RTI and SLD Classification
The RTI model appears to be an appropriate first step in the SLD identification process. At the end of the RTI process, a student is known to possess significant reading difficulties that have not responded positively to validated interventions. This appears to be the only proper conclusion because nonresponsiveness should not be viewed as a diagnostic criterion. Nonresponsiveness is an outcome that may or may not be caused by SLD. Thus, the RTI model cannot stand alone as the primary means to identify SLD. Even though multi-faceted, the RTI model still represents a single criterion (i.e., nonresponsiveness) and a single criterion cannot capture the complex multivariate nature of SLD. The primary problem with discrepancy models was that they also represented only a single criterion. The advantage of discrepancy over RTI is that it documented the presence or absence of underachievement which is integral to the SLD concept. On the other hand, RTI can only document low achievement in reading. By meeting the discrepancy criterion, two things are known about a student: (a) they fall within an average IQ range (by definition, a necessary component of the SLD construct), and (b) the presence of low achievement was unexpected. If the identified underachievement is properly viewed as a necessary but not sufficient criterion for SLD classification, then the diagnostic process could proceed to validate other stipulated criteria in an effort to gain confidence about the final SLD designation (Kavale & Forness, 1995).
Kavale and Forness (2000) offered such a scheme where components from the Federal regulations were combined into an operational definition that attempted to capture the complex and multivariate nature of SLD. The components included:
- a severe discrepancy between ability and achievement,
- learning difficulties in language, reading, writing, or mathematics that require special education,
- psychological processing deficits that are associated with academic learning problems, and
- exclusionary criteria indicating factors that make the learning failure not unexpected.
A five-level hierarchical model defined the identification process as follows:
- underachievement defined by an ability-achievement discrepancy;
- significant deficits in basic skill areas (i.e., reading, writing, language, or math);
- deficits in learning efficiency based on assessments of strategy use and learning rate;
- psychological process deficits that include (but are not limited to) linguistic processing, attention, memory, perception, metacognition, and social cognition; and
- exclusion of students whose learning failure is not unexpected because it is primarily the result of MR, ED, sensory impairment, or inadequate instruction.
A schematic representation of the operational definition is shown in Figure 1.
Figure 1: Example of an Operational Definition of Learning Disability
Each level represents a necessary but not sufficient condition and SLD identification is achieved only when all five criteria are met.
Flanagan, Ortiz, Alfonso, and Mascolo (2002) deemed the Kavale and Forness (2000) operational definition "an important new direction for current practice" (p. 346), but indicated that the model "did not directly incorporate a well-validated theoretical paradigm and there was no specific guidance given on what methods might be used to accomplish effective measurement of LD" (p. 346). To extend the Kavale and Forness model, Flanagan et al. used the Cattell-Horn-Carroll (CHC) theory of cognitive abilities as the framework for understanding the nature of both cognitive and academic abilities. An operational definition of SLD was proposed that incorporates what is termed CHC Cross-Battery assessment (Flanagan & Ortiz, 2001), a guide to the selection and interpretation of both intelligence and achievement tests. The operational definition of SLD proceeds through the components shown in Table 1.
Table 1: Comprehensive Framework for LD Determination
| Level | Component | Outcome |
| I-A | Inter-Individual Academic Ability Analysis | Document specific academic skill or knowledge deficits |
| I-B | Evaluation of Exclusionary Factors | Identify alternative explanation for learning difficulties |
| II-A | Inter-Individual Cognitive Ability Analysis | Document specific cognitive deficits |
| II-B | Re-Evaluation of Exclusionary Factors | Identify alternative explanation for cognitive difficulties |
| III | Integrated Ability Analysis - Evaluation of Underachievement | Document that identified academic deficits are empirically or logically related to cognitive deficits |
| IV | Evaluation of Interference with Functioning | Document the degree to which identified deficits interfere with functioning |
| Related Considerations | Identify other limitations in areas of social skills, motor abilities, vision and hearing abilities | |
| Eligibility Recommendation | Determine eligibility for SLD classification |
After learning difficulties are documented through informal methods (e.g., classroom observation, work samples) and prereferral activities have not been successful, a comprehensive assessment is initiated based on CHC theory. For example, Level I-A would include assessments of the academic skills shown in Figure 2.
Figure 2: Level I-A: Measurement of Specific Academic Skills and Acquired Knowledge--Inter-Academic Ability Analysis
The next step is to assess each academic skill. For example, Basic Reading would be assessed by the CHC abilities shown in Table 2.
Table 2: Comprehensive Framework for LD Determination
| Corresponding CHC Ability | Definition |
| Reading Decoding (RD) | Ability to recognize and decode words or pseudowords in reading |
| Verbal (printed) Language Comprehension (V) | General development, or the understanding of words, sentences, and paragraphs in native language, as measured by reading vocabulary and reading comprehension tests. |
| Reading Speed (RS) | Time required to silently read a passage or series of sentences as quickly as possible. |
| Phonetic Coding: Analysis (PC:A) | Ability to segment larger units of speech sounds into smaller units of speech sounds. |
| Phonetic Coding: Synthesis (PC:S) | Ability to blend smaller unitsof speech together into larger units of speech. |
The final step is to choose specific tests. For example, assessments of Reading Speed (RS) may be chosen from among the following: Gray Oral Reading Tests (GORT-4), Test of Word Reading Efficiency (TOWRE), or Woodcock-Johnson Test of Achievement (WJIII). In place of the hierarchical approach of the Kavale and Forness model, the Flanagan et al. model uses a more recursive and iterative process because "information generated and evaluated at one level may inform decisions made at other levels and that a return to prior levels could well be warranted depending on the unique circumstances of the case" (p. 348).
The two models demonstrate the possibility of using a theoretically and psychometrically defensible approach to SLD identification. It is thus possible to integrate accepted concepts about SLD with theories about cognitive and academic functioning to create a comprehensive and systematic framework for making a definitive diagnosis of SLD. These operational definitions provide an inherently practical method for SLD identification that carries the potential for increased agreement about the validity of SLD classification.
Ultimately, development of an expert system model that applies findings from research to provide a diagnostic process will bring about more confident identification of students with SLD. Such a process with its in-depth evaluation of academic and cognitive skills offers the advantage of not only determining eligibility, but also identifying factors that impede student progress. by identifying targets for remediation or accommodation, the possibilities for truly individualized intervention are increased significantly. Even if a student never enters the special education system, the general education teacher, the student's parents, and the student would receive valuable information regarding why there was such a struggle in acquiring academic content to the point of possibly needing special education.
What can be said about a student who does not respond-to-instruction? Given the structure of the RTI model, it seems that the only legitimate conclusion is that the student possesses significant reading difficulties. What cannot be concluded is that the student now fits the parameters of SLD. What is the basis for the SLD designation? In reality, there is none unless there is some legerdemain where all RD magically transforms itself into SLD. The real problem with the RTI model lies not in the procedures themselves but rather in the leap of faith necessary for non-responsiveness to become SLD. The history of SLD shows that the original concept evolved from much more than a reading problem that resists treatment (Hallahan & Mercer, 2002).
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