Is it really 78% or the BUPERS 78%? Because their math is a bit funny and their percentages don't quite match reality, or seem to have anything to do with real math. Someone who had been at BUPERS explained it on the board here a while ago but it still didn't make sense.
And I don't think the Navy necessarily wants to keep the percentages the same, I think they are looking at numbers and with more people staying in the less they need.
Copied from a post I put up in the FTS thread, but it explains a little why BUPERS does what it does:
The statutory requirement is DOPMA (Defense Officer Personnel Management Act of 1980 (Public Law 96-513). Promotion opportunity is supposed to be consistent over a 5 year period. The CBO did an interesting (if a little nerdy) study on the last couple drawdowns and how the services handled them - it helps explain the process if you are really interested. This all goes back to the "up or out" argument and the effect it has on how the military does personnel business.
NPC really does calculate opportunity the "correct" way, but that number doesn't mean anything to the guy a few years out trying to figure out what his chances really are since there is no way to know if your in-zone year is going to have a board that picks up a lot of folks above zone (though it seems boards have figured out that below zone picks just fornicate the system all around). Another problem to me is that they don't provide meaningful board statistics like breaking out 1310/1320 promotion rates by community. Go back in the archives if they are still up and you can see that what community you are in really does matter (though at the O-5 level that is partly due to the way the squadron's are organized and the number of DH's in competition).
While they don't have as much flexibility with manipulating opportunity, they can mess with the YG's to get the numbers they want. The problem with all their calculations is that they always have one more unknown than they have equations, so they can suffer from the law of unintended consequences, for instance, the T-notch, which was created by a combination of the post-Cold War drawdown plus the economic boom of the late 90's. They knew that those YG's would be smaller, they just didn't know (and probably couldn't) how much smaller than requirements those groups would end up being.
Don't forget as well, that you are competing with the random selection of records you are tanked with as much as you are with the entire group. A record that would have made the crunch in one group could easily get dropped in another. Plus, it takes most boards a little bit to gel; if you are randomly dropped into the first tank then the potential spread of votes is much wider as the people on their first board start learning their way with their voting. I certainly wouldn't go so far as to call it a random process, but there is definitely variability to it.
