Engineering service opportunities are becoming more the norm than exceptions as today's engineering curricula evolve. Research is needed to explain why so many engineering students desire service opportunities as part of their engineering education. The goal of the following work in progress is to characterize the students who are currently participating in some form of engineering learning-through-service in order to identify underlying reasons for being drawn to service. Using an array of surveying instruments, a multi-institutional assessment of student perceptions of service as a learning source, engineering epistemological beliefs, personality traits, and self-concepts - self-efficacy, motivation, outcome expectancy, and anxiety-toward engineering design is currently underway. To date what has been learned is that most service students 1) perceive service as heavily impacting their learning of professional and technical skills, 2) have slightly sophisticated engineering epistemological beliefs, 3) are typically outgoing, agreeable, and open-minded, 4) have high self-efficacy, motivation, and expectancy for success toward engineering design, and 5) have relatively low anxiety toward engineering design.