Teacher turnover has proven to be not only costly for schools, but also detrimental to teacher effectiveness and student learning. Still, some teacher attrition is not always a bad thing, in particular when the teachers who leave are the least effective.

Better understanding the reasons why teachers leave has become an important subject of research.

Tuan Nguyen, Lam Pham, Matthew Springer, and Michael Crouch recently took a comprehensive look at the last four decades of research literature on attrition and retention. Like any meta-analysis, this study is not simply old wine in a new bottle, for it leverages the strength of 120 studies to quantify what matters, and how much, for teacher retention.

Some of the factors that rise to the top in the meta-analysis are teachers' personal characteristics such as age and marital status, or their qualifications, such as years of experience or type of certification. Few of these attributes are things a district can do much about, but there were some findings with policy implications

1. One of the more novel findings is that teacher evaluations are not a deterrent to the profession, but rather an instrument of teacher retention. The study sums up the results of newer research that shows that both the existence of evaluation systems and teachers' higher scores in that system are associated with lower attrition. In other words: evaluating teachers improves retention for the most effective teachers.


2. While a school district cannot change a teacher's age or years of experience, they should be able to target those teachers with policies to improve retention, such as professional development, induction, mentoring, and overall administrative support. This study summarizes that more and better (according to teachers) professional development, teachers' participation in induction and mentoring, a better work environment, and better administrative support all relate to significantly lower teacher attrition.


3. A non-novel but still underutilized concept is that on which many studies agree: Teachers who are paid better tend to leave less. Studies also coincide in that the mere participation of a teacher in a merit pay system can decrease the probability of attrition by 24%!