US Naval Institute has a discussion about how the new officer evaluation report (OER) might be improved.
This was always my least favorite part of being in the service. Frequently it seemed if you were honest and followed the instructions, it was the kiss of death–damning with faint praise.
Ultimately I came to believe we would be best served if the evaluation was a simple choice of three check boxes.
___ Make this officer Commandant
___ Does OK
___ Fire the SOB
Chuck Hill's CG Blog 
Marks/OERs were too subjective and varied by command back in the day and cost some folks their career early (1990’s era RIF where I saw a few good non-rates booted for having a 2.98 average instead of a 3.00, and in each case they were due to mistakes fresh out of boot and they were no longer dirtbags). Had a commo who went to bat for us every time even if he knew he’d get thwacked, hurt his OER and he didn’t get a JG WPB command like he probably should have, still went on (and continues to be) an outstanding officer fortunately. The Air Guard/Air Force is pretty all over the place with their version of marks (EPR) too, I think you have to hand-build a F-35 in order to get ‘exceeds’ in an area 🙂