Classification ?
Well..
Cat A : Suitable for command, awaiting command course
Cat B : Not suitable for command at this time. No set guidelines on re-assessment.
Cat C : Not sure on this one.......
Cat D : Never gonna get command, might as well move on.
There are also quasi assessments that do not result in a Category being applied. A pilot goes in and asks to be assessed and is told, " I think you should wait a year !" So you are in the penalty box with no assessment and no idea when you will be assessed ! You also do not register on the paper work as a Cat B. This means that the actual numbers of First Officers being held back from command is much higher than indicated by actual number of lilots Cat B'd.
Clear as mud !
FG