Me thinks Shellz doth protest too much!!
Sometimes people spout out a "statistic" like your NIH number and say, "There, gotcha." Drill down on the number and you realize it's all puffery and the number means very little, if anything, to the subject at hand and may actually be misleading.
As far as my "unfounded assumptions" about how people will interpret statistics as related to medical tests, in my case they aren't unfounded assumptions, my opinions are the result of dealing with patients and helping them interpret medical tests for the last 30 years.
Shellz, you do, or at least did, have a dog in this fight: your cadet!!! Just like me. We have both come out on the other side with our cadets where they want to be.
Fleiger83 is right on track with the crux of the problem. Kids with a history of asthma will frequently have a period during adolescence and young adulthood when the asthma goes into remission only to return as an adult. The military hopes the methacholine challenge will be predictive of those people likely to have their symptoms return as an adult or when put in environments like the Middle East. But, it's not very good at that either. But, as I've said before, it's about all they've got, though they are working on other tests.
And Mr. Mullen, I'll quit my puntificating, just for you!!!