In recent years, researchers have turned their attention to the relationship between teacher social interactions and the successful implementaion of reforms. The limited research to date has tended to support this relationship, with some research finding significant correlations between teacher collaboration and student achievement. In this study, we use quantitativeÂ methods to determine the relationship between within-school networks formed around the interpertation and use of the data on the National Tests Report and student achievement, as measured by the proportion of students meeting or exceeding the proficiency standard on the National Tests. The sampple comprised 56 teachers from seven schools within an urban school district. Teachers responded to a social network survey and two dimensions on the OCI. Interviews of 15 principals and five focus groups of 31 teachres provided the qualitative data. Findings suggested that a relationship between shcools with high collegial trust exhibited deeper collaborative structures and a higher proportion of students performing at standard on the National Tests. These findings have implications for principals and techers who will need to find ways to maximize the use of within-school skill setsÂ and expertise, especially in a resource-strapped system.