- Highly-rated principals are found to be particularly adept at retaining the best teachers in their schools while moving out the lowest performers, details a study from researchers at Vanderbilt University and published in the American Educational Research Journal.
- The highest performing principals rely on one performance measure above all others when identifying low-performing teachers: observation scores.
- Lower turnover is seen among teachers with higher observation scores, as well as higher student growth scores on tests, also known as value-added scores.
Numerous studies have shown that in schools with effective principals, teacher turnover is lower. While teacher retention in general is better for student outcomes, what has been largely missing in previous research is whether those teachers who are sticking around are high or low performing. This latest study, based on data from Tennessee, parsed that out, and found that teachers who receive the lowest classroom observation scores leave at substantially higher rates under an effective principal — regardless of whether they have high or low value-added scores.
This surprised the researchers, since principals everywhere are held accountable for student test score growth, and that's something that had been increasingly linked with teacher evaluations in recent years. New thinking about evaluations in Massachusetts, driven by federal policy giving more freedom to states and districts, encourages school leaders to use their own judgment. That system downplays student test scores.
In Tennessee, as in many other states, value-added scores are not processed and sent to principals until the fall of each year, which means that information comes too late for principals to use it in making staffing decisions for upcoming school years. Even the most effective principals can't make use of student test score growth information to remove ineffective teachers if they don't have access to it in time.
Taking that into account, it makes sense that principals would place a high degree of emphasis on observation scores when making decisions about which teachers to retain. The researchers theorize that principals collect observation data themselves throughout the school year. Effective principals likely use informal methods, such as “counseling out,” to remove low-performing teachers, rather than relying on administrative procedures. Such teachers typically leave the field entirely, rather than switch schools. The findings reinforce the need to ensure principals have support in their role as instructional leaders and adequate time to observe classrooms.