A replication of an earlier study provided further support for the idea that effective principals are more accurate in their self-assessments than less effective principals. A review of the literature, of ratings made by ten nationally recognized educational experts, and of discussions with principals led to the selection of 33 important instructional leadership behaviors. A questionnaire designed to measure the use of these behaviors by principals was distributed to both the principals and their faculties in high-achieving and low-achieving elementary and secondary schools throughout California. In both elementary and secondary schools the principals' self-reports concerning their use of the leadership behaviors indicated no significant differences related to the schools' achievement levels. Compared with teachers in the high-achieving schools, the teachers in the low-achieving schools tended to agree with their principals significantly less often concerning the principal's use of the leadership behaviors. The degree of perceptual discrepancy in the low-achieving schools suggests that the self-reports of principals in those schools are not totally reliable as a means of determining the actual activities of principals in the schools. (PGD)