Association for Public Policy Analysis & Management

Background: Prior research suggests that when teachers experience favorable working conditions, such as collaboration with colleagues, supports from school leaders, and opportunities for professional growth, teacher and student outcomes improve. Teachers can create favorable working conditions for other teachers if they are effective in their own classrooms and can provide instructional leadership. Prior research suggests that National Board Certified Teachers (NBCTs) are an example of teachers who combine these characteristics. Therefore, NBCTs are well-positioned to facilitate favorable working conditions for all teachers, which could translate to positive student and teacher outcomes—a hypothesis that we test in the current study. We conducted the study in North Carolina and Kentucky, where substantial resources are invested to support NBC and teachers who become certified.

Purpose: We examine the relationship between the concentration of NBCTs at a school and teacher and student outcomes. Concentration, because the literature on collective behavior and some studies in education suggest that for NBCTs to be better positioned to have an impact, their number at a school needs to reach a certain critical mass. We operationalized concentration as the proportion of NBCTs in teaching roles relative to other teachers. The study addresses two research questions: (1) What is the relationship between the concentration of NBCTs and student achievement in reading and mathematics? (2) What is the relationship between the concentration of NBCTs and teacher retention? We examine student achievement in grades 4-8 and teacher retention in grades K-8. We examine whether the relationship varies by school characteristics, such as the proportion of economically disadvantaged students.

Findings: We find a positive relationship between the concentration of NBCTs and student achievement in math and reading in North Carolina. Our estimates and effect sizes are, however, small (less than 0.01 standard deviation) and we find no statistically significant relationships in KY. The analysis based on school characteristics suggests that compared with disadvantaged schools, advantaged schools benefit from an increase in the concentration of NBCTs to a greater extent on math achievement. The effect sizes are also small. The analysis of teacher retention suggests no statistically significant relationship between the concentration of NBCTs and teacher retention in both states. However, the results show that with an increase in the concentration of NBCTs teacher retention improves at schools serving a high proportion of economically disadvantaged students compared to schools serving a low proportion of economically disadvantaged students, but only in North Carolina. The estimate for this relationship is the strongest in our study. It represents the spillover effect: that is, the retention rate is for non-NBCTs.

Significance: The main contribution of the study is that it lends preliminary support to the idea that NBCTs can be a conduit to better teacher retention at schools that serve a high proportion of economically disadvantaged students. This finding is significant, because schools that serve a high proportion of economically disadvantaged students often struggle to retain teachers, which can lead to negative teacher and student outcomes.