This study examines how middle school teachers’ networks influence their mathematical knowledge for teaching (MKT) and instructional practices. We also examined how mathematics coaches’ expertise, in the form of MKT, plays a role in augmenting the extent to which teachers learn through interacting with close colleagues. Drawing on longitudinal data from a larger NSF-funded project that has worked with 29 middle schools in four large, urban districts, we used multilevel linear models with cross-level interaction effects and in-depth sensitivity analyses of the effects of close colleagues and coaches. Our results show that changes in teachers’ instructional practice were positively related to their access to instructional expertise through interactions with close colleagues. But we did not find a similar significantly positive association between changes in teachers’ MKT and access to their close colleagues’ MKT expertise. Rather, coaches’ MKT expertise positively moderated the extent to which teachers learned MKT from their close colleagues through seeking advice on teaching mathematics; that is, having an expert coach in the school enhanced the MKT learning opportunities that teachers had from interacting with close colleagues. Results from this study shed light on how to support teachers’ on-the-job learning and successfully implement ambitious instructional reforms in schools.

This article examines how the effects of institutions on teaching practices can be mediated by social networks within schools. The study focuses on teachers’ responses to policies developed from the National Reading Panel’s recommendations for teaching reading.

This article examines the mathematics course-taking of White, African American, and Latino students in racially diverse schools and the effects of different opportunity structures in those schools on college preparation and college-going using data from the Adolescent Health and Academic Achievement Study (AHAA) and the National Longitudinal Study of Adolescent Health (Add Health).

This article explores how social network analysis can help researchers studying teachers' professional interactions understand the internal structure of teacher communities and assess teachers' social capital for implementing ambitious reforms. Case study data from two schools in California illustrate how network data complement interview data to help explain the success or failure of reforms to take hold in schools.

This commentary proposes a set of guidelines for school governance in the form of a constitution, inspired by national constitutions that have proven valuable for navigating competing interests through representation and checks and balances.