Early intervention means getting support for your child as young as possible — before age 3 — when the brain is developing fastest and responds most to therapy. For children with autism or signs of developmental delay, starting services early leads to better outcomes in communication, social skills, and daily living than starting later.

This guide explains what early intervention is, who qualifies, what it looks like in practice, and how families in California can access it at no cost.

What Early Intervention Means

Early intervention refers to specialized services for children from birth through age 2 who have a developmental delay or a condition — like autism — that affects their development. The National Institute of Child Health and Human Development (NICHD) describes early intervention as services that "can greatly improve a child's development" by helping children learn to communicate, connect, and build foundational skills during the period when the brain is most flexible. (Source: NICHD, nichd.nih.gov.)

The word "early" matters more than most families realize. Research consistently shows that younger children make greater gains from therapy than older children starting the same program. A 2020 review found that 12 out of 14 studies examining age at therapy start reported that younger children had better outcomes — with age explaining between 3% and 13% of the variation in treatment results. (Source: "Is Earlier Better?" PMC7421097, 2020.)

Who Qualifies for Early Intervention

Under the Individuals with Disabilities Education Act (IDEA) Part C, every state must provide free early intervention services to children from birth through age 2 who have a developmental delay or a diagnosed condition. You don't need to prove a large delay. A confirmed diagnosis of autism is enough to qualify.

Eligibility covers five developmental areas: communication, physical development, cognitive development, social-emotional development, and adaptive development (self-care skills like eating and dressing).

One important point that surprises many families: you don't need a diagnosis to request an evaluation. If you have a concern, you can refer your child yourself — and the evaluation is free.

Despite this, only 15% of preschool-age children later diagnosed with autism received early intervention services before age 2, according to a 2025 study in Autism Research. And only 50.3% of 8-year-olds with autism in the most recent CDC data were even evaluated for developmental concerns by age 36 months. (Sources: Lidstone et al., Autism Research, 2025; CDC ADDM Network, MMWR, April 2025.)

What Early Intervention Looks Like

Early intervention is not one single therapy — it's a package of services tailored to your child. The specific mix depends on your child's needs, identified through an evaluation. Common services include:

ABA therapy (Applied Behavior Analysis). ABA is the most extensively researched therapy for young children with autism. It teaches communication, play, and daily living skills through structured practice with positive reinforcement. For very young children, ABA is typically delivered in a naturalistic, play-based way rather than at a desk. Research from 2025 found that intensive ABA programs produce IQ gains of 9 to 15 points in young children with autism. (Source: Cureus, PMC12514992, September 2025.)

Early Start Denver Model (ESDM). ESDM blends ABA strategies with a developmental, relationship-based approach. It's designed specifically for toddlers ages 12 to 48 months and is delivered through play, daily routines, and caregiver coaching. A landmark clinical trial published in Pediatrics found that children who received ESDM for two years gained 17.6 standard score points in IQ, compared to 7.0 points in children receiving community treatment. (Source: Dawson et al., Pediatrics, 2010.)

Speech-language therapy. A speech therapist works on how your child communicates — including words, gestures, facial expressions, and alternative communication tools if needed. For toddlers with autism, early speech therapy often focuses on back-and-forth communication and building the foundation for language.

Occupational therapy. An occupational therapist helps with fine motor skills, sensory processing, and self-care skills like eating, dressing, and tolerating different textures. These challenges are common in young children with autism and can affect daily family life significantly.

Parent-mediated therapy. Some of the most promising recent research involves training parents to deliver therapy strategies during everyday routines — bath time, meals, play. A 2024 meta-analysis of 144 studies including 9,038 children found that low-intensity parent-led ESDM (3 hours per week of coaching) produced clinically meaningful improvement — comparable to higher-intensity clinic-based programs. (Source: JAMA Pediatrics, PubMed 38913359, 2024.)

All of these services are coordinated through a written plan called an Individualized Family Service Plan (IFSP). Unlike a school-based IEP, an IFSP is family-centered — it includes goals for the whole family, not just the child, and recognizes parents as the most important people in their child's development.

What the Research Shows

The evidence base for early intervention in autism is among the strongest in pediatric medicine.

Children who receive early intervention make meaningful gains in language, social skills, and cognitive development compared to children who don't. And the earlier services begin, the better the outcomes tend to be. A 2023 study found that even a one-year difference in start age — beginning at age 3 versus age 4 — produced a measurable difference in symptom reduction and language development. (Source: PMC9857540, 2023.)

The most dramatic demonstration of early intervention's impact came from a clinical trial published in JAMA Pediatrics, which started a social communication program with infants showing early signs of autism between 9 and 12 months. At age 3, only 6.7% of children in the intervention group had an autism diagnosis, compared to 20.5% of children who received standard community care. (Source: JAMA Pediatrics, 2022.)

The takeaway isn't that early intervention eliminates autism — it's that the brain's flexibility in the first three years of life creates a window that families and clinicians can use together.

How to Access Early Intervention in California

In California, early intervention services are delivered through the Early Start program, administered by the Department of Developmental Services (DDS). California has 21 regional centers statewide that coordinate and fund Early Start services.

Here's how to get started:

Step 1: Make a referral. Anyone can refer a child — you don't need a doctor's note. Call the Early Start Baby Line at 1-800-515-2229 or email earlystart@dds.ca.gov. Your child's pediatrician can also make the referral.

Step 2: Receive an evaluation. The regional center has 45 days from referral to complete the evaluation and begin services if your child qualifies. The evaluation is free and covers all five developmental areas.

Step 3: Develop an IFSP. If your child qualifies, your regional center service coordinator works with your family to develop an IFSP — a written plan listing your child's goals and the services your family will receive. Services begin immediately.

Step 4: Services begin. Services are delivered in your home, a childcare setting, or another natural environment where your child spends time. All Early Start services are provided at no cost to families.

California has the earliest median age of autism diagnosis in the country — 36 months, compared to a national median of 47 months — partly because of the Early Start infrastructure. (Source: CDC ADDM Network, MMWR, April 2025.)

What Happens When Your Child Turns 3

Early intervention services under IDEA Part C end when your child turns 3. At that point, if your child still needs support, they transition to Part B of IDEA — the school-based special education system.

The regional center is required to notify your local school district at least 90 days before your child's third birthday. A transition meeting must happen to plan the handoff. If your child qualifies for school-based services, an IEP must be in place and services must begin by their third birthday — not after.

If your child does not qualify for school-based special education, the transition plan must still include a path to other community services.

For families who have been receiving ABA therapy through a regional center, it's worth knowing that ABA through private insurance does not end at age 3. Intercare works with children and families well beyond the early intervention period, through school age and adolescence.

For more on what to do after an autism diagnosis, including how to find a provider and navigate insurance, see our post-diagnosis guide.

Frequently Asked Questions

What age does early intervention cover?

Early intervention under IDEA Part C covers children from birth through age 2 — up to their third birthday. Services delivered through California's Early Start program fall within this window. After age 3, children who need continued support transition to school-based services under IDEA Part B.

Do I need a diagnosis to access early intervention?

No. Under federal law, a parent concern is enough to request a free evaluation. If the evaluation finds that your child has a developmental delay or a qualifying condition, they are eligible for services — even without a formal autism diagnosis. Getting evaluated early is always worth doing.

Is early intervention free?

Yes. Under IDEA Part C, early intervention evaluations and services are provided at no cost to families. In California, these services are coordinated through your regional center.

What is an IFSP?

An IFSP (Individualized Family Service Plan) is the written plan that describes your child's goals and the services your family will receive. It's reviewed every six months and updated to reflect your child's progress. Unlike a school IEP, it's designed to be family-centered — it includes supports for caregivers, not just the child.

How is early intervention different from ABA therapy?

Early intervention is a broad category of services that can include ABA therapy, speech therapy, occupational therapy, and other supports. ABA therapy is one type of early intervention — and one of the most researched. Many children in early intervention receive ABA as part of their IFSP alongside other services.

What if my child is already 3 or older?

ABA therapy and other supports are still available for children over 3. School-based services (through your local school district) can begin at age 3 with an IEP. Private ABA therapy through insurance is also available for older children and is not limited by IDEA's age cutoff. Contact Intercare to learn about services for your child's age and needs.