Discussion of 1k: Holding pretest listening, reading scores, and instruction time constant, it appears that instructor qualification has a significant impact on gain, especially in the Korean context. The inference we make her is that more qualified language teachers (M.A./M.Ed. degree or CRT Certificate, versus B.A./B.S degree) can better influence the learning environment. We assume that this advantage accrues from M.A./M.Ed qualified teachers are more likely to have had exposure to TEFL methodology courses, which eventually equip them better for classroom teaching. We will return to this issue later when we conduct simulations.