Different Courses, Different Impacts: Unequal Benefits of Learning Assistants in General Chemistry I vs II

Learning Assistants (LAs) are widely used to improve student outcomes in STEM, but their impact may vary across course levels and student populations. This multisemester, quasi-experimental study directly compared LA-supported and non-LA-supported sections of General Chemistry I and II, taught by the same instructor using identical assessments at a public R2 institution. Student performance (exam scores, DFW rates, GPA) and affective outcomes (self-efficacy, sense of belonging) were assessed using validated instruments. Results showed that LAs significantly improved exam scores, reduced DFW rates, and increased GPA in General Chemistry I while producing minimal gains in General Chemistry II, where students entered with higher preparation. Growth in self-efficacy was the strongest GPA predictor. LA programs appear most effective in early gateway STEM courses, where building self-efficacy boosts performance and persistence.