This case study of a central office school improvement initiative in an urban school system examines instructional leadership practices of two junior high school principals. The school-based research focuses on correlates of school effectiveness in "low achieving" settings and the principals' capacity to "reflect-in-action," an ability to make ongoing effective decisions about unpredictable problems and situations. Study findings suggest that development and practice of instructional leadership behaviors in low-achieving schools are associated with (1) the environment (school climate); (2) the principals' own past professional experiences and staff development; (3) the issue of empowerment; and (4) the principals' capacity to reflect-in-action. The report presents a typology of principals' instructional leadership practices and an analysis of the researcher's role delineation. The study's primary implications are (1) school districts' research offices can have a positive effect on improvement initiatives through the methodologies of action research and ethnography and (2) researchers' and practitioners' capacities to achieve positive educational outcomes are enhanced by the ability to reflect-in-action. Researcher and principal can thereby become agents for change in improvement initiatives. The report concludes with two reference pages and an appendix identifying the typology and its ethnographic conceptual foundations. (CJH)