Research in constitutional and administrative law occupies a distinctive place in legal scholarship because it deals with the structure of government, the control of public power, institutional accountability, and the protection of rights. A sound research design is essential in this field because legal inquiry must remain systematic, coherent, and methodologically defensible from the framing of the problem to the drawing of conclusions. This paper explains the meaning, components, and practical application of research design in constitutional and administrative law studies, with particular attention to doctrinal, comparative, historical, and empirical approaches. It also identifies common methodological problems, including overbreadth, selective use of authorities, weak case selection, and the difficulty of linking legal doctrine with institutional practice.