Head Start, the largest federally funded preschool program, provides comprehensive services to economically disadvantaged children and their families so that children can enter kindergarten ready to succeed in school. Performance standards include requirements for the intensity and quality of a broad range of services for children and families. This report discusses design options for potential future evaluations of Head Start quality enhancements. It describes the goals and activities associated with each of the three stages of research through the use of specific examples of potential Head Start Quality enhancements. To provide a context for the discussion of research designs in this report, Chapter II describes the Head Start program and research. Subsequent chapters are organized according to the three stages of research described here. Chapter III discusses the development phase and the information that should emerge from early efforts to establish the essential features of a quality enhancement idea and the requirements for implementing the initiative. Chapters IV through VI describe research designs for specific quality enhancement initiatives that are ready for evaluation. Chapter VII describes field testing of broad program initiatives. (Contains 27 tables and 8 figures.)