Response to intervention (RTI) arose, in part, from the limited success of the pre-referral process, an approach advocated in the 1980s and 1990s, and accurately measuring the discrepancy between aptitude and achievement in young children. Reflecting these concerns, when the Individuals with Disabilities Education Act (IDEA) was reauthorized in 2004, it added language allowing RTI to be used as a component of evaluation for special education eligibility. Educators are encouraged to use scientific, research-based interventions as part of the process to determine eligibility for special education. Students who succeed in response to the additional intervention continue to receive instruction to meet their needs, while those who continue to struggle and do not show higher achievement are referred for a comprehensive evaluation. Project Forum at the National Association of State Directors of Special Education (NASDSE) worked with two other OSEP-funded centers, the IDEA Partnership and the National Center on Response to Intervention (NCRTI), to select six states for review of their response to intervention frameworks. The review examined documentation provided on the states' websites regarding their implementation of RTI. This document describes information found on state websites and subsequently provided by state staff in the areas of RTI structure, administration, implementation, data and outcomes and challenges. Website information where state-specific information was found is appended. (Contains 3 footnotes.)