An early intervention program provides developmental services to infants and toddlers, from birth through age 2, who have delays or disabilities. These programs are federally mandated under Part C of the Individuals with Disabilities Education Act (IDEA) and operate in every U.S. state and territory. The goal is to support a child’s development as early as possible, strengthen a family’s ability to help their child grow, and reduce the need for special education once the child reaches school age.
Who Qualifies for Early Intervention
Eligibility is based on delays or diagnosed conditions across five developmental domains: cognitive, physical, communication, social-emotional, and adaptive (self-help skills like feeding or dressing). A child doesn’t need delays in all five areas. A significant delay in even one domain, or a diagnosed condition that carries a high probability of delay, can qualify a child for services. Each state sets its own definition of what counts as a “significant” delay, so the threshold varies. Some states define it as a 25% delay below expected levels, others use 33% or 50%, and some use standard deviation scores from developmental assessments.
Common reasons children enter early intervention include premature birth, Down syndrome, cerebral palsy, hearing loss, autism spectrum concerns, and unexplained delays in talking, walking, or social engagement. You don’t need a formal diagnosis to get a referral. A parent, pediatrician, childcare provider, or anyone involved in the child’s life can refer the child.
How the Process Works
Once a child is referred, federal law requires that the evaluation, family assessment, and initial planning meeting all be completed within 45 days. That timeline is strict and applies nationwide. The evaluation itself is always free, regardless of your state or income.
During the evaluation, a team of professionals assesses the child across all five developmental domains to determine whether delays exist and how significant they are. If the child qualifies, the team works with the family to create an Individualized Family Service Plan, commonly called an IFSP. This document is the backbone of everything that follows. It outlines the specific changes the family and team want to see in the child’s development, the services that will support those goals, and when, where, and how those services will be delivered. The IFSP can also include goals for the family, such as learning strategies to support their child’s communication at home.
The IFSP is reviewed regularly and updated as the child’s needs change.
What Services Look Like
The specific services a child receives depend entirely on their individual needs. Common examples include speech therapy for children who are not babbling or forming words on schedule, physical therapy for delays in crawling or walking, and occupational therapy for difficulties with feeding or fine motor skills. Some families receive specialized instruction, family counseling, nutrition services, vision therapy, assistive technology, or nursing support.
One defining feature of early intervention is where it happens. Federal law requires that services be provided in “natural environments” to the maximum extent appropriate. In practice, this means a therapist comes to your home, your child’s daycare, or another setting where your child normally spends time. The intent is not to replicate a clinic session on your living room floor. Therapists are expected to work with parents and caregivers, coaching them on how to weave developmental support into everyday routines like mealtime, bath time, and play. A family’s typical activities, communication partners (siblings, grandparents, peers), and values all factor into the plan. Services in a clinical setting are only used when the IFSP team determines that a child’s needs genuinely cannot be met in a natural environment, and that decision must be documented with a justification.
What It Costs
Several core parts of the program are free in every state: the initial screening, the full developmental evaluation, family assessments, creation and review of the IFSP, service coordination, and transition planning. These cannot be billed to you regardless of income.
For therapeutic services like speech therapy, physical therapy, or specialized instruction, cost depends on your state. Some states provide all early intervention services at no charge. Others use a sliding fee scale based on household income, or bill your private insurance or Medicaid. Critically, no child can be denied services because a family cannot afford to pay. If you decline to give consent for the program to bill your insurance, your child still receives services.
Does Early Intervention Work
The evidence is strong. Children who participate in Part C programs show measurable improvements in social-emotional skills, learning, and behavior. Roughly two-thirds of children who receive early intervention substantially improve in these areas, and about half catch up to a level appropriate for their age. The National Early Intervention Longitudinal Study found that 42% of children who received services did not need special education by the time they reached kindergarten. Over the long term, children served through early intervention tend to have better health outcomes and less severe disabilities as adults.
The reason timing matters is that brain development is most rapid in the first three years of life. Intervening during this window takes advantage of the brain’s heightened ability to form new connections and adapt, which is why waiting to “see if they grow out of it” can mean missing the period when support is most effective.
Spotting Delays Early
The CDC tracks developmental milestones at regular intervals: 2, 4, 6, 9, 12, 15, 18, 24, and 30 months, then annually through age 5. These milestones cover how children play, learn, speak, act, and move. Missing one or more milestones at any checkpoint is a reason to talk to your child’s doctor and ask about a developmental screening, not a reason to panic, but a reason to act. The American Academy of Pediatrics recommends standardized developmental screening at 9, 18, and 30 months, with autism-specific screening at 18 and 24 months.
If your child has lost skills they previously had, that is an especially important signal to seek a referral promptly.
What Happens at Age 3
Early intervention under Part C ends on a child’s third birthday. The transition process begins well before that. At least 90 days before the child turns 3 (and up to 9 months before, if all parties agree), the early intervention team must have a transition plan in the IFSP. For children who may qualify for continued services, the program notifies the state education agency and the local school district, sharing the child’s name, date of birth, and parent contact information.
A transition conference brings together the family, the early intervention team, and the school district to discuss what comes next. If the child is suspected of having a disability that qualifies for preschool special education under IDEA Part B, the school district evaluates the child and, if eligible, develops an Individualized Education Program (IEP). Federal law requires that IEP to be in place by the child’s third birthday, so there is no gap in services.
Not every child who receives early intervention will need Part B services. For the children who have caught up to their peers, the transition is simply into a typical preschool setting, which is one of the program’s primary goals.