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The principal perspective: full report

Lean on Me. Principal Skinner from The Simpsons. Blackboard Jungle. Articles and books have been written and movies have been made about principals, with the image of a principal as everything from an ineffective, out-of-touch authoritarian to a hard-charging leader capable of single-handedly turning around a low-performing school. What impact do principals actually have on a school? Can they turn schools around? If so, what do they do to achieve such success?

These are important questions, but until recently there has been very little research done on the principal’s role. Fortunately, that has begun to change due to increased accountability and more data on the effect of principals. Some researchers now say that principals are second only to teachers in their impact on student achievement (The Wallace Foundation 2012).

Recent studies have examined the relationship between principals and student outcomes, and attempted to identify what characteristics and qualifications are needed to be an effective principal, whether that’s providing staff with the resources and support they need, hiring and retaining the best talent, setting expectations for instruction, or simply gaining more experience. So what has the research found out? Let’s take a look.

What the research says: an overview
The job of principal has changed dramatically. Principals are now more than ever focused on student achievement while still retaining their traditional administrative and building manager duties. Because of this, principals typically work 10 hour days and many believe the job is just not “doable” as it is configured now (Usdan, McCloud and Podmostko 2000).
Principals impact their students’ outcomes, particularly at the most challenging schools. When looking at factors within a school it is estimated that principals are second only to teachers in their impact on student achievement (Seashore-Louis, et al. 2010). A highly effective principal can increase his or her students’ scores up to 10 percentile points on standardized tests in just one year (Waters, Marzano and McNulty 2003). Principals can also affect other student outcomes including reducing student absences and suspensions, and improving graduation rates. Principals in low-achieving or high poverty, minority schools tend to have a greater impact on student outcomes than principals at less challenging schools (Leithwood, et al. 2004, Seashore-Louis, et al. 2010). Unfortunately, principals typically transfer to less challenging schools as they gain experience (Beteille, Kalogrides and Loeb 2011).

Principal turnover adversely impacts schools. Although gains in student achievement temporarily slow whenever there is a new principal, the impact is felt more at the most challenging schools. In these schools, the new principal is more likely to have less experience and be less effective than a new principal at a less challenging school, often resulting in a longer, more pronounced slowdown of achievement gains. The reason for the staffing difference is that many principals gain their initial experience at challenging schools, then transfer to easier-to-manage schools as those positions open up. A study of one large urban district found that principals’ second or third schools typically enrolled 89 percent fewer poor and minority students than their first position (Beteille, Kalogrides and Loeb 2011, Miller 2009).

Effective principals retain and recruit effective teachers. Teacher turnover rates typically increase (regardless of whether teachers leave voluntarily or involuntarily) when there is a change in principals, no matter if the principals are effective or ineffective (Beteille, Kalogrides and Loeb 2011). However, less effective teachers tend to leave under an effective principal, while more effective teachers tend to leave when the school is taken over by an ineffective principal. Furthermore, effective principals are more likely to replace teachers who leave with more effective teachers (Beteille, Kalogrides and Loeb 2011, Branch, Hanushek and Rivkin 2012, Portin, et al. 2003).

Principals become more effective as they gain more experience. Just as teachers become more effective with experience, so do principals, especially in their first three years (Clark, Martorell and Rockoff 2009).  Furthermore, no matter how effective a principal was at his or her previous school, when he or she transfers to a new school it takes approximately five years to fully stabilize and improve the teaching staff as well as fully implement policies and practices to positively impact the school’s performance (Seashore-Louis, et al. 2010). Effective principals still make significant improvements in their first few years; however, their effectiveness definitely increases over time. Unfortunately, schools that serve the most challenging students are more likely to be led by less experienced principals than more advantaged schools (Loeb, Kalogrides and Horng 2010). Even so, although both effective and ineffective principals typically transfer to less challenging schools within a district, effective principals are more likely to stay at challenging schools longer than their ineffective colleagues (Branch, Hanushek and Rivkin 2012).

Being an instructional leader is a hallmark of effective principals.
Effective principals are more likely to provide their teachers with the support and motivation they need to be effective teachers. For example, although both effective and ineffective principals claimed to frequently observe their teachers, effective principals make more unscheduled observations and provide immediate feedback (The Wallace Foundation 2012). 

This report will examine each of the above points in more detail.

The job of principal has changed dramatically

The role of principal has changed dramatically over the past couple of decades (Levine 2005). It wasn’t too long ago that a principal’s primary tasks were limited to making sure that the buses ran on time, ordering supplies, and addressing personnel issues (Usdan, McCloud and Podmostko 2000). Nowadays, a principal’s main responsibility is student learning (The Wallace Foundation 2012, Usdan, McCloud and Podmostko 2000). Since the administrative and building management duties have not disappeared, the average principal now puts in over 10 hours a day (Usdan, McCloud and Podmostko 2000). 

Today, principals must spend much more time in classrooms than in the office, and they are asked to focus on curriculum and instruction as well as collecting, analyzing, and using data to improve student achievement (The Wallace Foundation 2012, Usdan, McCloud and Podmostko 2000). On top of that, they are expected to rally students, teachers, and the community to help achieve these goals (Usdan, McCloud and Podmostko 2000). It is no surprise that principals increasingly say the job is simply not doable (Usdan, McCloud and Podmostko 2000).

In response to these new responsibilities, the Interstate School Leaders Licensure Consortium (ISLLC) created a set of standards for principals. ISLLC, a consortium of national education leadership organizations including the National Association of Elementary School Principals, the National Association of Secondary School Principals, the Council of Chief State School Officers and several others, created these standards in 1996 and most recently revised them in 2008. Among other things, the standards recommend that principals have knowledge of (Grossman 2011):

  • principles of effective instruction
  • curriculum design, implementation, evaluation, and refinement
  • principles related to implementing a strategic plan
  • information sources, data collection, and data analysis strategies
  • how to inspire others with the vision that all children can learn at high levels.

This is not an exhaustive list, and ISLLC standards are simply a broad set of guidelines that states can use as a model for developing or updating their own standards. However, they do show that the duties principals need to perform are much different than those performed by principals in the last century. As the report will show, these new requirements are also essential skills principals need to improve student achievement, especially when leading low-performing schools.

Principals significantly impact students’ outcomes, particularly at the most challenging schools

Principals cannot simply ride into a school on a white horse and turn around a low-performing school by themselves. However, research strongly suggests they are a key ingredient to improving a school’s performance, especially low-achieving schools and those schools serving traditionally disadvantaged students. As the Wallace Foundation stated, “There are virtually no documented instances of troubled schools being turned around without intervention by a powerful leader” (Leithwood, et al. 2004). 

So exactly how much does a principal impact student outcomes, and does the type of school make a difference? Furthermore, does the impact differ depending on the location of the schools, the students in the school, or the type of school they lead?

The Wallace Foundation, which has been examining principal effectiveness over the past decade, has declared that principals are second only to teachers as the most influential in-school factor in student achievement (Leithwood, et al. 2004, Seashore-Louis, et al. 2010). Out of all school-level factors,  teachers are estimated to account for more than a third of the variation in a school’s achievement (Seashore-Louis, et al. 2010). But the Wallace Foundation calculated that principals represent nearly 25 percent of the variation in a school’s achievement (Seashore-Louis, et al. 2010). This is because while individual teachers have a tremendous impact on their students’ achievement, it takes multiple in-school factors coming together to significantly improve student achievement on a large scale (The Wallace Foundation 2012).  Principals are in the unique position to bring those factors together.

Overall impact on student outcomes

Several researchers show that principals play a significant role in student achievement. One study found that an average school led by a highly effective principal performed 10 percentage points higher than if that school was led by an average principal (Waters, Marzano and McNulty 2003). A more recent study found that, based on value-added scores, having a highly effective principal increased students’ achievement from the 50th percentile to between the 54th and the 58th percentiles in just one year, depending on the type of analysis conducted (Branch, Hanushek and Rivkin 2012). Such impact on student achievement is similar to that of reducing class size by five students (Branch, Hanushek and Rivkin 2012, Rivkin, Hanushek and Kain 2005). (Keep in mind that a principal’s impact differs depending on the level of the school, the demographics of the students in the school, and the initial performance of the students.)

There is some evidence that principals not only impact academic achievement, but other outcomes as well:

  • When examining principals’ impact on the number of days students miss, researchers found that student absences were lower in schools led by effective principals than when led by less effective principals. Furthermore, the impact was even greater in low-performing and high-poverty schools than in high-performing and low-poverty schools (Branch, Hanushek and Rivkin 2012, Clark, Martorell and Rockoff 2009).
  • Over the long term, principals can impact a school’s graduation rate. A high school led by a highly effective principal would have a graduation rate nearly 3 percentage points higher than a high school led by an average principal (Coelli and Green Forthcoming). But it takes time for even highly effective principals to have such an impact. On average, the effect of principals on their school’s graduation rate starts in their second year at the school. It’s not until a principal is at a school for at least four years that the full impact is evident (Coelli and Green Forthcoming).

There is limited research on the  effect of principals on non-academic outcomes. So the impact of principals on many other outcomes still needs to be explored.

Greater impact on the most challenging schools

Principals have more of an impact on student achievement in the most challenging schools – specifically, high-poverty and high-minority schools as well as low-performing schools -- than principals in less challenging schools. For example, a study by the CALDER Center found that the impact of principals, as measured by the value-added scores based on student test scores, was nearly twice as large in high-poverty schools as in low-poverty schools (Branch, Hanushek and Rivkin 2012).  Furthermore, their 2009 study also found the impact to be greater in large high-poverty schools than in large low-poverty schools, which has been found in other studies as well (Branch, Hanushek and Rivkin 2009, Clark, Martorell and Rockoff 2009, Loeb, Kalogrides and Horng 2010). Similar results were found for high-minority and low-performing schools as well. See a graph illustrating these effects.


Greater impact on elementary schools

Principals also have more of an impact at the lower grades. As a matter of fact, principals have the greatest impact in elementary schools, less over middle schools, and the least over high schools (Leithwood, et al. 2004, Seashore-Louis, et al. 2010). 

Although it is not clear why, it may be due to the fact that middle and high schools typically have more teachers than elementary schools. As a result, principals in these schools are less likely to provide direct supervision and support to their teachers (Seashore-Louis, et al. 2010). As with leaders in other organizations, a principal’s influence is difficult to maintain as the organization expands, and (as a later section will show) providing such support is an important factor in principal’s effectiveness.

Another reason principals may have less impact at the middle and high school levels is that teachers in these schools are usually subject-specific. Consequently, principals are unlikely to have the subject specific knowledge necessary to provide the same instructional support as elementary school principals (Leithwood, et al. 2004, Seashore-Louis, et al. 2010), and instructional support is key to principal effectiveness. While middle and high school principals should be able to rely on their department heads to provide such support, department heads don’t seem to be filling in that gap (Leithwood, et al. 2004, Seashore-Louis, et al. 2010). Finally, elementary school principals may have more impact because they spend 60 to 80 percent of their time in the classroom, while the average high school principal’s job has not fully transitioned into a role as the school’s instructional leader (Grigsby, et al. 2010). However, even though elementary school principals have the most impact, as we saw in the first section, principals at all levels still significantly affect school performance.

Principal turnover adversely impacts schools

Turnaround strategies and principals
If a principal truly is one of the key ingredients to turning around a school, how do we evaluate federal and state turnaround strategies that involve removing or replacing the school’s principal?

The research that exists seems to suggest that we evaluate strategies based on two factors: the effectiveness of the principal and the time allowed for a turnaround to occur.

First, a turnaround strategy that replaced an ineffective principal with an effective one could have a significant impact, because we know that effective principals can have a measurable impact on student achievement. Since teachers are an important part of a principal’s strategy, effective teachers would be key to turning around a struggling school as well.

The time given for a turnaround to take place would also be key. The research shows that time affects principals’ effectiveness in two ways. First, a rookie principal makes the most dramatic increases in his or her own effectiveness in the first one to two years of being a principal. A replacement principal would ideally have at least three years of experience and have a record of success in a previous school.

Second, even an effective principal with experience needs some time to become as effective in a new setting. Looking at value-added data, it seems that a highly effective principal needs at least one to two years to become as effective in a new school.

Finally, research also shows that it takes a highly effective principal about five years to fully impact a school’s performance, particularly in terms of putting in place a staff whose vision is aligned with the principal’s and to have fully implemented policies and practices to improve student achievement. The five years has less to do with scores and more to do with institutionalizing the changes the principal had made that improve student achievement. Ideally, then, a turnaround strategy would identify highly effective principals and provide the proper incentives and support for them to implement and institutionalize improvements over five years.
Just as a principal’s presence can improve student achievement, a principal’s departure can  have the opposite effect. In a study of Miami-Dade County Public Schools (MDCPS) researchers found that students attending schools with a new principal made lower achievement gains in math than they had been under the previous principal (Beteille, Kalogrides and Loeb 2011). This was true whether the incoming principal had no prior experience or if he or she was a temporary or interim principal (Beteille, Kalogrides and Loeb 2011). Yet, if the new principal at the school had previous experience at another school, the negative impact was minimized (Beteille, Kalogrides and Loeb 2011). Similar results were found when studying principals in North Carolina as well (Miller 2009).

Tenure length
Research shows it takes approximately five years to put a teaching staff in place as well as fully implement policies and practices that will positively impact the school’s performance (Seashore-Louis, et al. 2010). Keep in mind, effective principals still make significant improvements in their first years as well (Coelli and Green Forthcoming, Portin, et al. 2003, Seashore-Louis, et al. 2010).

Yet the average length of a principal’s tenure is three to four years for the average school (Seashore-Louis, et al. 2010). In low-performing schools and schools serving disadvantaged students, the average tenure is even shorter. For example, in MDCPS, principals in the lowest performing schools had an average of 2.5 years of experience at that school -- less than half the average tenure of principals in their highest performing schools (5.1 years) (Loeb, Kalogrides and Horng 2010).

Tenure length varies
While annual turnover rates for principals range between 15 and 30 percent, similar to turnover rates of managers in other professions, turnover rates at more challenging schools are on the higher end of that spectrum (Beteille, Kalogrides and Loeb 2011, Boyd, et al. 2008, Clark, Martorell and Rockoff 2009). For example, the principal turnover rate in MDCPS  is 22 percent, similar to that found in other large urban districts such as Milwaukee (20 percent), San Francisco (26 percent) and New York City (24 percent). However, within MDCPS the turnover rate rises to 28 percent for the district’s highest-poverty schools, compared to an 18 percent turnover rate in their lowest-poverty schools (Beteille, Kalogrides and Loeb 2011). Similar results were found examining New York City schools (Clark, Martorell and Rockoff 2009). And when challenging schools lose an effective principal, that principal is likely to be replaced by a less-experienced and less-effective principal (Beteille, Kalogrides and Loeb 2011, Branch, Hanushek and Rivkin 2012). See graphs illustrating these effects.

The good news is that the most effective principals are more likely to remain at a school for at least three years, even at challenging schools, than the least effective principals (Branch, Hanushek and Rivkin 2012). At more challenging high-poverty schools, 67 percent of the most effective principals return for a fourth year (Branch, Hanushek and Rivkin 2012). In contrast, less than two-thirds of the least effective  principals return to those schools (Branch, Hanushek and Rivkin 2012). So although more challenging schools have greater principal turnover, the most effective principals have longer tenures than ineffective principals (Branch, Hanushek and Rivkin 2012, Seashore-Louis, et al. 2010).

What do we mean by "effective"?
In this paper, an “effective” principal is defined as one whose students make greater than average gains than similar students in other schools. Those gains are calculated using value-added growth models, which compare the change in student achievement from one year to the next of a large group of students with similar demographic characteristics and prior achievement. Students who attend a school led by a principal with high value-added scores would, on average, make greater achievement gains than if they attended a school led by a principal with lower value-added scores. In contrast, students attending a school led by an ineffective principal would, on average, make fewer gains than if they attended a school led by an average effective principal. (For a fuller explanation of value-added models and scores, see “Measuring student growth.”)

Effective vs. ineffective principals
In general, ineffective principals exhibit more turnover than effective principals. While there is little indication that ineffective principals leave the profession at a higher rate than effective principals, there are indications that they change jobs more often. While ineffective principals stay for shorter periods at challenging schools, they also stay for shorter periods at all types of schools. Given the negative impact principal turnover has on student achievement, ineffective principals’ short tenures are another way they negatively impact schools.

It is noteworthy, then, that principals who leave rarely leave the profession – they simply transfer to a less challenging school (Branch, Hanushek and Rivkin 2012). While in other professions managers often leave after periods of poor performance, the vast majority of principals who leave a school – even ineffective ones -- do so voluntarily and typically transfer within the district (Beteille, Kalogrides and Loeb 2011, Branch, Hanushek and Rivkin 2012). For instance, nearly 80 percent of  the least effective principals in high-poverty schools in Texas continue to be  principals in the state (Branch, Hanushek and Rivkin 2012). While ineffective principals are leaving more challenging schools, they are simply transferring to less challenging and higher performing schools where their ineffectiveness is masked by their new school’s already-high performance. To put it simply, while students in schools led by ineffective principals may be high achieving, they could be even higher achieving if they were led by an average or highly effective principal instead.

Why turnover happens and what might decrease it
The major reason for principal turnover, especially in high-poverty, high-minority schools, is the desire to lead less challenging schools, which often translates into principals transferring into higher achieving schools that tend to enroll fewer poor and minority students (Beteille, Kalogrides and Loeb 2011, Clark, Martorell and Rockoff 2009, Loeb, Kalogrides and Horng 2010). For example, in Miami-Dade County Public Schools (MDCPS) a principal’s second or third school had 89 percent fewer poor and minority students than their first school, as well as fewer low-achieving students (Beteille, Kalogrides and Loeb 2011). However, for principals whose race is the same as the largest student racial group in the school this is less likely to be the case (Loeb, Kalogrides and Horng 2010). 

When researchers looked more deeply into why principals transfer to less challenging schools it turns out that a principal’s desire had less to do with the student demographics than working conditions (Loeb, Kalogrides and Horng 2010). Schools that serve a large number of low-income and/or minority students tend to have more difficult working conditions such as inferior facilities, fewer instructional resources, and less qualified staff among others. Most principals are not paid extra to work in more difficult conditions, The only way they can mitigate these conditions is by transferring to a school that is less demanding schools that tend to be lower-poverty schools (Beteille, Kalogrides and Loeb 2011, Loeb, Kalogrides and Horng 2010).  So principals often use more challenging schools as stepping stones to lead less challenging schools as they gain more experience (Beteille, Kalogrides and Loeb 2011, Clark, Martorell and Rockoff 2009, Loeb, Kalogrides and Horng 2010). 

Finally, the five-year mark is important. The probability of principals leaving their current school increases each year for the first five years of tenure within a school and decreases for principals with tenures of at least six years (Branch, Hanushek and Rivkin 2012).

Turnover’s implications
Taken together, research shows that stable leadership at a school has a positive impact on a school’s performance. Unfortunately, our lowest performing schools serving our most disadvantaged students have the least stable leadership. This has led to many of these schools being led by less experienced, less qualified, and less effective principals (Loeb, Kalogrides and Horng 2010). To make matters worse, once principals serving these schools gain experience and become more effective, they prefer to transfer to schools that are higher-performing and serve fewer disadvantaged students. Such frequent turnover negatively impacts student achievement as well as teacher turnover. Providing a more stable, effective school leadership for our most disadvantaged and low-performing school would likely have a significant impact on the outcomes of the students attending those schools.

The negative impact of principal turnover also highlights the importance of hiring effective principals for the most challenging schools in the first place. Since principal turnover negatively impacts student achievement for multiple years, hiring an ineffective principal can negatively impact student achievement for several years, even if he or she is replaced by an effective principal.

Such findings have implications for federal and state turnaround policies, which often offer the option of replacing the principal. However, consistently replacing a principal can actually harm a school, since high principal turnover would negatively impact the school’s performance (Beteille, Kalogrides and Loeb 2011). On the other hand, such a strategy can have a significant impact on the school’s performance if the new principal is highly effective and is given at least five years to improve the quality of the teaching staff and implement policies and practices focused on high achievement for all students. Simply replacing a principal in a failing school may actually do more harm than good; but replacing an ineffective principal with a highly effective principal while providing incentives for the new principal to remain at the school for more than five years could have a dramatic impact on the school’s achievement and other outcomes.

Effective principals improve teacher quality

Now that we know that principals impact schools, how do they do it? A main way is through increasing the effectiveness of their teachers. They do this by retaining and recruiting effective teachers, and by providing teachers the resources and support they need to maximize their impact on student achievement.

As we will show in this section, teacher turnover rates increase when there is a change in principals, no matter if the principals are effective or ineffective (Beteille, Kalogrides and Loeb 2011, Miller 2009). However, the less effective teachers are more likely to leave a school when taken over by an effective principal and they tend to be replaced by more effective teachers. In contrast, ineffective principals see more of their effective teachers leave (Beteille, Kalogrides and Loeb 2011, Branch, Hanushek and Rivkin 2012). The next section will go into more detail on how principals can increase their teachers’ effectiveness by providing instructional support.

Keep in mind that isolating a principal’s impact on recruiting and retaining effective teachers is difficult due to a multitude of outside influences. So while these results should be viewed with some caution, they still provide some insight into the impact principals have on the effectiveness of their teaching staff.

Teacher turnover increases with a new principal

Teacher turnover increases whenever there is a new principal, no matter how effective the principal is. Overall, the odds a teacher will leave a school are 17 percent higher when a new principal enters (Beteille, Kalogrides and Loeb 2011). And teacher turnover increases for two years following the departure of the previous principal (Miller 2009).

But simply having a new principal doesn’t provide the full story on why teachers leave a school. The previous experience of the incoming principal affects a new principal’s impact on teacher turnover (Beteille, Kalogrides and Loeb 2011). For example, teacher turnover is greater when the new principal has little or no previous experience as a principal (Beteille, Kalogrides and Loeb 2011). Moreover, teacher turnover is even greater under temporary or interim principals (Beteille, Kalogrides and Loeb 2011).

As principals gain experience in a particular school, teacher turnover decreases. For example, compared to a new principal, the teacher turnover rate is 1 percent point lower in schools where the principal has five or more years of tenure. Effectively, this means around 10 percent fewer teachers leave (Clark, Martorell and Rockoff 2009, NCES 2011). And the odds of teacher turnover are reduced 4 percentage points for every extra year a principal remains at a school (Beteille, Kalogrides and Loeb 2011). So, more stable leadership at a school leads to a more stable teaching staff, which can contribute to a more effective teaching staff.

However, a new principal may come into the school expressly to remove ineffective teachers and replace them with more effective teachers. Some studies have shown that effective principals are more likely to aggressively weed out ineffective teachers as well as recruit new teachers more carefully (Portin, et al. 2003). More effective principals also lose fewer effective teachers (Branch, Hanushek and Rivkin 2012), probably by creating a more favorable working environment (The Wallace Foundation 2012). So effective principals are more likely to improve their teaching staff by retaining and recruiting effective teachers.

Conversely, the least effective principals lose a greater share of their most effective teachers. In fact, ineffective principals not only drive effective teachers out of their school; they drive their most effective teachers out of their district (Branch, Hanushek and Rivkin 2012). To make matters worse, the impact is greater at high-poverty schools. In these schools, effective teachers are more likely to leave a school led by an ineffective principal (Beteille, Kalogrides and Loeb 2011). Since high-poverty schools typically have less favorable working conditions, it makes sense for effective teachers to leave a school where the principal is not making it any easier. 

Principals impact their teachers’ performance

Effective principals not only recruit and retain effective teachers, they also improve the effectiveness of the teachers they do have (Seashore-Louis, et al. 2010). They do this by improving teachers instructional abilities (Robinson, Lloyd and Rowe 2008, Seashore-Louis, et al. 2010). In general, effective principals are strong instructional leaders who consistently provide constructive feedback to new and veteran teachers alike on how to improve instruction, which will be expanded upon in a later section. However, it takes time for principals to have such an impact -- which is one reason why principal turnover has an adverse affect on schools.

Even teacher absences are lower under more effective principals (Miller 2009). Furthermore, teacher absences decline as a principal’s effectiveness increases (Miller 2009). A possible explanation is that teacher morale is higher in schools led by effective principals, and happier teachers are less likely to be absent (Miller 2009). As such, students spend more time being taught by an effective teacher rather than a substitute.

Principals become more effective as they gain more experience

Finally, what makes an effective principal? Unlike teachers, where research shows a strong correlation between a combination of certain teacher characteristics and student outcomes (Center for Public Education 2005), it is less clear which principal characteristics are associated with higher student outcomes. However, some reliable research is starting to emerge.

The impact of an effective principal
Schools that have highly effective principals:
  • Perform 5 to 10 percentage points higher than if led by an average principal
  • Have fewer student and teacher absences
  • Have effective teachers stay longer
  • Typically replace ineffective teachers with  more effective teachers
  • Have principals who are more likely to stay for at least three years
  • Have principals who have at least three years of experience at that school
Effective principals have the most impact in elementary schools and in high-poverty, high-minority schools.

Two studies by the CALDER Center provide important insights into what principal characteristics affect student achievement. One study, by Coelli and Green, examined principals in New York City, while another study, by Branch, Hanushek, and Rivkin, examined principals in Texas. Other studies by various organizations such as the Wallace Foundation have also examined the connection between principals and student outcomes. All the studies have come to a fairly similar conclusion: that principals become more effective with experience.

Experience as a principal

Research is quite clear that new principals become more effective as they gain experience (Beteille, Kalogrides and Loeb 2011, Branch, Hanushek and Rivkin 2012, Clark, Martorell and Rockoff 2009, Coelli and Green Forthcoming, Seashore-Louis, et al. 2010). Just like teachers, principals make significant improvement in their first couple of years, then make more modest improvements in the following years (Clark, Martorell and Rockoff 2009, Coelli and Green Forthcoming). For example, one study found the difference in the effectiveness of a first year principal and a third year principal to be similar to the difference in the effectiveness of a first year teacher and a second year teacher (Boyd, et al. 2008, Clark, Martorell and Rockoff 2009). Other researchers have found the difference to be a bit smaller, but still significant (Branch, Hanushek and Rivkin 2012).

Many qualifications have little effect

What about other characteristics, such as previous experience in other jobs or level of education? Surprisingly, very few have shown a relationship to principal effectiveness. Here are some of the characteristics that have been studied:

Years of experience as a teacher or an assistant principal: no. When it comes to principals, almost all have previous experience as a teacher. Many have previous experience as an assistant principal as well. But the amount of time served in these positions does not seem to impact principals’ effectiveness. A study based in New York City found that the number of years a principal was a teacher or was an assistant principal had no bearing on how effective he or she was as a principal (Clark, Martorell and Rockoff 2009). However, a new principal who had previously been an assistant principal at the same school was initially more effective than other new principals (Clark, Martorell and Rockoff 2009). The impact was short-lived; other new principals were just as effective after gaining experience (Clark, Martorell and Rockoff 2009).

Education: no. Since most principals in the sample studied have a M.A. degree, it is not possible to examine the impact of having a M.A. degree vs. not having one. However, researchers were able to examine the impact of a principal’s college. They found that (unlike teachers) the selectivity of a principal’s college, whether undergraduate or graduate,  had no bearing on his or her effectiveness as a principal (Clark, Martorell and Rockoff 2009).

Principal training programs: sometimes. There is no clear consensus on the impact of principal preparation programs. Such programs differ dramatically not only across states but within states as well. So it really isn’t feasible for researchers to evaluate the general impact of principal preparation programs on effectiveness. However, researchers have evaluated specific programs’ impact on the effectiveness of principals trained by them, and have found mixed results. It has shown that some programs consistently turn out effective principals: For example, graduates from New York City’s Aspiring Principal Program (APP) improve their school’s performance relative to the improvement other principals would have made (Clark, Martorell and Rockoff 2009). Other programs typically do not.

Professional development: sometimes. The impact of principal professional development programs on effectiveness is quite mixed (Boyd, et al. 2008). There are some programs in New York City, such as the Cahn Fellows program, that have been shown to improve the effectiveness of already effective principals (Clark, Martorell and Rockoff 2009). However, when the Wallace Foundation interviewed principals across nine states, most gave their districts low marks for providing quality professional development (Seashore-Louis, et al. 2010).

So does anything other than experience consistently make a difference? It turns out that principal effectiveness has less to do with resume qualifications and more to do with actions taken on the job. Fortunately, researchers, particularly at the Wallace Foundation, have been looking at what actions effective principals take that ineffective principals don’t.

Being an instructional leader is a hallmark of effective principals

Principal effect is related most to what they do to specifically support academic learning. While individual actions contribute to a principal’s effectiveness, it is important to keep in mind that no single action is consistently linked to improved student outcomes (Seashore-Louis, et al. 2010).

Characteristics of an effective principal
Principals who are highly effective are more likely to:
  • Have at least more than three years of experience overall
  • Have at least three of experience at that school
  • Share leadership responsibilities, rather than just delegate paperwork
  • Have a clear sense of instructional goals
  • Give ongoing, informal feedback and support toward those goals
  • Conduct unannounced, informal teacher evaluations or classroom visits and give feedback afterward
  • Have school boards and superintendents who exhibit a clear vision of what constitutes a good school and create a framework that gives principals both autonomy and support to reach those goals

Effective principals typically:
Set goals and provide a vision. The foundation for being an effective principal is establishing a school-wide vision and commitment to high standards and success of all students (The Wallace Foundation 2012). This is essential in creating a culture of academic success for all students within a school (The Wallace Foundation 2012). Doing so means the principal spells out high  expectations and rigorous learning goals all students are expected to meet (The Wallace Foundation 2012).

Not only is setting goals important, but instilling the belief in teachers that they can reach these goals is, too (Seashore-Louis, et al. 2010). Principals who are able to inspire their teachers in this way have a small but positive impact on student achievement (Seashore-Louis, et al. 2010).

Share leadership. The most effective principals do not do it alone. They share leadership responsibilities with their teachers and other administrators (Seashore-Louis, et al. 2010). This does not mean that principals sacrifice their authority over a school. To the contrary, principals that effectively share leadership still actively monitor and support those tasks to ensure everyone is progressing towards the school’s goals (Seashore-Louis, et al. 2010, The Wallace Foundation 2012). In schools that had high levels of such shared leadership, the principals rarely assigned purely administrative work to teachers or other professionals in the school (Seashore-Louis, et al. 2010). So, shared leadership is primarily focused on meeting a school’s goals, not simply spreading out the workload.

Are instructional leaders. Principals that provide teachers with instructional leadership improve student achievement (Seashore-Louis, et al. 2010). As a matter of fact, a principal’s instructional leadership has about three to four times more impact on student achievement than “transformational leadership,” where principals focus on motivation and improving the morale of their teachers (Robinson, Lloyd and Rowe 2008). Principals show instructional leadership by setting a culture within the school that supports continual professional learning and by taking explicit steps to support individual teachers (Seashore-Louis, et al. 2010).

There are several ways teachers say principals provide instructional support:

  • by emphasizing the value of research-based strategies and applying them effectively to their own school (Seashore-Louis, et al. 2010).
  • by encouraging teacher collaboration (The Wallace Foundation 2012)
  • by providing more time for teacher planning (The Wallace Foundation 2012)

Principals with these characteristics are rated higher in supporting improved instruction and this in turn improves student achievement (The Wallace Foundation 2012).
Principals also provide instructional support by monitoring their teachers’ work. But The Wallace Foundation found a great contrast between effective and ineffective principals in how they do this. (The Wallace Foundation 2012). Effective principals provide support by having ongoing and informal interactions with teachers throughout the year; they don’t simply wait for the annual formal evaluations to provide feedback to their teachers (The Wallace Foundation 2012).  While both sets of principals said they frequently visit classrooms, effective principals made more frequent and spontaneous observations of classroom instruction so they could provide direct and immediate feedback to help improve their teachers’ performance, no matter if  the teacher was a  novice or a veteran (Seashore-Louis, et al. 2010). In contrast, ineffective principals still made classroom visits, but they were usually planned in advance and they rarely provided feedback to teachers afterward (Seashore-Louis, et al. 2010).

The Wallace Foundation found that principals who were highly rated overall by their teachers ranked high in both giving specific instructional guidance and setting an overall tone of research-based instruction (Seashore-Louis, et al. 2010). And it’s interesting to note that principals rated highly in developing this type of instructional climate were more effective than principals rated highly in “developing an atmosphere of caring and trust” (The Wallace Foundation 2012).

Support from their districts. The principals interviewed by the Wallace Foundation believed that districts can have the greatest role in improving their effectiveness by providing (Seashore-Louis, et al. 2010):

  • Strong guidance on curricular and instructional improvements; and
  • Guidelines to help shape and support motivation for change within their own schools.

In districts that provided such guidance, teachers also rated their principals as more effective instructional leaders (Seashore-Louis, et al. 2010). Furthermore, in high-performing districts, district leaders believed they could develop effective principals by setting expectations for certain leadership practices (Seashore-Louis, et al. 2010). On the other hand, lower-performing districts believed that principal effectiveness was simply attributable to innate personal traits (Seashore-Louis, et al. 2010).

Other research shows that in districts that are highly supportive of their principals, districts and school board leaders exhibit a clear vision of what constitutes a good school and create a framework in which the principal has the autonomy to work with teachers on an improvement agenda with support from the district (Bottoms and Schmidt-Davis 2010). On the other hand, if the district does not provide clear goals or set a vision beyond basic ”test prep,” even the most capable principals will likely be nothing more than caretakers while presiding over schools and teachers that lack direction (Bottoms and Schmidt-Davis 2010).

To set goals and vision, the district must develop a strategic plan that manifests their vision (Bottoms and Schmidt-Davis 2010). By doing so, districts can give principals more autonomy to make decisions within the framework of the strategic plan. At the same time, principals can also be held more accountable for their school’s improvement (Bottoms and Schmidt-Davis 2010). (For more information on doing so, see The Key Work of School Boards, developed by NSBA.)

While autonomy is important, principals need the support of their district to be effective (Bottoms and Schmidt-Davis 2010). Hence, district leaders play an important role on the impact their principals have on their schools by supporting them in the following ways (Bottoms and Schmidt-Davis 2010):

  • Developing tools and processes principals can use to ensure instruction is aligned to the district’s goals and standards.
  • Investing in high quality professional development for principals and teachers.
  • Setting a culture and support for the use of data beyond simple test scores to improve student outcomes. (For more informationon how to do this, visit the Center’s site, Data First, at www.data-first.org.)
  • Regularly identifying promising principal candidates within schools and help create a smooth transition when a principal decides to the leave the school.


Research clearly shows that principals are a key ingredient in the performance of their school, especially if that school enrolls a large number of low performing and/or poor and minority students. Unfortunately, challenging schools are more likely to be led by less experienced and less effective principals even though principals have a greater impact on these schools than on less advantaged schools. Although effective principals tend to remain at these challenging schools longer than ineffective principals, most effective principals transfer to less challenging schools within the district -- not because of the students but because of their desire for better working conditions. Being a principal is hard work but being a principal in a challenging school that lacks much needed resources is even harder so it is no wonder most principals gravitate to less challenging schools, especially since there is typically no difference in pay.

So while the No Child Left Behind Act (NCLB) and other policies of the past decade have mainly focused on teachers to close achievement gaps, research shows that focusing on principals could have a strong impact on turning around low-performing schools and propel student learning. Experienced principals who focus on instructional leadership, give specific, informal feedback to teachers, and share the workload can have a significant, measurable impact on student achievement.

More than a head disciplinarian or a glorified schedule-maker, the principal of today’s school is a leader. While teachers may have the primary influence on student achievement, individual teachers cannot do it alone. An effective principal is needed to maximize teachers’ individual effectiveness as well as the school’s effectiveness as a whole. School boards, educators and policymakers who focus on supporting the principal’s role as instructional leader will be supporting what’s best for students as well.

Questions for School Boards

  • How are principals evaluated for effectiveness?
  • Are evaluations linked to student achievement?
  • Are evaluations linked to the district’s goals and strategic plan?
  • Do all students have equal access to effective or experienced principals?
  • What incentives does your district give principals to lead challenging schools?
  • What kind of professional development does your district provide principals?
  • Has the school board read and discussed the ISLLC standards?
  • How does the district handle ineffective principals?
  • What is the principal turnover rate in your district? How does it vary by school? What could your district do to decrease the turnover rate to the key period of three to five years?
  • How does your district identify potential principals?
  • How effective are principal preparation programs?
  • Are these preparation programs aligned to the needs of the district?

Published April 2012. Copyright Center for Public Education.
This study was written and researched by Jim Hull, Center for Public Education's Senior Policy Analyst.

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