This session will present the detailed process that has been utilized to establish the content validity for assessments to measures students’ statistical understanding in grades 6-12. These assessments have been developed in line of the Common Core State Standards in Mathematics as well as the Guidelines for Assessment and Instruction in Statistics Education. This federally funded project has utilized an Evidence Centered Approach (ECD) to develop the assessments. An overview of all five layers of the ECD process will be fully described in order to exemplify how content validity was established for the XXXX assessments.