The Pivotal Role of the Principal
Research on school effectiveness converges on a consistent finding: the principal is the second most important school-level factor in student learning, after the quality of teaching itself. Principals shape the conditions under which teachers work — the culture of the school, the coherence of its curriculum, the quality of its professional learning, the use of student data, and the expectations it holds for all students. In high-performing schools, principals are active instructional leaders who know what good teaching looks like and systematically work to improve it.
And yet the principalship, as it is currently structured in most school systems, is poorly designed to fulfill this role. Principals are expected to be instructional leaders, but they are also expected to be building managers, community liaisons, compliance officers, crisis responders, and public relations officials. The result is that instructional leadership is perpetually crowded out by administrative demands.
What Instructional Leadership Actually Requires
The research literature on instructional leadership identifies several practices that consistently distinguish high-impact principals from their peers. These include regular classroom observation with specific and actionable feedback, participation in teacher collaborative learning, coherent curriculum planning, strategic use of student performance data to guide professional development, and the cultivation of a school culture focused on continuous improvement.
Each of these practices requires substantial time, skill, and organizational support. Regular classroom observation alone — conducted with sufficient frequency and quality to be useful — requires a principal to spend a significant portion of each week in classrooms rather than in the office. This is simply incompatible with the administrative role as it is currently structured at most schools.
Redesigning the Principalship
A growing body of evidence suggests that the solution lies not in trying to make principals do more but in redesigning the principalship to make instructional leadership structurally possible. This means delegating administrative responsibilities to other staff, building distributed leadership structures in which teacher leaders take on instructional coaching roles, and providing principals with the training and ongoing support they need to develop as instructional experts.
Some of the most effective school systems in the world — including those in Singapore and Shanghai — have pursued exactly this approach, creating career pathways for teachers that lead to instructional leadership roles and designing principal positions that are explicitly focused on learning improvement rather than building management.
The Selection and Development Problem
Equally important is the question of how principals are selected and developed. In most countries, principals are selected primarily from the ranks of experienced teachers, with little systematic attention to the skills required for instructional leadership as distinct from teaching. Pre-service preparation for principals is often brief and insufficiently focused on the practical knowledge of instruction and organizational change that effective school leadership requires.
The evidence suggests that the quality of principal preparation and ongoing development matters enormously for school outcomes. Systems that invest heavily in principal development — through mentoring, peer learning networks, and sustained coaching — consistently produce stronger school leaders than systems that treat the principalship as a credential to be obtained rather than a practice to be developed.