Teachers have access to more data than ever before, but comparative research on how often and why teachers use different types of data is scarce. The Nebraska Department of Education identifies summative (state-level), interim (benchmark-level), and formative (classroom-level) assessment data as key measures of student learning. The department values professional learning to support teachers in using these data to adjust instruction in order to help students meet state content standards, and it needs research to inform a state-level professional learning plan. In March 2019 the department administered the Teacher Data Use Survey and received responses from 3,572 teachers and 171 principals across 353 schools. The survey measured teachers' use of summative, interim, and formative data to inform instruction; their perceived competence in using data; their attitudes toward data; and their perceptions of organizational supports for using data. The study also examined whether data use varied by teacher characteristic such as highest degree earned and years of experience in education. [For the full report, see ED610179; for the appendixes, see ED610181; for the study brief, see ED610183.]