The aims of this symposium are to examine and discuss critically the findings of a major survey of practices in instructional supervision. Data from over 1,000 teachers and their supervisors in central Pennsylvania were compiled, and findings are reported in four sections. The first section is an introduction focusing on the theoretical foundations, design, and implementation of the study to date. The second and third sections review data in order to generate a general understanding of teachers' and supervisors' experiences with and perceptions of instructional supervision. The review of teachers' data first presents respondents' general perceptions of the supervision experienced, and this is followed by an examination of a set of supervisory practices often discussed in the supervisory literature and an analysis of teachers' perceptions of the relationships between these practices and actual improvements in classroom teaching. The third section focuses on supervisors' data, presenting an initial interpretation of supervisors' reports on their practices and perceptions of instructional supervision. The final section compares and contrasts teacher and supervisor data and briefly describes future directions of the study. Appendix A provides an address to write to for information regarding the survey used in the study, and Appendix B contains a set of tables showing the data obtained from the study. (TE)