Generally, credits are negotiated, or assigned on merit. My assistant
on the show didn't negotiate for a credit, but gets one at the end, along with
Doug's. A lot of the office staff doesn't get credited on-screen, or some of
the support personnel in the art department, construction, costuming, makeup,
and other areas, because there simply isn't time; Babylon Productions, which I
co-own with Doug, employs about 225-250 people in order to make B5. So
generally the key people in each department, and their seconds, get on-screen
credit.

jms