During Spring 2021, eight students at the University of the Pacific participated in an internship where they performed a DEI audit of the library's book and music score collection. An internship is one documented type of High-Impact Practices and research studies show that High-Impact Practices lead to higher retention and graduation rates. Deep learning occurred as student interns participated in developing the methodology, evaluating book and music score collections, reading assigned articles pertaining to DEI in librarianship and publishing, and providing recommendations on closing identified collection gaps. To evaluate their learning, the interns were asked to complete three surveys at the beginning, middle, and end of the project. These surveys were evaluated by a mixed methods research approach to incorporate qualitative and quantitative data in assessing the student interns' understanding of library collections, the publishing industry, and academic DEI issues. This study contributes to the literature on High-Impact Practices in academic libraries by describing a unique and valuable way to involve students in diversifying the library collection.