[chuckm]

A lot their "training" seem designed to weed out those who lack specific innate traits

I don't think it's entirely about innate traits. There's a lot of training that occurs before going to some these schools. For example, in the Army you're not eligible to 'try out' for Special Forces until you're an E4 grade (not sure about officers), which may take 1.5 - 3 years to achieve, assuming you enlisted as an E1. Even then a lot of guys spend 2-4 months in special training programs before going and some don't pass until their second or third attempt.

[run4yourlives]

In other words, they're controlling for knowledge and training gaps. All that remains is pure talent, really.

[falsestprophet]

O3 or O2 promotable. So, everyone trying out is very experienced.

[wumi]

unless you get an "18x" contract upon enlistment, at which point you go...

basic...AIST (infantry)...airborne...SFAS (special forces selection)

[gaius]

How does that work in Ranger battalions? I'd heard you couldn't get promoted there until you had the tab, seems like a bit of a catch 22!