Best DOD numbers I can find...
Promotion to:
O2 - fully qualified nearly 100%
O3 - fully qualified nearly 100%
O4 - best qualified 80%
O5 - best qualified 70%
O6 - best qualified 50%
I know an 03 navy. Currently promotions are if you stay active duty you get promoted. 20% of 03’s get out leaving 80% for promotion etc. The break point is from 06 to 07. And yes there are a very few who meet the navy's IG who as a result are not promoted.
100% of fully qualified get promoted, pretty easy to follow, but that does not mean 100% of those up from promotion get promoted.
O-4, 80% of best qualified are promoted, but that doesn’t mean out of, say, 100 eligible for promotion, they are all rated “best qualified,” and 80 would be promoted. It says that of those rated “best qualified” (say, 50% of the total), 80% of those get promoted.
Not easy to move up, and making the O-4 cut is hard and it gets harder as they go along. Unless, of course, some promotion board takes into consideration a few other factors, like sex and race and things like that, and if you possess those “attributes,” you are viewed more favorably for promotion.
I recall back in the early 90’s, one of my Pentagon car-pool buddies in the Army told me that at the cut-off line, if the bottom ranked guy for promotion was a White guy, the board had instructions to look further down the list for the next minority and female for a second look, and that the minority or female would more than likely get the promotion bump. Not so for the White male just below the cut-off. . . no second look for him.