High-impact practices (HIPs) are anticipated to engage both traditional and nontraditional students in different ways, providing substantial educational benefits and correlating with better retention and engagement. This study reports on the development of an analytical tool to assess the impact of individual and collective HIP participation on student retention, utilizing propensity score matching (PSM). The study findings highlight HIPs' effectiveness in supporting adult learners' retention. The results indicate that adult learners who participated in HIPs were retained at higher rates than their peers who did not engage in HIPs, underscoring the value of these practices in enhancing educational outcomes for nontraditional students.