In this study, we analyzed the Successful/Unsuccessful Grading (SUG) program, an intervention that was founded at a large public university to support students during their transition into the first year of undergraduate engineering (EG) coursework. To understand how the SUG program impacts student retention of EG majors, we conducted an analysis guided by the following research questions: (a) Does participation in the SUG program have a positive impact on a student's likelihood of being retained within the College of Engineering? and (b) Does the SUG program have a differential impact for students who are underrepresented, female and minority students, in the College of Engineering? To address these inquiries, we leverage Bean and Eaton's (2000, 2001--2002) Psychological Model of College Student Retention as our theoretical framework and Propensity Score Analysis as our methodological tool. Findings provide insight for EG educational practices and future research trajectories regarding retention.