Oral examination as a tool for mastery learning in undergraduate microbiology.

Undergraduate courses in general microbiology often have high content and cognitive loads, making it challenging for students to achieve content mastery of the whole curriculum. Thus, the development of manageable mastery learning interventions that work within these contexts should benefit microbiology education broadly. In this work, we describe an oral examination intervention implemented within a modified Bloom's Learning for Mastery framework that significantly improves retention of course material across low-performing students in an undergraduate general microbiology course. The intervention consumed a relatively small amount of instructor time to administer (less than 15 min per student) and resulted in no distinguishable differences in knowledge retention on the final exam between students who initially mastered the content and did not participate in the intervention and those who participated in the intervention after failing to initially master the content. Students reported overwhelmingly positive experiences with the intervention, including increased perceptions of their own content retention, increased feelings of self-pride after participating in the intervention, and a general feeling that the intervention was fair. We conclude that oral examinations are an effective mastery learning tool in the microbiology classroom and can be easily implemented by the instructor alone in small- to medium-sized courses.