It seems correctly caveated; it is really hard to measure intelligence. People could have different skill sets and talents, some of which test better or work better in an academic setting. It isn’t obvious how much teaching experience could tell out about some hypothetical intelligence-horsepower or something like that.
It is surprisingly easy (and cheap), actually. That's why the military does it all over the world. People who score too low are a liability for the military (and not only are they less useful, they tend to be more dangerous than enemy). People who score well are shepherded towards signaling, engineering, that sort of thing. Average people get to be "normal" soldiers.
That “the military” (which one? Or is it Earth Defense Force?) claims to test something doesn’t mean they actually accurately test it. If they actually claim that. I suspect they are more interested in testing aptitude and skills for particular types of tasks.
