The Teacher-Student Data Link (TSDL) Project brings several states and school districts together to determine a common approach to one of the most critical components of their educational data systems —the link between student outcomes and teacher influence. Across the nation, states are looking to use accountability data to increase student learning. Leveraging the collective experiences, knowledge, and resources of the participating states, the TSDL project is developing a common, best practice framework for a teacher of record definition, as well as business processes for collecting and validating linked teacher and student data. The Center for Educational Leadership and Technology (CELT) is conducting the project, with funding from the Bill & Melinda Gates Foundation and guidance and dissemination support from the Data Quality Campaign (DQC).