Retention is crucial to the mission of an institution, and University leaders must strategize to increase student persistence. Introductory math can be a gatekeeper or a gateway. Supplemental instruction (SI) can help students' chances of success in math. This study reports on the three-term pilot of an SI program at a private mid-size institution, analyzing grades, attendance, and feedback from 806 students. Findings identified a significant difference in the GPAs of students who attended SI sessions as compared to nonparticipants. Most students found value in the sessions, such as learning how to collaborate, ask questions, and ask for help. Findings will shape the future of the SI program.