What is the difference between a discrepancy model and an RTI-based approach for identifying a Specific Learning Disability, and why is multi-method data important?

• A. The discrepancy model relies on a gap between ability and achievement; the RTI-based approach uses response to instruction data; multi-method data reduces misclassification due to measurement error, language differences, or instruction quality.
• B. They are identical.
• C. The discrepancy model is used for behavioral issues only.
• D. RTI replaces discrepancy analysis.

Answer: (A)

The main idea is how SLD identification differs between using an IQ-achievement gap and using response to instruction data, and why triangulating information matters. The discrepancy model looks for a gap between what a student can do (cognitive ability) and what they achieve academically, often requiring a noticeable difference before eligibility is considered. An RTI-based approach, instead, relies on ongoing progress monitoring and data on how the student responds to evidence-based instruction across levels of support, rather than waiting for a large gap to appear. This approach emphasizes learning rate and responsiveness within a multi-tier framework.

Using multiple kinds of data is essential because it protects against mislabeling due to measurement error, language differences, or the quality of instruction. A single test or measure can be influenced by language proficiency, testing conditions, or classroom context. By pulling together diverse sources—progress-monitoring data, standardized assessments, work samples, and teacher observations—you get a more accurate picture of the student’s learning needs and can distinguish true learning difficulties from other factors.