A recent meta-analysis on oral assessments identifies several advantages of oral assessments, including that they: (1) develop communication skills, (2) are a more authentic assessment, (3) are more inclusive of different learning style and needs, and (4) are better at gauging understanding (Huxham, Campbell & Westood, 2012). In our math content course for pre-service elementary teachers, we think the first two advantages are self-evident. We find the third and fourth advantages compelling; however, we would like to know whether implantation of oral assessment in our class would realize these advantages. We further anticipate another advantage of oral exams over traditional exams: (5) they can be learning experiences themselves as students confront and reorganize their misconceptions in response to immediate instructor feedback. Our motivating question is: in a systematic application of both oral and traditional written assessments in our course, are the potential advantages (3), (4), and (5) empirically verified? Research questions: Q1: Does an oral assessment change our evaluation of students' achievement in the course? If so, can we qualitatively describe the differences between what oral and traditional assessments measure? Q2: How do students' perceived learning gains from an oral assessment compare to perceived learning gains from a written assessment?} We will investigate these questions using mixed methods: (A) systematically administering both oral and traditional written exams for quantitative score analysis, (B) using open coding to analyze video data of oral exams, and (C) surveying students about their perceived learning gains in each assessment format. We anticipate our results will have implications for assessment in a variety of STEM fields.