The legal source of schools' use of response to intervention (RTI) is a matter of federal and state special education laws, although its implementation is largely a matter of general education practice. The only mention of RTI is in the Individuals With Disabilities Education Act (IDEA), and it is limited to identification of students with specific learning disability (SLD). More specifically, IDEA delegates to each state the choice of approach for identifying children with SLD: (a) permitting or requiring RTI; (b) permitting or prohibiting evaluation based on a severe discrepancy between ability and achievement; and (c) omitting, permitting, or requiring a third alternative of other research-based procedures. The purpose of this study was to systematically synthesize the scope and standards for RTI in state laws and SEA guidelines, thus providing a more in-depth view of states' specific legal requirements and normative recommendations for implementing RTI as part of the SLD identification process. (Contains 6 tables.)