Actually, that depends upon the army you're modelling. In *most* armies, what Dan says is/was true. But from what I've read, in the old-style Soviet army low-ranking officers filled the roles usually filled by sergeants in other forces. As I understand it, only officers were usually retained for more than a single enlistment, so most non-coms had very little experience or training.

[I have no idea if this still applies in the successor forces to the Soviet army.]