The same study of signal battalions took soldiers who had just taken advanced individual training courses and asked them to troubleshoot a faulty piece of communications gear. They passed if they were able to identify at least two technical problems. Smarts trumped training. Among those who had scored Category I on the aptitude test (in the 93-99 percentile), 97 percent passed. Among those who'd scored Category II (in the 65-92 percentile), 78 percent passed. Category IIIA: 60 percent passed. Category IIIB: 43 percent passed. Category IV: a mere 25 percent passed.
The pattern is clear: The higher the score on the aptitude test, the better the performance in the field. This is true for individual soldiers and for units. Moreover, the study showed that adding one high-scoring soldier to a three-man signals team boosted its chance of success by 8 percent (meaning that adding one low-scoring soldier boosts its chance of failure by a similar margin).
Smarter also turns out to be cheaper. One study examined how many Patriot missiles various Army air-defense units had to fire in order to destroy 10 targets. Units with Category I personnel had to fire 20 missiles. Those with Category II had to fire 21 missiles. Category IIIA: 22. Category IIIB: 23. Category IV: 24 missiles. In other words, to perform the same task, Category IV units chewed up 20 percent more hardware than Category I units. For this particular task, since each Patriot missile costs about $2 million, they also chewed up $8 million more of the Army's procurement budget.
Some perspective here: Each year the Army recruits 80,000 new troops—which amount to 16 percent of its 500,000 active-duty soldiers. Even if 12 percent of recruits were Category IV, not just for October but for the entire coming year, they would swell the ranks of Cat IV soldiers overall by just 1.9 percent (0.12 x 0.16 = .0192).
Then again, viewed from another angle, this would double the Army's least desirable soldiers. These are the soldiers that the Army has long shut out of its ranks; that it is now recruiting avidly, out of sheer desperation; and that—according to the military's own studies—seriously degrade the competence of every unit they end up joining. No, things haven't gone to hell in a handbasket, but they're headed in that direction. Every Army officer knows this. And that's why many of them want the United States to get out of Iraq.