Abstract
This interpretative case study of one public elementary school in the state of Washington examined teachers' reasoning about exercising their autonomy. Results of the study indicated that participants exercised autonomy to alter mandated curricular and assessment policies. Teachers diagnosed students' academic and emotional needs, and then changed curricular policies stipulated by the state and district to improve student achievement. As teachers' diagnoses were discretionary, participants' utilised professional expertise, prior teacher education, and practitioner inquiry to support their exercise of power. Recommendations for providing teachers with learning opportunities to develop their professional judgments are discussed.