The drive for improvement in the international context of high-stakes accountability and performativity has strengthened the push for data-based decision making in schools and school systems. However, the push to use data has focused on that which is predominantly quantifiable and standardized. Rather than extending the knowledge and skills of the profession, narrow definitions and mandated decision-making using standardized data can lead to unintended consequences, including prescription and a lack of equity as individual contexts are overlooked. Drawing on a three-year ARC Linkage project, this paper examines how teachers and school leaders engaged with a broad range of data through collaborative inquiry designed to improve equity and the performance of all students. We use examples from two secondary schools to show different ways that teachers worked together and used a broad range of data to make decisions about their practice. Building on these examples, we argue that the effective interpretation of specific types data as part of collaborative inquiry can interrupt current practices and promote equitable changes in schools.