It's indisputable that great teachers lead to successful students, as the presidential candidates have touted, but what about students' connection to their school principals?
A study published in Education Next has found that the effect of highly effective principals on student achievement is equivalent to 2-7 months of additional learning each school year, while ineffective principals negatively impact student achievement by a comparable amount.
For their study, the authors used a value-added model similar to the one used to measure teacher quality, but applied the calculation to the entire school. They examined the extent to which math achievement in a given school is higher or lower than would be expected based on student characteristics, including their achievement the previous year. The authors attributed achievement differences in schools enrolling similar students to the quality of the principal.
The analysis relied on administrative data compiled as part of the University of Texas at Dallas Texas Schools Project, which in conjunction with the Texas Education Agency has combined different data sources to create matched data sets of students, teachers and principals over many school years. Included in the data are all Texas public school teachers, administrators, staff and students in each year.
The authors focused on the years 1995-2001, which included 7,420 individual elementary and middle school principals. Due to the fact tenure could potentially affect a principal’s impact, the first analysis concentrated only on data from the first three years a principal led a school, and determined that a principal at the 75th percentile of their effectiveness measure contributes to average achievement gains relative to the average principal, while one at the 25th percentile lowers achievement.
These gaps are more prominent in high-poverty schools, where the difference between the 25th and 75th percentile principal is larger, as the impact of a principal who is statistically more effective than average can translate to seven additional months of learning in a single academic year.
The researchers also determined that the relationship between higher teacher turnover and lower average “value added” in a given grade is stronger as principal quality increases. This is consistent with the theory that managing teacher quality is an important way for principals to influence school quality.
The study also found that Texas schools serving a high proportion of low-income students are more likely to have first-year principals and less likely to have leaders who have been at the school at least six years. The least effective principals are also least likely to remain in their current position and more likely to leave the public school system entirely.
That said, the majority of low quality principals tend to simply switch schools as opposed to being forced out of the public education sector. The authors suggest this is where superintendents come into play, as an effective superintendent is one who makes good decisions when it comes to the retention and assignment of principals.