Identifying Learning Disabilities: RTI vs PSW vs Discrepancy Models-and Why Families Sometimes Need Advocacy or a Private Evaluation:
Why Identification Models Matter
When parents suspect their child has a learning disability, the evaluation process can feel confusing and inconsistent. One reason: schools use different models to determine eligibility for special education services. The model a school uses is determined by the school district.
The method a district uses—Response to Intervention (RTI), Patterns of Strengths and Weaknesses (PSW), or the Discrepancy Model—can directly influence whether a child qualifies for an IEP, even when academic struggles are clear.
Understanding these models helps families know what to expect, how to interpret results, and when to seek advocacy or a private evaluation for additional clarity.
1. Response to Intervention (RTI)
RTI focuses on how a student responds to tiered (increasingly intensive), evidence-based interventions before being identified as having a learning disability.
Tier 1: Universal classroom instruction.
Tier 2: Small group interventions for students who need more support.
Tier 3: Intensive, individualized interventions.
If a student doesn’t make adequate progress despite multiple interventions (over time), the school may initiate an evaluation for a Specific Learning Disability (SLD).
Pros:
Emphasizes early intervention rather than waiting for failure.
Tracks ongoing progress with data.
Cons:
Can delay formal evaluations if schools overextend intervention periods.
Quality of interventions and data tracking varies by school.
Impact on Families:
Parents may see their child struggle for months (or years) while the school “collects data,” delaying access to specialized instruction. Advocacy is often needed to ensure the school moves forward with an evaluation in a timely way.
2. Patterns of Strengths and Weaknesses (PSW)
The PSW model looks for cognitive and academic patterns that show specific areas of strength and weakness consistent with a learning disability profile.
For example, a student may have average reasoning skills but weak phonological processing and reading fluency—suggesting dyslexia/SLD-Reading.
Pros:
Provides a more detailed, nuanced picture of how a student learns.
Recognizes that learning disabilities often coexist with strong skills in other areas.
Cons:
Requires careful interpretation of testing data.
Not all districts use this model consistently or have staff trained to analyze results accurately.
Impact on Families:
PSW can be empowering when used correctly—it validates a child’s potential while pinpointing challenges. However, when misapplied, schools may conclude the pattern is “too inconsistent” to qualify, leaving parents frustrated and confused. Different school districts also use different cut-off scores to determine whether a score is considered a strength or a weakness, leading to more confusion and frustration.
Private evaluations often use this same model but apply it more comprehensively, helping clarify borderline cases or overlooked learning differences.
3. The Discrepancy Model
The Discrepancy Model is the traditional approach, comparing a student’s IQ (ability) and achievement (performance) scores. A significant gap—or discrepancy—between the two can indicate a learning disability. Historically this model was accepted by many schools and psychologists, but is currently considered outdated.
Pros:
Straightforward and easy to understand conceptually.
Cons:
Waits for students to fail before qualifying for help (“wait to fail” model).
Doesn’t consider how interventions or instruction impact performance.
Impact on Families:
Students who are bright but struggling may fall through the cracks—scoring too high for eligibility yet too low to succeed independently. This is a common reason families seek private evaluations for more thorough and diagnostic insight.
Why Families Often Need Advocacy or Private Evaluations
Each model has benefits and limitations, but the outcome can vary dramatically depending on the district, evaluator, and interpretation of data.
Parents may need an educational advocate or private evaluator when:
The school denies an evaluation due to “insufficient data.”
The evaluation concludes “no disability found,” or “does not qualify” despite ongoing struggles.
The report lacks detail or doesn’t clearly explain what’s driving the difficulties.
Recommendations are too vague to guide meaningful intervention.
Private evaluations offer independent, comprehensive insight—often identifying subtle processing or learning differences that school models overlook. The information gained through a private evaluation can and must be considered by a school-team regardless of the model they use. Advocacy ensures those findings are understood and considered within IEP or 504 meetings, bridging the gap between data and action.
Final Thoughts
The model used to identify a learning disability can determine whether your child receives specialized support—or not. Understanding RTI, PSW, and the Discrepancy Model empowers parents to ask better questions, recognize red flags, and seek the right help when needed.
If your child isn’t making progress, yet you’re being told they don’t qualify for services, it may be time to bring in an advocate or private evaluator who can ensure data is interpreted accurately and your child’s needs are truly met.
