This course is a key component of the PhD program in Public and International Affairs, providing students with a solid grounding in the principles of research design and the ethical foundations of social inquiry. Rather than focusing narrowly on the technical details of particular methods, the course addresses the broader choices, dilemmas, and problems that all social science research must confront, regardless of methodological approach. These include how to formulate meaningful and original research questions, how to conceptualize and operationalize key concepts, how to think critically about measurement, and how to design strategies that connect theory to evidence in a coherent and rigorous way. Throughout the course, students will engage with issues that cut across methodological traditions, such as the role of inference, the trade-offs involved in different research strategies, and the ethical responsibilities of researchers. A variety of approaches will be used as illustrations -including surveys, experiments, case studies, interviews, and the use of secondary data - but the emphasis will remain on the underlying design challenges common to them all. By grappling with these questions, students will develop the ability to design research that is both methodologically sound and substantively significant, equipping them with the critical skills needed to advance their dissertations and contribute to broader scholarly debates.