RTI and SLD Identification in Pennsylvania: Why Use RTI to Identify SLD?

In the previous three blog entries, I described how the Pennsylvania Department of Education (PDE) had taken the position that school districts need to demonstrate that they had built an effective infrastructure of instruction and intervention prior to being approved to use response to intervention (RTI) as part of a comprehensive evaluation for specific learning disabilities (SLD). I described Pennsylvania's training program for implementing RTI in the first blog post in this series, and specifics of the infrastructure for what Pennsylvania calls Response to Instruction and Intervention (RTII) in the second post. In the third entry, I described the application to use RTI for SLD identification, detailing nine areas of assessment, instruction, and intervention that school districts need to demonstrate for their application to be approved.

In this post, I want to take a step back and articulate why using RTI as part of comprehensive evaluation for SLD is a good idea. To start, it is useful to recount the concerns that were articulated in the early 2000s about the traditional way of identifying students with SLD, namely the ability–achievement discrepancy approach. Three problems with that approach are particularly salient.

First, many scholars and researchers have described the “wait to fail” phenomenon associated with the ability–achievement discrepancy approach. Very young children in the primary grades who display significant difficulties in learning to read cannot be identified as eligible for special education because the extent of their deficiencies cannot be adequately quantified using norm-referenced tests. A typical scenario is that a struggling 1st grade student has to wait until 3rd grade (and conceivably continue to fail) to be identified as having an SLD. Of course, few would advocate that significant numbers of young children need to be identified as having SLD, particularly in view of the extensive research that now exists that demonstrates that early intervening with robust intervention protocols can result in extensive improvements in basic skills when implemented systematically in the early grades. To a large extent, it is the mindset that is associated with RTI, along with the RTI infrastructure of frequent assessment, effective core instruction, and targeted interventions that can put an end to “wait to fail.”

The second concern is that the tests typically used in the ability–achievement discrepancy approach, while capable of discriminating among students, do not lead to useful interventions. This issue is a contentious one in the field of school psychology and to some degree in special education. Although few support the ability–achievement discrepancy approach, a number of theorists propose that the results of tests of cognitive processing can lead to specific and unique interventions that are effective in producing gains in academic achievement. This approach is well documented in the area of phonological awareness. Tests of phonological awareness are useful in identifying students with difficulties in this critical skill, which is a fundamental component of learning to read. More important, research has demonstrated that interventions to improve students’ phonological skills lead to improved outcomes in reading. However, at this point, other tests of cognitive processing have not been demonstrated to lead to interventions that, when implemented, produce meaningful gains in functional academic skills. The documented association of some of these cognitive processes with reading skills does not signal the availability of useful interventions. Further research indicating that interventions based on these assessments lead to actual student gains is needed before this approach to assessment can be seen as useful. In contrast, measurement procedures associated with RTI have been derived from direct methods of assessing functional academic skills (e.g., curriculum-based assessment, curriculum-based measurement, curriculum-based evaluation). The premise of using RTI for eligibility decision making is that the same assessment instruments that have been used to guide instruction can also serve as important evidence for the identification of SLD.

The final concern relates to which students are identified as having SLD under various evaluation models. It is well known that the ability–achievement discrepancy approach systematically eliminates students with below average IQs from consideration for SLD identification. Basically, under the ability–achievement discrepancy approach, students with IQs between 70 and 85 exist in a “no man's land” in which they are ineligible for special education regardless of the extent of their academic deficiency. These so-called “slow learners” are imagined to learn at a parallel but slower rate than typical students. Many teachers over the years have found it to be a bit absurd that these students, who often display significant difficulties in learning to read in the classroom, are not identified, while students with higher IQs are found to have SLD. Research over the past two decades has indicated that there is no relationship between IQ and learning to read (when the IQ is above the level of intellectual disability). Consequently, the usefulness of the ability–achievement discrepancy in identifying which students are most in need of special education services is tenuous. In contrast, a comprehensive evaluation using RTI instead of the ability–achievement discrepancy identifies as having SLD those students who were significantly deficient in basic skills in comparison to peers, and more important, who do not make adequate progress even when provided with robust, scientifically based interventions.

The use of RTI as both an instructional improvement initiative and as a fundamental component of a comprehensive evaluation for identifying students with SLD should substantially address these concerns. Diligent implementation of the instruction and intervention infrastructure should produce high percentages of students who achieve proficiency in basic skills, particularly in the early grades. The few students who do not make such gains are good candidates for further evaluation. When this evaluation consists of functional assessments of academic skills and careful progress monitoring of their RTI, increases in diagnostic accuracy in terms of which students are most deservedly identified as having SLD should be realized.
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