Low incidence evaluations are team evaluations. Unlike a standard SLD or OHI referral where the diagnostician typically leads solo, low incidence disabilities — ID, AU, DD, MD, VI, and D/HH — require coordinated involvement from multiple specialists. Identifying the team early prevents delays, missed domains, and compliance gaps. Loop in your specialists before you plan your battery.
At-a-glance team reference
Who is typically on the team by eligibility
ID
Diag · Psych · SLP · OT (if adaptive concerns)
AU
Diag · Psych · SLP · OT · sometimes PT
DD
Diag · SLP · OT · PT · sometimes Psych
MD
Diag · OT · PT · SLP · Medical input required
VI
Diag · TVI · O&M Specialist · sometimes Psych
D/HH
Diag · D/HH Specialist · SLP · sometimes Psych
Eligibility-by-eligibility routing cards
Intellectual Disability (ID)
ID
Referral indicators
- Significantly below-average academic performance across all areas
- Adaptive behavior concerns — self-care, communication, social skills, daily living
- Prior cognitive testing suggesting significant deficits
- Global delays noted by teachers and family across multiple domains
Team members to contact
Diagnostician (lead)
School Psych
SLP
OT (if adaptive concerns)
Key sequencing notes
- Two-prong standard: requires both cognitive (≤2 SD below mean with SEM) and adaptive behavior deficits
- Adaptive behavior scale (ABAS-3 or Vineland-3) is required — not optional
- Use nonverbal cognitive instrument if language background is a validity concern
- SLP involvement especially important if communication deficits are significant
Resource: Low Incidence Reference · Adaptive Behavior Reference
Autism (AU)
AU
Referral indicators
- Social communication differences — difficulty with reciprocal conversation, pragmatics
- Restricted, repetitive behaviors or highly focused interests
- Sensory sensitivities (over or under-responsive)
- Uneven skill profile — strong in some areas, significant deficits in others
Team members to contact
Diagnostician
School Psych (lead for ADOS-2)
SLP
OT (sensory)
PT (if motor concerns)
Key sequencing notes
- ADOS-2 or MIGDAS-2 administration typically requires school psych or trained specialist
- SLP must assess social communication — pragmatic language is a core AU domain
- OT sensory evaluation is common but not always required for eligibility
- AU and ID can co-occur — adaptive behavior data is essential
- If student is non-verbal, see nonverbal instrument guidance in Low Incidence Reference
Resource: AU Evaluation Reference · Adaptive Behavior Reference
Developmental Delay (DD)
DD
Referral indicators
- Child ages 3–9 with delays across one or more developmental domains
- ECI exit or transition to ECSE — existing ECI data often available
- Delays in motor, communication, adaptive, cognitive, or social-emotional domains
- Parent or teacher reports of significant developmental differences vs. same-age peers
Team members to contact
Diagnostician
SLP
OT
PT
Psych (complex profiles)
Key sequencing notes
- Age-9 sunset: DD eligibility expires at age 9 — re-evaluation must determine a more specific eligibility category before then
- ECI records are existing data — gather before testing to avoid duplication
- Convergence of existing data (medical, ECI, developmental history) may be the primary evidence base for young children
- Play-based evaluation appropriate for youngest children — coordinate with EC team
- DD can mask AU, ID, or SLI — keep differential in mind at planning stage
⚠ Age-9 sunset: Plan the re-evaluation timeline carefully. The ARD must determine a specific eligibility before the student's 9th birthday. Do not let this sneak up on the team.
Resource: Early Childhood Guide · Low Incidence Reference
Multiple Disabilities (MD)
MD
Referral indicators
- Student has two or more concurrent disability conditions creating complex educational needs
- Existing medical diagnoses alongside cognitive or developmental concerns
- Prior eligibility in multiple categories, or significant needs across multiple domains
- Physical and cognitive needs that cannot be addressed by a single eligibility alone
Team members to contact
Diagnostician
OT
PT
SLP
Medical input
Psych (as needed)
Key sequencing notes
- Medical documentation of diagnosed conditions is typically required
- MD requires that the combination of disabilities creates educational needs that cannot be served under a single eligibility
- Nonverbal cognitive instruments are almost always necessary
- Adaptive behavior data (ABAS-3 or Vineland-3) is essential
- OT and PT involvement is the norm, not the exception
Resource: Low Incidence Reference · Adaptive Behavior Reference
Visual Impairment (VI)
VI
Referral indicators
- Documented vision loss or diagnosed visual condition (acuity, field loss, cortical VI)
- Failed vision screening with referral to ophthalmologist or optometrist
- Student squinting, holding materials unusually close, or reporting visual difficulty
- Medical diagnosis of progressive or degenerative eye condition
Team members to contact
Diagnostician
Teacher of the Visually Impaired (TVI)
O&M Specialist
Psych (as needed)
Key sequencing notes
- TVI must be involved — VI eligibility and functional vision assessment require a Teacher of the Visually Impaired
- Medical documentation of visual acuity (best corrected) is required
- Orientation & Mobility assessment determines independent travel needs
- Standard cognitive and achievement instruments may require tactile or auditory modifications — coordinate with TVI before testing
- Cortical Visual Impairment (CVI) requires specialized functional vision assessment
⚠ Do not begin cognitive testing without TVI input on appropriate instrument modifications. Standard visual administration may yield invalid results.
Resource: Low Incidence Reference
Deaf / Hard of Hearing (D/HH)
D/HH
Referral indicators
- Failed audiological screening or documented hearing loss
- Audiologist report indicating hearing loss in speech frequencies
- Student frequently asking for repetition, misunderstanding verbal directions
- Speech or language delays attributed to hearing loss
Team members to contact
Diagnostician
D/HH Specialist
SLP
Psych (as needed)
Key sequencing notes
- Audiological evaluation is required — current audiogram must be on file before eligibility determination
- D/HH Specialist involvement is required for functional hearing assessment and communication mode determination
- SLP evaluates communication, speech, and language impact of hearing loss
- Cognitive instruments with reduced auditory demands should be prioritized
- If student uses ASL or another signed language, language dominance considerations apply — bilingual evaluator may be needed
- Hearing aids or cochlear implant status should be documented and accounted for in test conditions
⚠ Confirm current audiogram is on file before scheduling any testing. Hearing status can change — a dated audiogram may not reflect current functioning.
Resource: Low Incidence Reference
General reminders for all low incidence evaluations
Consent & notice
All evaluators conducting assessment must be listed in the evaluation consent and notice. If specialists are added after initial consent, issue an amended notice before they begin testing.
Related services at ARD
Specialist involvement in the evaluation often signals related services needs at ARD. Loop in your ARD facilitator early so service providers can be included in the ARD meeting.
EB + low incidence
A student can be both EB and low incidence. If language background is also a factor, coordinate EB routing decisions (see EB Eligibility Screener) with low incidence team planning.
Timelines
Specialist availability can affect your 45-school-day timeline. Identify team members and confirm availability as soon as consent is received — don't wait until you're ready to test.