Journal of Moral Education
A study designed to test the effect of community service work on college ethics students found that community service work along with discussion of relevant moral issues is an effective means of moving students into the post-conventional stage of principled moral reasoning, as measured by Rest's Defining Issues Test. Other benefits of community service work are also discussed in the paper.
Boss, Judith A., "The effect of community service work on the moral development of college ethics students." (1994). Higher Education. 87.