The interest in undergraduate research as a "touchstone" for the integration of research and education has led to a large number of programs and models supported by a variety of public and private sources. Assessments have examined students' progress toward advanced degrees, clarification of career path decisions, understanding of research-associated skills or attitudes, and access to research. This study examines the benefits, outcomes, and goals for undergraduate research across disciplinary area, academic class standing, gender, ethnicity, and previous research experience. The study found consistent benefits but discipline- and ethnicity-dependent outcomes. The role of the mentor-protege relationship and the research projects' initiation both show disciplinary and ethnic group dependence. Research participation is associated with student achievement. (Contains 3 tables.)