Does Mentoring Reduce Turnover and Improve Skills of New Employees? Evidence from Teachers in New York City

Mentoring has become an extremely popular policy for improving the retention and performance of new teachers, but we know little about its effects on teacher and student outcomes. I study the impact of mentoring in New York City, which adopted a nationally recognized mentoring program in 2004. I use detailed program data to examine the relationship between teacher and student outcomes and measures of mentoring quality, such as hours of mentoring received and the characteristics of mentors. Although assignment of teachers to mentors was non-random, I use instrumental variables and school fixed effects to address potential sources of bias. I find strong relationships between measures of mentoring quality and teachers' claims regarding the impact of mentors on their success in the classroom, but weaker evidence of effects on teacher absences, retention, and student achievement. The most consistent finding is that retention within a particular school is higher when a mentor has previous experience working in that school, suggesting that an important part of mentoring may be the provision of school specific knowledge. I also find evidence that student achievement in both reading and math were higher among teachers that received more hours of mentoring, supporting the notion that time spent working with a mentor does improve teaching skills.