This paper examines leadership preparation by focusing on existing research and unaddressed questions about what happens inside and outside cohorts, a model for program delivery used in many universities. It seeks to stimulate dialogue on the impact of cohort participation on learning outcomes, professional roles, and practice. The objectives are (1) to design a nationwide research agenda about the influence of cohort delivery models on the professional practice of school leaders and (2) to develop a knowledge base of effective strategies for designing and implementing programs for school leadership. The papers primary point is that faculty in educational administration need to do more research in preparing people for positions of administrative leadership. The paper poses questions and offers suggestions about what research is necessary and which strategies might be most effective in pursuing that research. It concludes with suggestions to project designers for overcoming major stumbling blocks to a nationwide collaborative research agenda: (1) Maintain an invitational stance that encourages many to join the inquiry; (2) research design must include strategies to ensure continuing participation and financing; and (3) designers must overcome the duality of innovation and conservation common to many universities and colleges. (Contains 109 references.) (WFA)