Using participant data to extend the evidence base for intensive behavioral intervention for children with autism.

The team pooled raw scores from 453 children across 16 separate studies.

All kids had autism and received intensive ABA for at least two years.

They asked: how many show a real jump in IQ and daily-living skills?

Roughly 3 in 10 children gained a reliable IQ boost.

Only 1 in 20 children in low-intensity or eclectic care did the same.

About 1 in 5 also gained real-world skills like dressing or talking in phrases.

Han et al. (2025) updated this work with nine newer trials and found the same small-to-medium gains, so the picture still holds 15 years later.

Reed et al. (2007) showed 30 hours a week is the sweet spot; more hours added no extra benefit, matching the dose Sigmund’s team flagged.

Slater et al. (2020) added a twist: the 25-hour advantage only shows up for kids with mild autism symptoms, so severity now guides dosing.

Linstead et al. (2017) cranked the idea further: both high weekly hours AND more total months pack the biggest punch across every skill area.

Use the 30-hour rule as your opening request to funders, but screen symptom severity first. If the child shows severe autism, start at 15–20 hours and build up while you train parents. Track progress each month; if gains stall, raise intensity or extend duration before the window closes.