits of a division) given very difficult tasks. So not just are those engagements truly representative of 56 Division's time in Italy, but is the analysis truly representative of those engagements.
I obviously don't have Rich's in-depth knowledge of the database and models and how they evolved over time, but I had similar doubts when I looked at
Numbers, Predictions and War and tried to drill below the surface.
In theory as Rich said:
That combat is more than counting up weapons systems and laying out shooter-target SSPK matrices. That differences in doctrine, training, leadership, and motivation result in varying performance on the battlefield.
and the model should be able to provide useful analysis about the importance of say concentration at the point of attack, or artillery support; and the sensitivity of the results to key assumptions.
However, when I looked at reproducing some of the calculations I found:
- defining the battle (start, end, width, depth) is challenging eg a battalion attacking an entrenched company becomes a division vs brigade
- the opposing force strengths (and associated weapon systems) is dependent on the above, and the quality of records available
- the calculation of combat power from the number of weapon systems uses a large number of modifiers which IIRC can change the value for say tanks by a factor of 10 or more
- the model for totalling the different elements of combat power is opaque, non-linear and was derived essentially by trial and error
- estimation of results includes distance advanced and casualties which depend on the quality of data, and the judgemental mission success factor which you have commented on before
Therefore looking at the database as a whole there are a number of issues:
- non-randomness in selection of engagements to include
- potential inherent bias in the model especially in the calculation of combat power eg does it under or overvalue light machine guns; relative power of mortars vs artillery etc
- definition of forces involved eg do you count the whole division as engaged, if it was a brigade attack, as they were
potentially available?
- basic data issues eg what was the actual strength of the units on the dates, what were actual casualties
- judgements on misssion success, especially when it would have been a challenging mission
Many of these issues will be less important if they are treated consistently across the whole database, which is difficult to demonstrate without effectively replicating the whole exercise. There are some known data issues with the original NPW data eg British casualties, German casualties treated below divisional level, German Corps artillery. I'm interested in seeing Christopher Lawrence's updated book to see how he deals with these points.
