This project addressed the difficulties of teaching argument skills, a staple of liberal education, to a mixture of Communication majors and non-majors taking the course for General Education Requirement (GER) credit. The design uses independent instructor comparison of students' pre- and post-test performances, students' comparative self-evaluation of their pre- and post-test performances, as well as students' reflections on their learning in response to a separate questionnaire and independent instructor assessment of their performance in arguing those reflective claims, to analyze learning processes in an upper-level argumentation course. The results include specific content concepts and course and instructor strategies that both majors and non-majors credit for improvements in their argument skills, suggestions for assessing whether GER courses meet their learning outcome goals, and analysis of the importance of attending to students' own perceptions of and justifications for changes (or lack thereof) in their performances on tasks tied to liberal learning outcomes.