Discrepancy Model vs. RTI: What Parents Actually Need to Know.

If you’re hearing terms like discrepancy model or RTI in an IEP meeting, it can feel like a lot. Big, clunky, unfamiliar words and acronyms. That’s ok, grab a cup of tea, and dig in–I have a knack for explaining IEP things in a way that parents understand.

Here’s the bottom line: Both are ways schools decide whether a child has a specific learning disability (SLD) and qualifies for special education services. You don’t need to become an expert. But if you’re questioning your child’s evaluation or eligibility decision, understanding the basics helps you ask better questions.

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. 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.

What is the Discrepancy Model?

The discrepancy model looks at the gap between two things:

• Your child’s cognitive ability (IQ or “potential”)
• Your child’s academic performance (reading, writing, math)

If there is a significant gap between those two, the school may identify a learning disability.

Example: A student has average intelligence but is reading several grade levels behind. That gap is called a “severe discrepancy.”

How it determines eligibility

• The school gives standardized tests (IQ + academic testing)
• They compare the scores
• If the gap meets your state’s criteria, the child may qualify for an IEP under SLD

Important things parents should know

• Schools are not required to use this model anymore, but some still do
• It relies heavily on testing (which doesn’t always tell the full story)
• Kids sometimes have to “fail enough” before the gap is large enough

How to tell if your school is using the Discrepancy Model

Look for these signs:

• You see IQ scores vs. achievement scores in the evaluation
• The team talks about a “gap” or “discrepancy”
• You hear phrases like:
  • “He doesn’t qualify because the gap isn’t large enough”
  • “Her cognitive ability is consistent with her achievement”
• There is less discussion about interventions tried over time

If that’s happening, they’re likely using (or heavily relying on) a discrepancy approach.

What is RTI (Response to Intervention)?

RTI is a different approach. Instead of focusing on a test score gap, it looks at this:

How does your child respond when we give them targeted support?

RTI is part of what’s often called a multi-tiered system of support (MTSS).

What RTI looks like in practice

1. All students are screened to find who may be struggling
2. Students get extra support (interventions)
3. The school tracks progress over time
4. Decisions are made based on that data

If a child does not make enough progress, even with strong interventions, they may be identified as having a learning disability.

How it determines eligibility

• The school provides research-based interventions
• They collect data over time
• If the child does not respond adequately, that lack of progress can support SLD eligibility

This means: It’s not about a single test, it’s about patterns over time.

Important things parents should know

• RTI is meant to provide help earlier, not make kids wait
• Schools should use evidence-based interventions, not random worksheets
• Progress monitoring data should be shared with you regularly
• RTI should NOT delay or replace an evaluation (You can request an evaluation at any time)

How to tell if your school is using RTI

Look for these signs:

• You hear terms like:
  • “Tier 1, Tier 2, Tier 3”
  • “Interventions”
  • “Progress monitoring”
• Your child is receiving:
  • Small group instruction
  • Targeted reading/math support
• You are shown data charts or progress graphs
• The team says things like:
  • “We need to see how they respond to intervention”
  • “They’re not making adequate progress”

How These Affect IEP Eligibility

Both models are trying to answer the same question: Does your child have a disability that impacts learning enough to need special education?

They just answer it differently:

• Discrepancy Model: “Is there a big enough gap between ability and performance?”
• RTI Model: “Did the child fail to make progress even with strong support?”

Under IDEA:

• Schools cannot be required to use discrepancy
• They must allow RTI or other research-based methods

However…..IDEA does say that if you formally request IEP evaluations, in writing– that if they are going to decline to evaluate your child, they must provide you that information on a PWN.

One thing I always tell parents

This isn’t either/or. Your child can:

• Receive RTI supports and
• Be evaluated for an IEP at the same time

If a school tells you to “wait and see” with RTI before evaluating, that’s something to push back on.

When you should dig deeper

You’ll want to ask more questions if:

• Your child was denied eligibility
• The explanation feels vague or confusing
• You’re hearing “they don’t qualify” but your child is clearly struggling
• You’re not being shown actual data

Ask:

• What model are you using?
• What criteria does our state require?
• Where did my child fall short?

10 Steps for Parents (After Learning About Discrepancy vs. RTI)

Once you understand how your school is making decisions, the next step is making sure your child isn’t getting lost in the process.

Here’s what I would do, in a practical, step-by-step way.

1. Ask one simple question first

Start here: “What method did you use to determine eligibility: discrepancy, RTI, or both?” If they can’t explain it simply, that’s a red flag.

2. Ask to see the actual data

Don’t rely on summaries or opinions. Ask for:

• Evaluation reports (IQ + achievement scores, if done)
• RTI/intervention data (progress monitoring graphs)
• Notes on what interventions were used

You’re looking for:

• Patterns of your child’s performance
• Not just “teacher says” or “team feels”

3. Compare what they did to what your child actually needs

This is where parents often get stuck. Ask yourself:

• Are the supports matching the problem?
• Is the instruction targeted and specific?
• Is there measurable progress?

If your child is:

• Still struggling
• Not making progress
• Getting generic support

That’s not enough.

4. If your child is in RTI, put boundaries on it

RTI should not drag on forever. You can say: “How long are we going to try this before we make a decision?”

And get specifics:

• Timeline (weeks, not “we’ll see”)
• What counts as progress
• What happens if progress doesn’t happen

Also: Start keeping your own notes at home. Dates matter. My parent IEP toolkit has specific tools for parents to do this quickly and easily.

5. Request an evaluation (if you haven’t already)

You do not have to wait for RTI. You can send a written request: “I am requesting a full evaluation for special education eligibility.”

That starts the legal timeline. If they push back with “let’s try RTI first,” you can say: “We can do both.” Because you can.

6. If they say your child doesn’t qualify, dig into why

Don’t stop at “they didn’t qualify for an IEP.”

Ask:

• Which criteria were not met?
• What scores or data points were used?
• How close were they?

Sometimes kids miss eligibility by a small margin, but still clearly need support. That’s when you decide whether to:

• Accept it and monitor
• Or push further

7. Consider an Independent Educational Evaluation (IEE)

If you disagree with the school’s evaluation: You can request an IEE at public expense. You don’t have to prove they were “wrong” just that you disagree.

This is especially helpful if:

• The testing felt incomplete
• The results don’t match what you see at home
• The explanation didn’t make sense

8. Make sure support is happening now, not later

Regardless of eligibility: Your child still needs help.

Ask:

• What support is in place right now?
• How often?
• Who is delivering it?

If the answer is vague, push for specifics.

9. Keep everything in writing

This matters more than most parents realize. After meetings, follow up with:

• A quick summary email
• What was agreed on
• Any timelines discussed

Paper trails protect you.

10. Trust what you’re seeing day to day

If your child is struggling, that matters. Even if:

• Scores are “average”
• “his grades are fine“
• The gap isn’t “big enough”
• The school says “let’s wait”

You’re allowed to say: “This isn’t working, and we need to do something different.”

You don’t need to master the models. You need to:

• Understand how your school made the decision
• Look at the actual data
• Speak up when it doesn’t match your child

Because eligibility decisions shouldn’t be about fitting into a system. They should be about getting your child what they need.