Institutional measures, such as the fraction of undergraduate research (UR) students who later pursue a PhD in science, do not reflect the value of UR as an educational and personal growth experience for students; moreover, little data exist to justify any causal connection between UR and career outcomes. To address these concerns, the authors conducted a five-year study of science, technology, engineering, and mathematics (STEM) undergraduates and faculty who participated in summer UR programs at four liberal arts institutions with a strong history of UR. This chapter summarizes their findings to date about the benefits to students of participating in UR.