This handbook was designed for school-level planners (school site councils, principals, parent groups, and teachers) in developing, assessing, and improving K-12 science education programs. The main body of the handbook (chapter 2) describes the most important components of an effective science education program: (1) school-level plan; (2) classroom implementation; (3) staffing and staff development; and (4) program support. In addition, the elements of exemplary science education programs are described in detail. Assessment questions and examples of activities are also offered. If the school's program lacks many or most of the elements of effective science education described here, it is suggested that improvements will clearly be needed. Chapter 3 reiterates questions from chapter 2 in the form of a convenient checklist designed to be used by school-level planners conducting on-site assessments of school programs. It is assumed that the planners will be visiting science classes, talking with teachers and students, reviewing materials, and comparing what they see with the qualities of an effective program described in the handbook. The checklist serves as a record to later analyze their observations. Various resources are presented in the concluding chapter, such as California State School Resource Centers and a list of state publications. (Author/SK)