Large military organizations track everything! Records are kept regarding deficiencies in operation at all levels. Given the shear amount of information across a branch of the military, there needs to be a visual summary of where, who, what, why, etc to look for patterns and places to improve.
A Sankey diagram *The most well-known example of this type of diagram is Minard’s illustration of Napolean’s invasion of Russia. combined with a traditional spreadsheet format, allowed the Air Force to examine these patterns throughout the organization.