Learning outcomes assessment has been widely used by higher education institutions both nationally and internationally. One of its popular uses is to document learning gains of students. Prior studies have recognized the potential imbalance between freshmen and seniors in terms of their background characteristics and their prior academic performance and have used linear regression adjustments for these differences, which some researchers have argued are not fully adequate. We explored an alternative adjustment via propensity score weighting to balance the samples on background variables including SAT score, gender, and ethnicity. Results involving a cross-sectional sample of freshmen and seniors from seven groups of majors within a large research university showed that students in most of the majors demonstrated significant learning gain. Additionally, there was a slight difference in learning gain rankings across major groupings when compared to multiple regression results.