There's no such thing as "GS-16 level" anymore (not since the 70s according to Wikipedia). Beyond GS-15, management moves into the Senior Executive Service or "

There's no such thing as "GS-16 level" anymore (not since the 70s according to Wikipedia). Beyond GS-15, management moves into the Senior Executive Service or "ES scale". On the technical side, there is a Senior Technical or "ST" track. I don't know how DoD does things, but in my agency the center director is the only ES at the field center level (presumably there are lots more ES types at HQ). We have quite a few STs, basically one the top scientist in each research area is an ST.