I've never really dug into the stat. When I was working Army side, I knew that the manuals were written at a 5th grade reading level, as it was expected that a new soldier would have that ability. Side note, leadership courses in the Army have language\communication requirements. The military (legally) can't contract with the bottom 1\6th of ASVAAB test results, which means that 5th grade reading level expectations excludes that group...