Understanding How Schools Identify Specific Learning Disabilities: What Parents Need to Know About PSW, RTI, and the Discrepancy Model
The Law Changed in 2004 — But Not Everyone Caught Up
If your child has been diagnosed with dyslexia, dysgraphia, or another learning disability, you may be wondering: will the school see it the same way? The answer is complicated — and it depends a lot on where you live and what method your school district uses to determine eligibility for special education.
The Individuals with Disabilities Education Act (IDEA), updated in 2004, significantly changed how schools identify students with Specific Learning Disabilities (SLD) in three important ways.
First, schools must not require a severe discrepancy between intellectual ability and academic achievement as the basis for identifying SLD. This effectively retired the old discrepancy model as a mandatory standard, though — as we'll see — it didn't disappear entirely.
Second, schools must collect data showing that the student has had access to high-quality instruction and has failed to respond to intervention. This is the Response To Intervention (RTI) requirement, and it applies universally — every SLD determination must include this data.
Third, schools may use alternative research-based procedures to further inform the eligibility determination. This is the opening that Patterns of Strengths and Weaknesses (PSW) fits into — it is not a separate required pathway, but rather a permissible additional method that districts can layer on top of the required RTI data.
So to be clear: RTI is not optional, and PSW is not an equal alternative to it. RTI data is the floor. PSW is an approach a school may choose to build on top of that foundation.
This post focuses especially on PSW — what it is, why it matters, and what it means for your child.
Why the Old Discrepancy Model Was a Problem
The traditional discrepancy model had real costs for real kids. Here's why it fell out of favor:
It required students to fail first. To show a significant gap between ability and achievement, academic scores had to drop low enough to register as a meaningful discrepancy. Families and educators often described this as a "wait to fail" approach — children weren't identified until they were already significantly behind.
It excluded students with below-average IQs. The model required a roughly average IQ (typically 85 or above) as a baseline. Students who weren't bright enough to show a dramatic discrepancy — but also weren't delayed enough to qualify for Intellectual Disability services — fell through the cracks entirely. These are children who have real learning disabilities but exist in a gap between two eligibility categories.
It wasn't particularly accurate. A discrepancy between IQ and achievement scores doesn't tell us much about why a student is struggling or what kind of support they need.
Enter RTI — And Its Limitations
After 2004, many districts moved toward RTI as their primary method for identifying SLD. The logic made sense: schools were already required to provide high-quality, tiered academic interventions, so why not use a student's response to those interventions as evidence of a disability?
RTI (and its broader cousin, MTSS — Multi-Tiered Systems of Support) works like this: students receive increasingly intensive, evidence-based instruction. If a student fails to make adequate progress despite high-quality intervention at multiple tiers, that lack of response becomes part of the eligibility determination.
One important legal note: schools cannot use the need for more intervention data as a reason to delay an evaluation when a disability is suspected. If there's reason to believe a child has a disability — and a diagnosis like dyslexia is absolutely reason to believe — the district must start the evaluation process within the required timeline. Best practice is to begin testing and collect intervention data simultaneously. When the team reconvenes to make an eligibility decision, they'll have a rich picture from both formal testing and real-world intervention response.
It's also worth noting: children who make solid progress in intervention and can access grade-level instruction in the classroom generally won't qualify for special education. IDEA requires evidence that a child needs supports that general education — including even intensive, individualized Tier 3 interventions — cannot provide.
What Is PSW — The "Third Way"?
Patterns of Strengths and Weaknesses is an approach the federal law explicitly permits. PSW uses cognitive and academic testing to identify a specific profile: some cognitive abilities are average or above, while others are below average, and those weaknesses align with below-average academic skills in a theoretically meaningful way.
Think of it this way: a student with dyslexia might show average visual-spatial reasoning and average working memory, but below-average phonological processing — and that pattern shows up alongside below-average reading scores. The pattern makes sense given what we know about how reading works in the brain.
Different PSW models exist — Concordance-Discordance, XBA (Cross-Battery Assessment), and others — and different states use different models. This means a child who qualifies under one state's PSW framework might not qualify if the family moves. Eligibility can vary not just by state, but sometimes by district or even by the individual school psychologist conducting the evaluation.
How Oregon and Washington Approach SLD
In Oregon, districts have flexibility. They may use RTI/MTSS data to determine SLD eligibility, and they may also layer PSW testing on top of that. Both approaches are recognized.
In Washington, the story is messier. The state's special education regulations haven't been updated in a long time, and for years, individual districts — and even individual school psychologists — chose their own approach. Some stuck with severe discrepancy, some used RTI, some combined RTI with PSW, and some used PSW models of their own choosing with no statewide guidance.
That is now changing. Washington has committed to moving away from the severe discrepancy model entirely. By the 2028–29 school year, Washington school districts will no longer use severe discrepancy to determine SLD eligibility. Instead, the state is moving toward an approach grounded in instructional and intervention data, RTI — a shift intended to identify students earlier, reduce inequities, and better serve students of color and multilingual learners. School districts will be allowed to do additional testing to suss out cognitive and academic strengths and weaknesses, but PSW will not be a part of the criteria for SLD eligibility.
The Controversy Around PSW
Within the field, PSW is not without its critics. Researcher Ryan McGill and others have raised important concerns:
Subtest scores are less reliable than composite scores. When we pull apart cognitive batteries to look at individual subtests or narrow ability clusters, we're working with scores that have more measurement error. Building eligibility decisions on those scores is statistically shaky.
PSW can still exclude students with lower IQs. Some state PSW models require an overall IQ at or above 85 or 90. In practice, this reinstates a version of the old discrepancy model — just dressed up in different language.
Test bias is a serious equity concern. Cognitive and achievement tests can reflect cultural and linguistic backgrounds in ways that disadvantage multilingual learners, students from lower-income families, and students of color. Using PSW with these populations risks misidentifying — or failing to identify — students based on test performance that reflects their life experience more than their neurological profile.
These aren't reasons to dismiss PSW entirely, but they are reasons to use it carefully and critically.
Clinical Diagnoses vs. School Eligibility: Not the Same Thing
One more important distinction: a clinical diagnosis of a learning disability — from a private psychologist, neuropsychologist, or other licensed clinician — is not the same as a school eligibility determination, and vice versa.
When clinicians evaluate for reading, writing, or math disorders outside of school, they follow the *Diagnostic and Statistical Manual of Mental Disorders* (DSM-5). The DSM defines Specific Learning Disorder based on academic skills that are substantially below what's expected given a person's age, schooling, and intelligence — assessed with individually administered, standardized tests. A diagnosis requires that the difficulties have persisted despite targeted intervention (that’s RTI!) and that they aren't better explained by other factors. In practice, this framework most closely resembles the traditional discrepancy model: it looks for a meaningful gap between cognitive ability and academic performance. The clinical diagnosis can be powerful and validating for families, and it can inform school planning, but it does not automatically confer eligibility for special education services. Schools make their own eligibility determinations using their state's criteria and methodology.
What Parents Can Do
Knowledge is power in this process. Here's where to start:
Ask upfront what method the district uses. At the very beginning of the evaluation process, ask the school psychologist: What methodology does this district use to identify SLD? Request that they share the district's handbook or written guidance on SLD evaluations. The answer will shape everything that follows.
Know that a diagnosis is a reason to evaluate — not to wait. If your child has been diagnosed with dyslexia, dysgraphia, or a similar learning disability by a clinician outside of school, that diagnosis is grounds to suspect a disability and request an evaluation. The school cannot tell you they need to run more rounds of intervention before they evaluate. The evaluation and the intervention data collection can — and should — happen at the same time.
Understand what "progress" means in this context. If your child is making strong gains in intervention and accessing grade-level work, they likely won't qualify for special education — even if they have a diagnosis. Special education is reserved for students whose needs cannot be met within the general education system, including its intervention tiers.
A Final Word
I've been a school psychologist for a long time. I know what teams are required to do, how long evaluations should take, and when pushing harder for an evaluation is the right call. The system is complicated, and the rules vary in ways that aren't always fair or consistent — but understanding how it works puts you in a much stronger position to advocate for your child.
The more you know, the better. I'm here to help you navigate it. Contact me HERE.