This working paper examines the sensitivity and precision of teacher value-added model (VAM) estimates obtained under model specifications that differ based on whether they include student-level background characteristics, peer-level background characteristics, and/or a double-lagged achievement score. It also tests two model variations not previously evaluated—replacing classroom average peer characteristics with teacher-year level averages, or allowing for variation in the relationship between current and lagged achievement scores based on student demographic characteristics—to determine whether they affect the VAM estimates.