Severe Discrepancy Model
You can file this under “the knowledge base I wish I didn’t have to have.” But here we are. Understanding the Severe Discrepancy Model is one of those things that parents are actually often told. A school psychologist will often explain this during your child’s evaluation meeting. However, I find that many parents are overwhelmed during that time, so they don’t really absorb the information.
And that’s understandable. This isn’t anything I learned in high school or college.
Yeah, but, do I really need to know this?
For most of you, no. If you agree with your school’s evaluations of your child or their categorization of your child, then no. I wouldn’t burden my brain with this.
However, if you do not agree with your child’s evaluations, you do need to do a deeper dive. Find out what assessments they used, and if they used Discrepancy Model and so on. Mind you, I am not a school psychologist. This is meant to just be a high overview.
I would say about once a month, a parent pops into our IEP Facebook group with a question about this. What typically happens is that yes, it was explained to them at a meeting recently, but now that they are digesting all the information, they need more information and explanation.
If you have a basic understanding of Discrepancy Model vs. RTI, and what your school uses, it will help you be a better advocate for your child. This will make more sense once you have a basic understanding of it.
Discrepancy Model vs. RTI
There are two primary methods of diagnosing a child with a learning disability: the severe discrepancy model, and the response to intervention (RTI) model.
Here is what IDEA says about Severe Discrepancy and RTI:
Sec. 300.307 Specific learning disabilities
300.307 Specific learning disabilities.
- (a) General. A State must adopt, consistent with §300.309, criteria for determining whether a child has a specific learning disability as defined in §300.8(c)(10). In addition, the criteria adopted by the State—
- (1) Must not require the use of a severe discrepancy between intellectual ability and achievement for determining whether a child has a specific learning disability, as defined in §300.8(c)(10);
- (2) Must permit the use of a process based on the child’s response to scientific, research-based intervention; and
- (3) May permit the use of other alternative research-based procedures for determining whether a child has a specific learning disability, as defined in §300.8(c)(10).
Within IDEA, there are eight types of specific learning disabilities (SLD), in the following areas: oral expression, listening comprehension, written expression (sometimes referred to as “dysgraphia”), basic reading skills, reading comprehension, reading fluency skills (a general term for a reading disorder is “dyslexia”), mathematics calculation, and mathematics problem solving (a general term for a math disorder is “dyscalculia”). Students can have learning disabilities in more than one area. And, as I often say, “these disabilities rarely travel alone!”
Severe Discrepancy Model
When a student is evaluated for Special Education, it is done by a professional at school (usually the school psychologist) and at other times children are tested by a professional outside of school (IEE). Most evaluators conduct either psycho-educational assessments or neuropsychological assessments. The evaluator first tests a child’s general abilities or intelligence (sometimes called “IQ testing”). These evaluations compare the child’s performance to others his or her same age. Next, the child’s academic skills are tested.
When there is a large gap between the child’s ability scores and academic skills, the child might be diagnosed with a learning disorder, if this discrepancy is not better explained by other factors. Examples of other factors would include being a non-native English speaker and being homeschooled or unschooled, and therefore not in step with their age/grade peers. The gap between the two types of scores is referred to as a “severe discrepancy.”
If your child was evaluated, and was found to have a gap, but not a severe gap, then you need to dig even deeper. Or maybe not. Let me explain. When you disagree with evaluations, you can ask for an IEE. However, most assessments should not be done twice within the same calendar year. And, you want to know, specifically, where your child did not meet the qualifying criteria. So ask what criteria your state and district uses, and where your child’s scores are relative to that.
Typically, once a student is classified as eligible for an IEP with an SLD, they are able to access special education services. Their instruction in the identified area should be supported by research-based programs that promote meaningful progress.
Response to Intervention (RTI) Model
The RTI model considers how children are responding to interventions that have been put in place (should be research-based programs). Students who are identified as being at risk for learning difficulties (they are struggling within the general curriculum) are provided with supplemental or specialized instruction called RTI. Their progress is continuously monitored, and adjustments are made as needed.
When a student fails to respond positively to the intervention, they may be diagnosed with a learning disability. Using this model, students are provided with evidence-based interventions before they are technically classified as having a learning disability. It is the failure to make progress with extra support and high-quality instruction that ultimately classifies them as learning disabled.
That sentence in italics is key here. Mind you, I hate when a child is struggling and schools pull the old “wait and see.” 99.9% of the time, a parent’s instincts are correct and the child needs help. I loathe when a team offers RTI in lieu of an IEP evaluation. They should be offered RTI and evaluations. Both, not either/or.
However, as parents, we’re all at different parts in the journey. You may just not have the bandwidth to fight this right now, and are willing to try RTI. Just please please please put a deadline on it. And keep data!
Hopefully this makes sense. If you need more clarification, these articles may help.
Here is the two printable I promised! It’s published for PA but has great information.