Survey data from a sample of 226 school administrators and 137,601 students from districts in four Southern California counties reveal unique facets of leadership beliefs and practices. This survey study identified and analyzed the characteristics, perceptions, and practices of school administrators to determine their impact on administrator self-efficacy and teachers, school sites, students, and parents within the frameworks of instructional and transformational leadership. In addition, the survey study examined the influences of external factors such as school characteristics and student demographics on school administrators. The three major study findings are (a) school administrators generally maintain positive perceptions of their competency and effectiveness in special education as well as that of their teachers and staff; (b) several external factors, including the nature of parental interactions, the type and frequency of specific administrator duties, and the composition of the student body, are strong predictors of administrators' perceptions of self-efficacy and the incorporation of their teachers into the wider school community; and (c) administrators utilize attributes of both the instructional and transformational leadership models to fulfill the needs of their special education staff and students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]