Drawing on 20 years of research and 219 studies, the synthesis also identifies four behaviors of principals linked to positive school outcomes, suggests continued reorientation of the work of principals toward educational equity, and offers an emerging vision of how the four behaviors can be carried out with an equity focus.
How Principals Affect Students and Schools: A Systematic Synthesis of Two Decades of Research, commissioned by The Wallace Foundation, updates a groundbreaking 2004 review of the literature on school leadership by Kenneth Leithwood, et al., that has been downloaded more than 800,000 times from the foundation’s website. The authors of the new report are Jason A. Grissom, the Patricia and Rodes Hart professor at Vanderbilt University; Anna J. Egalite, an associate professor at North Carolina State University; and Constance A. Lindsay, an assistant professor at the University of North Carolina at Chapel Hill.
“The results of this new study are striking, suggesting that the link between leadership and learning is even stronger than we had previously known,” said Will Miller, president of The Wallace Foundation. “Of course, an effective principal’s ability to create better outcomes for students happens primarily through working with teachers, so rather than thinking in terms of either/or, the evidence suggests we need a balance of investments in developing great principals and great teachers. In that spirit, we hope this report will be helpful to practitioners, policymakers, and others who are working to improve equitable outcomes for more young people.”
The research synthesis addressed three questions:
- How much do principals contribute to student achievement and other school outcomes?
- How do principals matter? What are effective leaders’ skills, behaviors and characteristics?
- Who are public school principals in the United States, and how have their characteristics changed over the past two decades?
To gauge the impact of principals on student learning, the researchers examined six rigorous studies that followed the same schools and principals over multiple years by using district and state longitudinal data available only in the last decade or so. The studies permit plausibly causal inferences about principal impacts; in analyzing the six together, the authors were able to make more precise estimates than previously possible of the impact of effective principals.
The six studies estimating principals’ effects showed that their contributions to student achievement were nearly as large as the average effects of teachers identified in similar studies – but larger in scope because effects are averaged over an entire school rather than a classroom. Replacing a below-average elementary school principal (at the 25th percentile of effectiveness) with an above-average principal (at the 75th percentile) would result in an additional 2.9 months of math learning and 2.7 months of reading learning each year – larger than the effects seen from more than two-thirds of educational interventions examined in a recent review. (For comparison, moving from a teacher at the 25th percentile of effectiveness to one at the 75th percentile of effectiveness would yield an additional 3.7 months of math learning and 3.8 months of reading learning.) The researchers emphasized that principal and teacher effects on student learning cannot be separated, as part of the impact of an effective principal is to make it more likely a student will have an effective teacher.
In addition, effective principals yield benefits for student attendance, reduction in exclusionary discipline, and teacher satisfaction and retention, particularly for high-performing teachers.
“Our findings on the importance of principals’ effects suggest the need for renewed attention to strategies for cultivating, selecting, preparing, and supporting a high-quality principal workforce. The payoffs to successful strategies appear very large for student learning and for other important outcomes, such as student attendance and teacher turnover,” said Grissom. “Given not just the magnitude but the scope of principal effects, which are felt across a potentially large student body and faculty in a school, it is difficult to envision an investment with a higher ceiling on its potential return than a successful effort to improve principal leadership.”
For insights into the practices of effective principals, the research team drew on research studies undertaken since 2000, the latter end of the time period covered in Leithwood, et al.’s How Leadership Influences Student Learning. The 219 studies the authors ultimately examined in depth were culled from more than 4,800 they had identified in a systematic review of the literature. Based on the weight of evidence, the researchers identified four key behaviors of effective principals:
- Focusing on high-leverage engagement around instruction, which includes teacher evaluation, feedback and coaching, and establishing a data-driven instructional program • Establishing a productive school climate, in which all individuals in the school can spend their time engaging in or supporting effective instruction
- Facilitating collaboration and professional learning communities
- Using personnel and resource management processes strategically, including intangible resources like time and social capital; strategic teacher hiring is key
To carry out those behaviors, the study says, principals need three types of skills: people skills, instructional skills, and organizational skills.
“The education field has tended in recent years to focus on developing principals’ instructional skills as the key to increasing student learning, but this synthesis suggests that effective principals actually use a much broader toolbox,” said Egalite.
The report also describes the composition of the current principal workforce and how it has changed from the recent past. Over the past two decades, the researchers found, the principalship has become markedly more female, with women representing 54 percent of all principals in 2016, compared with just 25 percent in 1988. Principals’ level of experience has fallen on average, especially in high-need schools.
The report also shows growing racial and ethnic gaps between principals and the students they serve. “We have a school leadership corps that is nearly 80 percent white and a student body that is only 53 percent white,” observed Lindsay. “The context of school leadership has changed significantly and to address these patterns, schools and districts should reconsider their human resources policies and practices.”
To meet the needs of growing numbers of marginalized students, the report calls for principals to develop an “equity lens,” defined as ensuring fair, just, and nondiscriminatory treatment of all students, the removal of barriers, the provision of resources and supports, and the creation of opportunities with the goal of promoting equitable outcomes.
Further research is needed, the authors write, to better understand the mechanisms linking principal race and ethnicity to student and teacher outcomes, so that the skills, expertise, practices, or other qualities diverse principals bring to the job might become the focus of preservice and in-service supports for an overwhelmingly white principal workforce. The study calls for a major investment in high-quality research methods and data collection to develop a more cohesive body of findings on school principals.
The report is the first of three research syntheses commissioned by Wallace. A second report will examine the role of the assistant principal, a new area of inquiry that has emerged from the foundation’s work over the past 15 years. A third will look at the characteristics and outcomes of effective principal preparation programs, building on what has been learned since Preparing School Leaders for a Changing World: Lessons from Exemplary Leadership Development Programs was published in 2007. Both reports are expected to be released this year.
To read How Principals Affect Students and Schools: A Systematic Synthesis of Two Decades of Research and other reports on school leadership, visit the Wallace Knowledge Center.
Based in New York City, The Wallace Foundation is an independent national philanthropy whose mission is to foster equity and improvements in learning and enrichment for young people, and in the arts for everyone. Current areas of interest include school leadership, expanding and diversifying audiences for the arts, social and emotional learning, summer learning, arts education, and afterschool. Wallace aims to help solve problems facing the fields in which it works, benefiting both the organizations it funds directly and the broader field by developing credible, useful knowledge to inform policy and practice nationwide. Research commissioned by and produced by the foundation is available without charge from the Knowledge Center at www.wallacefoundation.org.