Recent years have seen a surge in the number of assistant principals and the percentage of schools with them, but despite its growing presence, the AP role is often overlooked. With the proper training and development, APs could make more powerful contributions to important efforts including advancing educational equity, improving schools and fostering principal effectiveness. That is the central conclusion of this report, which is based on a synthesis of 20 years of research on assistant principals in U.S. public schools (79 studies published since 2000) as well as analyses of data from national and state sources.   

The authors, researchers at Vanderbilt University and Mathematica, find that the number of APs jumped from about 44,000 to 81,000 over the 25-year period from the 1990-1991 school year to the 2015-2016 school year, while the percentage of schools with APs rose significantly as well—from about one-third to one-half of public schools. The job of these APs is complex, generally including a mix of instructional leadership, management and student discipline responsibilities, and the amount of time APs devote to the tasks varies, often at the discretion of the principal. APs typically work with students, teachers and families, and there is some evidence that effective APs could help improve academic outcomes and school climate, and, especially in handling student discipline, foster culturally responsive environments.

Along with the expanded number of APs has come substantial growth in the proportion of principals with AP experience, suggesting that a stint as an AP has become an increasingly common stop along the pathway to the principalship.

Still, not all APs are assigned responsibilities that best prepare them to become principals, and there are numerous other indications that the role needs new consideration. For one thing, the study finds puzzling racial and gender disparities in the school leadership pipeline. Across six states the researchers examined, 24 percent of APs were people of color vs. 19 percent of principals and 34 percent of students; women, meanwhile, accounted for 77 percent of the teacher workforce and 52 percent of the AP and principal workforce. Evidence of the reasons for these disparities is limited, but some research suggests that explanations could include hiring discrimination and less access to mentoring, especially for female APs of color. Competing family responsibilities may also play a role for women in general.

The researchers also found evidence that AP evaluation may often be unclear and untethered from assistant principal roles and responsibilities. Moreover, the assistant principalship has been seriously under-studied, with little or no evidence on such matters as how APs are assigned to schools, how well preservice programs prepare future APs, and whether APs are placed in the schools where they are most needed.  

Taken together, the findings suggest the need for greater attention to the AP role by both the education community and researchers. The authors offer a number of suggestions to that end, including identifying and removing barriers to leadership advancement for educators of color and women; developing job standards consistent with the AP’s function as stepping-stone to the principalship; ensuring that principals have the skills to mentor APs and delegate tasks to them; and carrying out a research agenda to narrow gaps in understanding about the role.

This report is one of three research reviews commissioned by Wallace to provide updated syntheses of what is known about important topics in school leadership. A report published earlier in 2021 looks at principals and their impact on schools and students, updating a 2004 research review. A forthcoming report looks at school leader preparation and professional development, updating a 2007 study of the subject.


"This research confirms the need to reculture the assistant principalship in perceptions and practices. Assistant principals are poised and ready to assume deeper leadership roles in our schools. This report provides a roadmap for us to elevate the position, increase the impact of the school leadership team, and address the systems and structures that can enable assistant principals to offer their true strengths and full potential in the pursuit of increased student achievement and success."

—Beverly J. Hutton, Ed.D., NASSP chief programs officer
National Association of Secondary School Principals 

"School and student success depends on strong leadership teams, and that includes the role of the assistant principal. This report provides a strong foundation for what we know about the assistant principal role and more important, what we must learn to ensure that schools have the strong leadership that they need."     

—L. Earl Franks, Ed.D., CAE, executive director
National Association of Elementary School Principals 

​​"This research recognizes assistant principals’ complex role and gives it the attention it deserves by highlighting assistant principals as leaders. The report addresses the pipeline needed to strengthen one’s administrative skills, resulting in a distributed leadership model where assistant principals contribute to and share school leadership responsibilities beyond day-to-day management and discipline."

—Debra Paradowski, associate principal
 Arrowhead Union High School, Hartland, Wisc.
NASSP National Assistant Principal of the Year, 2020

 Points of Interest

  • A major study of assistant principals synthesizes recent research and analyzes data from national and state sources, concluding that the education field needs to “focus more on this increasingly prevalent yet often overlooked role.”
    Major report on #assistantprincipals “highlights the need to focus more on this increasingly prevalent yet often overlooked role.”
  • Nationally, the number of assistant principals, along with the percentage of schools with them, has increased markedly over the past 25 years, according to a comprehensive examination of the research and national/state data on APs. Today, about half of U.S. public schools have APs, up from one-third 25 years ago.
    Nationally, the number of #assistantprincipals and the percentage of schools with them have increased markedly over the past 25 years. Today, about half of U.S. public schools have APs, according to a study.
  • The assistant principal job is an increasingly common stepping-stone to the principalship, a study finds. Today, three-quarters of principals have AP experience, up from one-half roughly a generation ago, according to an analysis of national data.
    Report: The #assistantprincipal job is an increasingly common stepping-stone to the principalship. Today, three-quarters of principals have AP experience, up from one-half roughly a generation ago.

 Supplementary Materials

  • Figure ES.1. Nationally, the percentage of schools with assistant principals has increased over the past 25 years
  • Figure III.6 The percentage of principals with experience as an assistant principal has increased over the past 25 years
  • The Role of Assistant Principals: Evidence and Insights for Advancing School Leadership
  • The Role of Assistant Principals: Evidence and Insights for Advancing School Leadership,