This paper examines how policy pressure for increased performance on standardised measures of student achievement influenced the teacher learning practices that arose in a school setting in Queensland, Australia. Drawing upon research and theorising of governing by numbers, and applications to the governance of education, and particularly teachers' learning, the research analyses how a group of Year 3 teachers collaborated to better inform themselves about the nature of their students' learning. The research reveals that the governance of teachers' learning under current policy conditions was manifest through both teachers' compliance with and critique of a strong focus upon school, regional, state and national data--specifically, students' attainment in "leveled" readers and other school-based standardised measures of reading and mathematics, and school, state and regional results on national literacy and numeracy tests. There is little research that highlights the tensions around these numbers as governing technologies in relation to specific formal, ongoing instances of teacher professional development practices. The research cautions against the influence of such governing processes for how they potentially narrow teachers' attention to more standardized measures of students' learning, even as teachers may critique these more reductive effects.