The Study to Explore Early Development (SEED): a multisite epidemiologic study of autism by the Centers for Autism and Developmental Disabilities Research and Epidemiology (CADDRE) network.

SEED is a big-picture study, not a therapy trial. The Centers for Autism and Developmental Disabilities Research and Epidemiology (CADDRE) enrolled preschoolers aged 2-5 across six U.S. sites.

They collected deep data on each child: full developmental history, language samples, medical records, and DNA. The goal was to map the autism phenotype and hunt for genetic and environmental risk factors.

The paper does not report new intervention results. Instead, it lays out the study plan and shows that a large, diverse sample of preschoolers with autism, developmental delays, and typical development can be recruited and assessed with the same protocol.

Hedley et al. (2010) and Stevens et al. (2018) already give you quick screeners for toddlers—Spanish ADEC-SP and the 5-item OERA. SEED extends their work by adding a deep-dive data set you can use to check if those brief tools catch the same kids its full protocol flags.

Kim et al. (2014) created the OSEL language measure for 2-5-year-olds with autism. SEED’s language samples could validate OSEL in a much larger sample, moving the tool from pilot to ready-to-use.

Nadwodny et al. (2025) found LENA audio counts correlate modestly with clinical language tests. SEED’s own language metrics let you test whether LENA holds up across different sites and cultures, something the smaller LENA study could not do.

If you assess young children, think of SEED as a reference library. You can compare your local screening numbers to its gold-standard data, check if your favorite tool works across races and incomes, and grab free language or genetics variables for your own analysis. No new kit to buy—just a richer picture of what autism looks like at age three.