This paper presents findings of a study that examined how principals' instructional management behaviors are conditioned by contextual factors such as principals' personal characteristics, school district conditions, and other external factors. The study used the instructional leadership model advocated by S. T. Bassart, D. C. Dwyer, R. Rowan and G. V. Lee (1982) to analyze the national database available from the Schools and Staffing Surveys (SASS) established by the National Center for Education Statistics (NCES). Findings suggest that a number of contextual factors significantly influenced principals' effectiveness in instructional management. Overall, factors such as gender, age, education, work experience, school size, urbanicity, and percentage of minority enrollment were tested as significantly related to principals' perceived effectiveness in instructional leadership, either positively or negatively. Some factors that were previously assumed to be important factors were found to be insignificant. For example, principals' training, their academic major in education administration, their school's cultural diversity, and affluence level of students' families did not seem to affect principals' instructional management behaviors. Thirteen tables and one figure are included. (Contains 38 references.) (LMI)