Publicly engaged universities, faculties, and students rarely have the luxury of fitting public problems to research methods. On the contrary, community-engaged and public-service researchers must be flexible and nimble with their methodological tools, able to systematically and rigorously analyze pressing questions in cooperation with community partners and in response to public problems. Whether the questions at hand involve the program factors in international service learning (ISL) that are most likely to invoke deep learning and reflection on the part of students, or how a community organization can demonstrate its effectiveness and articulate the work it does, the research problem, purpose, and questions must drive selection of methods. We begin with these three related assumptions: (a) choices and decisions about research design and methods should be informed by the purpose of the research; (b) quantitative, qualitative, and mixed method research approaches can generate important knowledge about programs, phenomena, problems, people, and policy but will always have specific limitations; and (c) given such limitations, criteria for assessing the quality of a particular research approach should be well understood and explicit throughout the research process.