Erdman was a member of Starfleet who held the rank of commander and served as an instructor at Starfleet Academy in the 2350s. Circa 2358, Erdman invigilated as Cadet Tasha Yar took the Priam IV test, a holodeck training simulation designed to test how Yar considered Prime Directive issues and handled decisions regarding them. In the simulation, Erdman played a corrupt Federation scientist selling primitive Priamites into Orion slavery instead of researching them. The next day, at Yar's interview with the test invigilators, Erdman passed Yar with an excellent grade. (TNG novel: Survivors)