IEP Glossary · Specially Designed Instruction

Specially Designed Instruction: The Core of What an IEP Should Provide

Specially designed instruction (SDI) is the legal term for what makes special education different from regular education. It is not extra help, a quieter room, or preferential seating. It is instruction that is adapted in content, methodology, or delivery to meet your child’s unique disability-related needs. If your child’s IEP doesn’t describe actual SDI, they may be receiving accommodations but not special education.

Meghan Moore, BCBA, M.A. Special Education

Founder, Mama Moore Advocacy · Updated April 1, 2026

The Three Ways SDI Adapts Instruction

IDEA defines specially designed instruction as adapting, as appropriate to the needs of the child, the content, methodology, or delivery of instruction. Each of those three dimensions means something specific.

Content: What is taught is different. The level, scope, or sequence of the curriculum is modified to match the child’s learning profile. For a student with a significant intellectual disability, this might mean learning functional life skills rather than grade-level academic content. For a student with a specific learning disability, it might mean a modified scope and sequence within reading.
Methodology: How it is taught is different. Evidence-based instructional approaches specific to the disability are used, structured literacy for dyslexia, behavior-analytic teaching for students with autism, explicit instruction for students with executive function deficits. The school should be able to name the methodology, not just describe the setting.
Delivery: How the instruction reaches the child is different. One-on-one instead of group instruction. Multisensory materials. Shorter task chunks with frequent breaks. Visual supports integrated into direct instruction.

What SDI Must Look Like in the IEP

SDI is not implicit. It needs to be written into the IEP in enough detail that a substitute teacher could pick it up and know what to do. That means:

Named instructional approaches, not just service categories. “Wilson Reading” or “direct instruction in phoneme segmentation”, not “reading support.”
Frequency: how many minutes per day or week the SDI is delivered
Setting: individual, small group, or within the general education classroom
A clear connection to the specific present-level deficits and the goals that address them
Delivery by a certified special education teacher, not an aide without qualified supervision

What SDI Is Not

If the IEP lists “resource room, 45 minutes per day” and nothing else, that is a location, not SDI. A room is not an intervention. The IEP should describe what happens in that room.

The following are accommodations. They may be appropriate and necessary, but they are not SDI:

Preferential seating
Extended time on tests
Reduced homework load
Having a paraprofessional present in the classroom
Oral reading of tests
Use of text-to-speech tools

A student receiving only these supports is receiving a 504 plan, not an IEP in the full sense. If they have an IEP with no SDI described, the document may be technically compliant in form but not in substance.

Why SDI Matters for Your Child’s IEP

FAPE requires SDI, not just accommodations. If your child needs different instruction and is only receiving access modifications, the IEP may not be providing the free appropriate public education that IDEA requires.

The absence of SDI is one of the most common substantive deficiencies advocates find when reviewing IEPs. It often shows up in IEPs where children have been receiving “support” for years without making meaningful progress, because what they have been receiving is accommodation, not instruction. Accommodation gives a child access to the same curriculum. SDI changes the instruction to meet the child where they are.

The legal standard is whether the SDI is reasonably calculated to enable the child to make progress in the general education curriculum. That standard cannot be met by accommodation alone when the child’s disability requires different instruction to make progress.

Is Your Child’s IEP Providing Real SDI?

Meghan reviews IEPs for parents who want to know whether what’s on paper reflects what special education is supposed to provide.

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What is specially designed instruction (SDI)?

Under IDEA, specially designed instruction means adapting the content, methodology, or delivery of instruction to address the unique needs of an eligible child that result from their disability. SDI is not extra help. A general education teacher staying after class to re-explain a concept is not SDI. A reading specialist using Orton-Gillingham techniques with a student who has dyslexia is. A classroom aide sitting next to a student to keep them on task is not SDI. A special education teacher using discrete trial training to build a foundational academic skill is. The distinction matters because IDEA requires SDI as the core of what special education delivers. When an IEP lists services without describing the instructional approach, methodology, or how the content is being adapted, parents cannot verify that SDI is actually happening. The IEP must be specific enough to show what is being taught differently and why, not just where or how often a child receives services.

What is the difference between SDI and accommodations?

Accommodations change how a student accesses instruction or demonstrates knowledge, extended time, preferential seating, text-to-speech, reduced assignments. They do not change the curriculum or how it is taught. SDI changes the instruction itself, the content, the method, or how it is delivered. A child who needs different instruction needs SDI. A child who can access standard instruction with modifications may need only accommodations.

How can I tell if my child is receiving SDI or just accommodations?

Look at the IEP and ask these questions: Is there a description of what the instruction looks like, not just where or when it happens? Does the SDI connect directly to the goals and the present levels? Does it describe an actual instructional approach, not just a service location? If the IEP just says “reading support in resource room” without describing what kind of reading instruction is being provided, that is likely not SDI.