This study examined the impact of undergraduate research (UR) in engineering, focusing on three particular learning outcomes: communication, teamwork, and leadership. The study included 5126 students across 31 colleges of engineering. The authors employed propensity score matching method to address the selection bias for selection into (and differential availability of) UR programs. Engineering students who engage in UR tend to report higher skill levels, but when curriculum and classroom experiences are taken into account, there is no significant effect of UR on teamwork and leadership skills. Not accounting for college experiences such as curricular, classroom, and other co-curricular experiences may overestimate the positive relationship between UR participation and professional skills. After propensity score adjustment, we found that UR provided a significant predictor of communication skills; a finding that provides support for previous research regarding the importance of communication skills as an outcome of UR. The study highlights the importance of taking into account selection bias when assessing the effect of co-curricular programs on student learning. Implications of the study include expanding undergraduate research opportunities when possible and incorporating communication and leadership skill development into required course curriculum.