PASL is also referred to as School or Instructional Leadership. Instructional leadership is generally defined as the management of curriculum and instruction by a school principal. This term appeared as a result of research associated with the effective school movement of the 1980's, which revealed that the key to running successful schools lies in the principals' role. However, the concept of instructional leadership is recently stretched out to include more distributed models which emphasize distributed and shared empowerment among school staff, for example distributed leadership, shared leadership, and transformational leadership.
The concept of instructional leadership emerged and developed in the United States within the effective school movement of the 1980s. The research resulting from this movement revealed that a principal is critical to success in children-s learning within poor urban elementary schools. This research revealed that the personality characteristics of the ideal principal are strong mindedness, directness, top-down management and charisma.
During the 1990-s, a strong instructional leadership model was still at the center of the educational leadership discussion, because of its effectiveness in the schools. However, since then this concept has been criticized for focusing too much on the individual principal-s heroic role. As a result, the scholars started to explore leadership models to supplement these critics and point out the distributed nature of instructional leadership, such as transformational leadership, teacher leadership, shared leadership, and distributed leadership, all of which understand educational leadership as broader perspectives practice that includes school communities. Moreover, the accountability movement of the 21st century sheds new light on instructional leadership, since this paradigm puts more emphasis on the learning outcomes for students.
Researchers have further defined instructional leadership to include different approaches. First, the concept of instructional leadership could be divided into an "exclusive" and an -inclusive- approach. Researchers who count instructional leadership as "exclusive" regard the principal as the sole holder of responsibility when it comes to setting goals for the school, supervision, and in developing instruction that enhances academic achievement. This perspective tends to focus only on the role of principals as instructional leaders (e.g. Hallinger & Murphy, 1985).
However, other researchers have recently expanded the concept of instructional leadership to include not only principals, but also other school staff. They take an "inclusive" approach to instructional leadership. Especially, Marks and Printy (2003) have pointed out the importance of the collaboration between principals and teachers to develop curriculum and instruction for improving pupils' performance. Thus, they conceptualized this inclusive approach as -shared instructional leadership- and understood the role of principals as that of -leaders of instructional leaders-. Hallinger (2003) has argued the transformational leadership approach, in which leadership is shared with school staff; this approach is said to empower staff. Transformational leadership is a good supplement to the instructional leadership approach that focuses solely on principals and top-down strategies. For this reason, Hallinger has proposed the integration of instructional and transformational leadership approaches.
Second, researchers have classified modes of instructional leadership according to "direct" and "indirect" activities. The former is considered a "narrow" mode and the latter a"broad" mode of instructional leadership. This distinction is due to the fact that a direct perspective focuses only on immediate actions related to instruction, such as classroom observation and curriculum development, whereas an indirect perspective broadly focuses on indirect activities, such as creating the school climate, as well as direct activities.
Several researchers have outlined the characteristics and components of instructional leadership. Hallinger and Murphy's (1985) conceptual model has been most widely used in empirical studies of instructional leadership. The authors proposed the key role of instructional leaders in three dimensions: 1) Defining the school mission, 2) Managing the instructional program, and 3) Promoting a positive school-learning climate. In these three dimensions, principals have different functions. First, their analyses of a leader-s role in defining the school mission focuses on two functions: framing clear school goals and communicating clear school goals. Second, in the area of managing the instructional program, principals have three functions: supervising and evaluating instruction, coordinating curriculum, and monitoring student progress. Third, in regards topromoting a positive school-learning climate principals have five functions: protecting instructional time, promoting professional development, maintaining high visibility, providing incentives for teachers, and providing incentives for learning.
Murphy (1988) proposed four major dimensions of instructional leadership: 1) Developing mission and goals, 2) Managing the education production function, 3) Promoting an academic learning climate, and 4) Developing a supportive work environment.
Duke(1982) suggested six functions of instructional leadership related to teacher and school effectiveness: 1) Staff development: recruitment, in-service education, and staff motivation, 2) Instructional support: organized activities to maintain an environment geared towards improving teaching and learning, 3) Resource acquisition and allocation: adequate learning materials, appropriate facilities, and skilled support personnel 4) Quality control: evaluation, supervision, rewards, and sanctions, 5) Coordination: activities that prevent cross-purposes or duplicate operations, and 6) Troubleshooting: anticipation and resolution of problems in school operation. The first four functions of instructional leadership are directly related to instruction behaviors, whereas the remaining functions are indirectly relevant to instructional activities.