They only selected 27 / 300? Wow... Those are some slim odds, especially given that RIPO's do not endorse people who are not competitive.
There is no denying that it is an extremely competitive program (perhaps the most competitive of the DCO program). That is not to discourage anyone from applying, rather, to congratulate those who do get in -- it really is quite an honor.
I think the actual number submitted was 230 something; but we estimated that there were a few who actually never were put in front of the board and dq'ed before that. My guesstimation is that each RIA takes 2-3 new applicants per cycle (or they did for us). That should give you an idea of how competitive it is.
The best I can figure out here is that the board compares candidates amongst the selection pool. Which means that you are competing against the people who are applying with you. Some of us did well on tests, others didn't. One has a PhD, I just have a BA. It really depends on the total picture of your application.
I guess military references are important, but I wouldn't say they are a requirement by any stretch of the imagination. In fact, I was just interviewed by 3 officers within my RIA (all set up by my recruiter) and had no other military references (or any references really of note for that matter).
The board is pretty good at seeing who has relevant and useful experience, and is pretty good at seeing through filler. So you could have references from 2 O6s and still not get in, meanwhile a guy like me who has relevant experience is in. That's the point, can't fake experience.
Anyway that's my completely biased opinion.
-N