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The importance of principals

Review identifies practices, behaviors of effective school leaders
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What makes a school principal effective?

Practices and behaviors that make some school principals more effective than others are illuminated in a new review of 20 years of research into the impact of school leaders on the academic achievement of their students.

The Edge: The impact of effective principals is stronger and broader than previously understood, according to a new review of 20 years of research. Constance A. Lindsay was one of the authors of the new study, which updates a landmark 2004 review of evidence of principal impact.

The study updates a landmark 2004 literature review that determined the leadership of a school was second only to classroom instruction as the most important school-related factor affecting student learning. The new review confirms the importance of school principals, but adds that principals’ impact on student learning may be even greater than previously thought.

Both reviews were issued by the Wallace Foundation, which commissions and publishes studies aimed at advancing leadership development among school principals and other administrators.

Constance Lindsay, Ph.D., an assistant professor at the UNC School of Education, is a co-author of the latest report, “How Principals Affect Students and Schools: A Systematic Synthesis of Two Decades of Research.” Jason Grissom of Vanderbilt University was lead author, with Anna Egalite of N.C. State University’s College of Education as an additional co-author.

The report included an extensive literature review, finding 219 high-quality studies published since 2000 that looked at the impacts of school principals. Among the studies reviewed were six that analyzed data from more than 22,000 principals in four states and two urban school districts, taking advantage of longitudinal data that did not exist for the 2004 study. The six studies also used new statistical methods that enable researchers to make causal inferences to evaluate the magnitude of principals’ effectiveness.

Among the report’s overall findings:

    • • Principals in the 75th percentile of effectiveness yield an increase in student learning in reading and math of about three months, nearly as much as the four months of increased learning generated by teachers at the 75th percentile, but across entire schools.


    • • Principals’ effects are largely indirect, stemming from their work to hire and develop teachers and in creating conditions for sound learning.


    • • Given the strength and scope of the impacts of effective principals, investments in successful strategies to recruit and retain high-performing principals are likely to have large payoffs.


    • Principals need to continue to focus efforts on educational equity.

What makes some principals effective?

The wide-ranging review examined changes since 2000 in policies impacting school leadership, changes in the makeup of the principal workforce, the evidence for the effects of principals, the attributes of principals seeming to affect student achievement, and the state of evidence on principals’ effectiveness.

The authors also identified skills and behaviors associated with effective principals, saying school leaders need to build skills and expertise in three broad categories:

Supporting instruction. Effective instructional leaders have expertise in high-quality instruction, enabling them to evaluate teachers constructively. They must be able to distinguish high- from low-quality pedagogical practices and possess skills to provide effective, structured feedback to teachers. They also need to be able to recognize the characteristics of high-impact professional development offerings.

Managing and developing people. Effective school leaders demonstrate a sense of caring for teachers that contributes to relationship development and to creating safe and nurturing environments. They must be able to communicate effectively, which contributes to building shared expectations, cohesion, and commitment to the school. Effective principals work to cultivate trust, which supports confidence in the school’s leader and sets the stage for any collaborative efforts.

Managing organizations.
Principals must have the skills needed to manage a complex organization. Effective principals must be able to manage budgets and resources, to hire and manage personnel, and to set goals and think strategically about how to meet them.

Four areas of skill focus

How do school leaders put those skills to work?

Lindsay and her co-authors identified a set of practices and behaviors of school leaders that integrate the instructional, organizational, and people skills and that were demonstrated to improve school and student outcomes. They organized the practices and behaviors into four interrelated areas:

1. Engage in instructionally focused interactions with teachers.
High-performing schools devote resources to learning opportunities for teachers who focus on instruction and building teacher capacity. Student achievement growth is higher in schools where teacher professional learning is considered an integral part of a school-wide instructional program.

A key area of a school leader’s effort is in making teacher evaluation systems successful. Effective principals secure buy-in, helping establish perceptions of legitimacy of the evaluation systems. Multiple studies demonstrated students can benefit from sophisticated teacher evaluation systems that combine structured classroom observations with high-quality feedback.

Effective principals do a good job of implementing evaluation systems, especially the teacher evaluation component. But many school leaders must learn the skills needed to give teachers meaningful feedback and authentic coaching support.

One approach shown to be effective is for school leaders to elevate coaching as a strategy for school reform, which then raises teachers’ willingness and enthusiasm to participate in coaching activities.

Research also suggests effective principals make use of data to inspire action, such as buy-ins for assessment and improvement efforts and to establish clear goals and expectations.

A suggested tactic: Use “data chats” during which administrators and teachers examine findings regarding their work, informing efforts to identify areas for improvement.

2. Build a productive climate.
A strong school climate is one that allows everyone in the school to spend their time engaging in or supporting effective teaching and learning. Evidence has shown teachers’ instructional effectiveness improves more rapidly in schools with strong professional climates. School climates featuring an academic emphasis have shown to be positively associated with students’ academic performance.

Lindsay and her co-authors identified a set of practices and behaviors of school leaders that integrate the instructional, organizational, and people skills and that were demonstrated to improve school and student outcomes.

Elements typical in strong school climates are collaboration, engagement with data, organizational learning, a culture of continuous improvement, and “academic optimism.”

Several studies indicated principals can facilitate strong school climates by helping teachers and students feel safe, valued, and emotionally supported, helping them believe their individual effort will lead to achieving academic goals.

In seeking to build and sustain strong school climates, effective principals look beyond their schools, serving as highly visible community leaders and advocates seeking to build trust between the school and the surrounding community.

3. Facilitate collaboration and professional learning communities.
Collaboration is a key element of a productive school climate, one that helps drive higher student achievement and additional positive outcomes, including lower teacher turnover.

One method for facilitating collaboration is through leading effective data use for student improvement, with principals creating opportunities for data use and training.

Elementary schools allotting grade-level teams common planning time saw higher achievement growth, particularly in reading.

Effective principals work to establish a culture of learning in which they work with teachers to create a shared sense of responsibility for student learning. One strategy is encouraging the use of professional learning communities. Evidence shows the success of professional learning communities depends on the quality of the relationship between teachers and school leaders.

4. Manage personnel and resources strategically.
Effective school leadership requires strategic management of resources, optimizing their use to support teaching and learning.

Principals need to recognize the importance of intangible resources, such as time and external social capital. Principals with better time management skills spent more of their time on instruction and in classrooms and were rated more highly by their teachers and assistant principals, according to one study. Other evidence has shown principals who spend more time interacting with parents, community members, and other stakeholders outside the school see improvement in reading measures.

Evidence also indicates managing tangible resources — primarily in the realm of personnel — predicts positive school outcomes.

More research is needed to replicate findings of the impacts of school principals and to further examine the nature of the principalship to better understand how to help school leaders be more effective, Lindsay and her co-authors said.

A key differentiator between strong and weak hiring practices that researchers have identified is principals’ access to and engagement with data about their teacher applicants. More experienced principals may be more likely to base their hiring decisions on applicants’ qualifications rather than on commonly used factors such as enthusiasm and expected fit into the school’s team.

However, constraints on principals’ time often limits their ability to engage with data when making hiring decisions. Principals are more likely to use teacher effectiveness data in school districts that have put structures in place to facilitate that engagement, when principals have the skills and expertise needed to use the data, and when they perceive the measures as being valid.

Teacher assignment and placement is another area where principals exercise personnel strategy. Principals in high-growth schools place teachers more equitably, working to match high-performing teachers to low-achieving students.

Strategic retention is another focus of effective principals, who are more likely to retain high-performing teachers — and less likely to retain their lowest-performing teachers. Principals who are successful in retaining teachers frequently focus on teacher growth, building opportunities for teachers to collaborate.

Leading for equity

The review examined a growing body of research examining the role of school principals in producing more equitable outcomes among students. Much of that research is based on qualitative data, and the authors pointed out some successful practices highlighted in the studies.

Equity-oriented school leaders consider how their interactions with teachers focused on instruction can affect equity. Those principals may work with teachers to search for alternative instruction approaches to meet the learning needs of marginalized students or engage teachers in professional development around serving the needs of subpopulations of students, such as English learners.

Principals can help educate teachers about marginalized students’ circumstances, including training about the challenges faced by students from lower socioeconomic backgrounds. Principals also play a key role in setting and communicating high instructional expectations for marginalized students. Equity-focused principals use data to target instructional resources to students who are identified as falling behind.

A key to establishing inclusive climates is how principals manage discipline with an awareness of racial disciplinary gaps. Equity-oriented principals recognize that they can pursue alternative strategies to close racial discipline gaps, including restorative justice approaches, home visits with parents to discuss discipline, and discussions with teachers about classroom management and treatment of students.

Equity-focused principals also seek to build collaborations among teachers, families, and the community, with the aim of creating purposeful connections to help schools better serve their students.

Suggestions for needed research

More research is needed to replicate findings of the impacts of school principals and to further examine the nature of the principalship to better understand how to help school leaders be more effective, Lindsay and her co-authors said.

The findings demonstrating effective school principals can drive improvements in student achievement are based on only six studies, conducted in just a few states and districts, and may not be representative, they said. Those studies also focused primarily on elementary and middle schools.

More research is needed on principals’ effects on students’ academic achievement, especially in high schools.

The authors placed an emphasis on the need for new or refined statistical approaches to isolate and measure principals’ impacts on student achievement and other outcomes. Researchers need to design quantitative studies that can rule out alternative explanations for their findings, they said.


Grissom, Jason A., Anna J. Egalite, and Constance A. Lindsay. 2021. “How Principals Affect Students and Schools: A Systematic Synthesis of Two Decades of Research.” New York: The Wallace Foundation.

Leithwood, K., Seashore Louis, K., Anderson, S., & Wahlstrom, K. (2004). How leadership influences student learning: A review of research for the Learning from Leadership project. New York: The Wallace Foundation.