Schools implement Response to Intervention (Rtl) for two major purposes. The first is to provide a coordinated system of high-quality instruction and intervention for all students in the school (Burns & Vanderheyden, 2006; Haager, Klinger, & Vaughn, 2007; National Association of State Directors of Special Education, 2006). This system can be envisioned as a framework of effective instruction to prevent academic problems from occurring and effective interventions to address problems that do occur in a timely and appropriate manner. The system is integrated and coordinated to support all students to reach primary learning objectives (Fuchs, Fuchs, & Zumeta, 2008; Greenwood, Kratochwill, & Clements, 2008). The second purpose of Rtl is to diagnose specific learning disabilities (SLD) in students who do not respond adequately to instruction and intervention (O'Conner, 2007; Reynolds & Shaywitz, 2009; Torgesen, 1997, 2004). Strong empirical evidence supports the prevention and intervention purpose of Rtl (Baker et al., 2008; Gersten et al., 2009; Greenwood, Kratochwill, & Clements, 2008; Vaughn & Fuchs, 2006), but evidence for using Rtl for SLD determination is lacking (Fuchs, Mock, Morgan, & Young, 2003; Reynolds & Shaywitz, 2009).