Inside: A discrepancy model may be used to determine IEP eligibility. Some states still use the RTI model. Learn what the difference is and how it applies to your child.

You can file this under “the knowledge base I wish I didn’t have to have.” But here we are. Understanding the difference between the Discrepancy Model vs RTI for IEP eligibility is something that happens at the beginning of the IEP process. And it’s really not beginner content.

A school psychologist will often refer to this during your child’s evaluation or eligibility meeting.

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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.

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Learning IEPs is not fun, but necessary.

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.

What is the Discrepancy Model?

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 online 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.

The discrepancy model is an approach used in special education to determine whether a student has a specific learning disability (SLD). This model compares a student’s cognitive ability or IQ to their academic achievement in specific areas such as reading, writing, or math.

The discrepancy model assumes that if a student has a significant difference between their expected achievement based on their cognitive ability and their actual academic achievement, then they may have a specific learning disability.

For example, if an 8th grade student has an IQ of 100 but is only performing at a third-grade level in reading, there is a significant discrepancy between their cognitive ability and academic achievement. This is sometimes referred to as IQ achievement discrepancy or IQ discrepancy model.

Under the discrepancy model, if a student is identified as having an SLD, they may be eligible for special education services, including an Individualized Education Program (IEP) that outlines their specific needs, goals, and services.

However, there has been criticism of the discrepancy model in recent years, as some argue that it may not accurately identify students with learning disabilities and may disproportionately affect certain groups of students, such as those from low-income or minority backgrounds.

As a result, alternative models such as Response to Intervention (RTI) have been developed to identify and support students with learning difficulties.

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 IEP 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.

SLD is one IEP eligibility category and may use severe discrepancy model vs rti
Click here to read more about the SLD IEP category.

What is the RTI Model?

RTI stands for Response to Intervention, which is an approach used in education to provide early and targeted support to students who are struggling with academic or behavioral challenges.

The RTI model is a multi-tiered system of support (MTSS) that involves the following components:

  1. Universal screening: All students are screened regularly to identify those who may be at risk for academic or behavioral difficulties.
  2. Tiered interventions: Students who are identified as at-risk are provided with increasingly intensive and targeted interventions, based on their specific needs. These interventions may include additional instructional support, small-group instruction, or individualized interventions.
  3. Progress monitoring: Students’ progress is regularly monitored to determine if the interventions are effective and if additional support is needed.
  4. Data-based decision making: The interventions are adjusted based on the data gathered through progress monitoring, with the goal of ensuring that students are making adequate progress.

The RTI model is designed to provide early and proactive support to students, with the goal of preventing more serious academic or behavioral difficulties from developing. The model is flexible and can be adapted to meet the needs of individual students and schools.

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The RTI model has been widely adopted in schools as an alternative to the discrepancy model for identifying and supporting students with learning difficulties. However, some critics have raised concerns about the effectiveness of the model and the potential for over-identification of students as at-risk.

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 put a deadline on it. And keep data!

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.

Both the discrepancy model and Response to Intervention (RTI) are approaches used in education to identify and support students with learning difficulties. Here are some of the pros and cons of each approach:

Discrepancy Model


  • The discrepancy model has a clear and objective criteria for identifying students with specific learning disabilities, which can make it easier to identify those in need of support.
  • It can provide a useful framework for determining the nature and severity of a student’s learning difficulties, which can inform the development of an effective intervention plan.
  • The model is consistent with the requirements of the Individuals with Disabilities Education Act (IDEA), which mandates that a student’s disability must adversely affect their educational performance in order for them to be eligible for special education services.


  • The discrepancy model can be rigid and inflexible, and may not accurately identify students who have learning difficulties that do not fit neatly into the model’s criteria.
  • The model relies heavily on standardized testing, which may not accurately capture a student’s abilities or needs.
  • The model may not be culturally sensitive or equitable, and may disproportionately identify students from certain racial or ethnic groups as having learning disabilities.

Response to Intervention (RTI)


  • RTI is a proactive and preventative approach that provides early and targeted interventions to students who are at risk of academic or behavioral difficulties.
  • The model is flexible and can be adapted to meet the needs of individual students and schools, which allows for a more personalized and responsive approach to intervention.
  • RTI focuses on the use of data to inform decision making, which can help to ensure that interventions are effective and appropriately targeted.


  • The RTI model can be resource-intensive, requiring significant time and resources to implement effectively.
  • The model relies heavily on data, which can be a challenge for schools that lack the resources or expertise to collect and analyze data effectively.
  • There is some concern that the RTI model may be over-identifying students as at-risk or in need of special education services.

Overall, both the discrepancy model and RTI have their strengths and weaknesses, and the choice of approach may depend on the specific needs and resources of the school and student population.

It is important for schools and educators to carefully consider the benefits and limitations of each approach and to choose the one that is most likely to effectively support students’ academic and behavioral needs.

Discrepancy Model for SLD Eligibility

Here is what IDEA says about Severe Discrepancy and SLD:

Sec. 300.307 Specific learning disabilities, Statute/Regs Main » Regulations » Part B » Subpart D » Section 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).

Under the Individuals with Disabilities Education Act (IDEA), there are eight specific categories of specific learning disabilities (SLD) that may qualify a student for special education services. These categories include:

  1. Reading fluency: A learning disability that affects a student’s ability to read accurately, quickly, and with proper expression.
  2. Reading comprehension: A learning disability that affects a student’s ability to understand what they read, including understanding vocabulary, sentence structure, and text organization.
  3. Math calculation: A learning disability that affects a student’s ability to solve basic math problems, including addition, subtraction, multiplication, and division.
  4. Math reasoning: A learning disability that affects a student’s ability to understand and apply math concepts, including problem-solving, critical thinking, and abstract reasoning.
  5. Written expression: A learning disability that affects a student’s ability to communicate effectively through written language, including spelling, grammar, and organization.
  6. Listening comprehension: A learning disability that affects a student’s ability to understand and process spoken language, including following directions and retaining information.
  7. Oral expression: A learning disability that affects a student’s ability to communicate effectively through spoken language, including pronunciation, grammar, and organization.
  8. Basic reading skills: A learning disability that affects a student’s ability to understand basic reading skills, including letter recognition, phonemic awareness, and decoding.

It’s important to note that these categories are not mutually exclusive, and a student may have difficulties in multiple areas. Additionally, the identification of a specific learning disability requires a formal evaluation by a qualified professional, such as a school psychologist, and the development of an Individualized Education Program (IEP) to address the student’s specific needs.

Students can have learning disabilities in more than one area. And, as I often say, “these disabilities rarely travel alone!”

Hopefully this makes sense. If you need more clarification, these articles may help.

SLD Discrepancy Model

Here is the two printable I promised! It’s published for PA but has great information.

Free IEP Binder
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