This chapter proposes the concept of life purpose as a way to evaluate service learning’s strengthening and integration of a prosocial disposition in young people over time. It deals with criteria from the feedback-loop model that universities might use to build their own evaluation tools. Service learning helps students hone skills in a community setting and think differently about their role as a protagonist in community development. Life purpose has appeared in service learning studies as a correlational outcome, covariate and mediator. To illustrate, research collaborators in a multinational study of youth purpose and service learning conducted secondary analyses on their own within-country datasets. Surveys and document analysis might provide insights to institutions regarding their service learning offerings. Students in semester-long weekly service placements could complete questionnaires each week to chart their service and purpose development, with each week’s time at the service site being one ‘trip’ through the loop.