THE CONCEPTUALIZATION, MEASUREMENT, AND EFFECTS OF SCHOOL LEADERSHIP Introduction to the Special Issue

This article highlights growing evidence that leadership matters to academic success in schools and examines several needs for additional research to improve our understanding of this relationship. The measurement, conceptualization, and effects of school leadership are discussed as important topics around which the field needs additional knowledge to understand the ways in which school leadership can make a difference to the quality of teaching and learning. This article reviews several promising studies that present new knowledge about (a) a reciprocal effects model of collaborative leadership, (b) advances in the conceptualization and measurement of distributed leadership in schools, (c) the assessment of learning-centered leadership, (d) the measurement of school leadership behaviors using annual surveys and daily instructional logs, and (e) the relationship between principal leadership and norms for effective instruction in schools. As a group, these studies provide new means of conceptualizing, measuring, and understanding the effects of leadership in schools.