The Principal Effect: Why Investing in School Leaders Is the Key to Solving Education’s Challenges
This post was originally published on May 26, 2026 by Forbes.
Public schools currently face a flood of crises: Chronic absenteeism, declining student mental health, teacher shortages, and learning loss are among them. Policymakers often treat each one as a separate problem to solve. But there is a single factor that is central to all of these solutions at once: the school principal.
Our new synthesis of research on the effects of principals and their preparation shows that they provide the alchemy that largely determines whether a school thrives or struggles—not just for one outcome, but for virtually all of them: staff and student attendance and morale, teacher retention, and learning gains. Certainly, fiscal resources and talented teachers matter greatly, but their orchestration into a positive school climate, strong home–school relationships, and consistent, supportive instruction depends primarily on the principal. Furthermore, principals' learning opportunities directly shape their practices and effectiveness in all of these arenas.
Investing in strong, well-supported principal leadership may be the highest-leverage strategy states and districts can use to address the many crises schools face, and yet it remains chronically overlooked.
Why Principals Are at the Center of School Improvement
American media has given us the caricature of a principal like Ed Rooney from Ferris Bueller's Day Off—consumed with managing schedules and enforcing rules, a comic figure with little impact. But research tells a very different story.
Principals shape the daily reality of every person inside a school. They influence whether teachers feel supported or depleted, whether students feel safe or invisible, and whether families feel welcomed or shut out. They can influence whether or not schools have a cohesive educational program with a strong curriculum. And their decisions about how teacher and student time are used, how feedback is given, how conflict is handled, and how resources are allocated ripple through every classroom, every day.
Researchers have identified three core areas through which effective principals drive stronger outcomes:
First, principals directly shape the quality of instruction, which drives student achievement. By observing classrooms, coaching teachers, facilitating professional learning, organizing collaboration time for teachers, and building a shared curriculum and instructional vision, effective principals enable quality teaching across the school and, consequently, improve student learning.
Second, principals are one of the strongest predictors of whether teachers stay or leave. Teachers who rate their principals as effective and supportive are significantly less likely to transfer or quit—and this effect is largest in high-need schools. In a moment when teacher shortages are straining districts everywhere, this finding deserves serious attention. Principal quality isn't just a leadership issue; it's a staffing strategy.
Third, principals set the climate of a school, which has measurable effects on attendance, behavior, graduation rates, and academic achievement. Research shows that a strong, positive school climate can actually buffer students against the negative effects of poverty on learning. The tone a principal sets, the culture they build, the trust they establish with families and staff—these are not soft outcomes. They show up in hard data.
And the impact of their training on these outcomes also shows up in hard data. After controlling for other student and teacher factors, principals who have had high-quality preparation for instructional leadership, change management, and meeting the needs of diverse learners—along with an intensive internship under the wing of an expert veteran—have significantly higher teacher retention and greater student achievement gains in English language arts. And those who have had extensive and frequent professional development in these areas show significantly larger gains in student achievement in English language arts and mathematics—with the largest gains for underrepresented student groups and for novice principals.
The Cost and Causes of Principal Turnover
Finding and training good principals is clearly important but keeping them is equally critical. There are high costs when principals leave, especially if they are replaced by an inexperienced principal from outside the school. When principals leave, teacher attrition generally increases and student test scores typically go down, in terms of both overall levels and rates of growth. The negative effects can last up to 5 years. And, in general, principal turnover is associated with decreased teacher ratings of school climate. The negative effects are sharpest in high-poverty schools—the same schools that tend to experience the highest rates of principal turnover.
The factors that cause principals to leave their schools are predictable. Turnover is more common in larger schools and those with poorer resources, and it is associated with lower salaries and working conditions that include limited decision-making authority, inadequate central office support, and punitive accountability policies that create disincentives for principals to remain in high-need schools.
How We Can Develop and Keep Expert Principals
The good news is that we know how to prepare, retain, and support principals so that they become effective and stay in the profession, which can expand our collective ability to meet education's most pressing needs. The evidence shows that principal effectiveness and retention are supported by:
Rigorous, well-designed preparation programs. How a principal is prepared is critical to their success and their longevity in the career: Principals are both more effective and more likely to stay in their jobs if they have attended high-quality preparation programs. Programs that include quality internships, applied learning, and mentorship under experienced principals—and that focus on instructional leadership, creating a positive environment, change management, and teaching diverse learners—produce significantly more effective leaders. States can have significant leverage here by supporting evidence-based licensure standards and program approval. The standards can reinforce the importance of preparing principals to create culturally responsive, equitable, and collaborative learning environments that support belonging as well as meaningful learning for both students and teachers.
Paid internships or apprenticeships. The cost of strong preparation—and the cost of taking time away from a current job to engage in clinical learning—is a genuine barrier to entry for many talented candidates, particularly those from underrepresented backgrounds. Paid internships or apprenticeships make it feasible for candidates to take the necessary time for intensive clinical placements, ideally for a full school year. Ideally, these can enable high-quality candidates to enter school leadership roles with a better-developed skill set without going into debt. States and districts that fund yearlong, mentor-supported internships are making an investment that pays returns in both leadership quality and retention.
Ongoing professional learning that fits how principals learn. Principals consistently report that the professional development formats most valuable to them are coaching and mentoring, networks where they work on shared problems with peers, and learning tightly connected to their real day-to-day challenges. Structured learning about areas of current work is appreciated but sit-and-get workshops on topics that are not connected to felt needs are viewed as a poor use of scarce time. Many principals report that both time and costs are barriers to accessing the professional learning they want and need. Policymakers who invest in free, accessible, high-quality professional learning enable principals to become more effective.
Leadership pipelines, not just individual hiring. The most effective districts don't just find good principals, they build systems that identify promising teacher-leaders early, support their development through preparation and induction, and continue investing in their growth across their careers. These pipelines don't just fill vacancies; they build a culture of leadership development that benefits the whole district.
Attention to working conditions. Principals who feel unsupported, overwhelmed, or ignored by the central office are more likely to burn out and leave. Districts that conduct regular principal working conditions surveys—as many already do for teachers—and actually use the data to inform decisions send a clear signal that principal experience matters. Responsiveness from the central office is a highly effective retention strategy.
Competitive and equitable compensation. Salary matters, and so do other forms of support, including student loan repayment assistance, housing support in high-cost areas, and adequate and equitable funding to support the neediest schools in the most challenging contexts.
Investing in Principals as a Coherent School Improvement Strategy
Perhaps the most important shift the research calls for isn't any single policy change—it's a shift in how policymakers think about the educational challenges they face. Right now, too many districts and states are addressing the challenges facing schools in a fragmented way: one initiative for absenteeism, another for mental health, and yet another for teacher recruitment. Each effort has its own funding stream, its own timeline, and its own theory of change. And principals are often left trying to implement all of them simultaneously, without adequate support.
What the evidence suggests is that investing purposefully in school leadership—from preparation through the full arc of a principal's career—is one of the highest-leverage investments a district or state can make. Principals are the connective tissue that holds everything else together. A well-prepared, well-supported principal doesn't just improve one metric; they improve the conditions that affect all metrics.
For state education leaders, this means using policy levers—licensure standards, program approval, funding mechanisms, and working conditions surveys—with a coherent vision of what excellent principal development looks like from start to finish.
For district leaders, this means treating principal supports and retention as a strategic priority, not an afterthought. It means examining whether evaluation and mentoring systems are actually helping principals grow—or just adding to their burden. It means being honest about which schools are losing their best leaders and why.
The challenges facing public schools are real, and they are serious. But the research is also clear: The path to stronger retention for teachers and better outcomes for students runs directly through the principal's office. Investing in a principal's capacity to build a positive climate and shape productive instruction will pay off many times over, offering a strong foundation for tackling the many challenges schools face today.