For Parents

For Parents

Research Round-Up

This week we summarize the Project AIM meta-analysis of intervention effects on language in children with autism.

Many interventions have been developed to help children with autism learn language and communication skills, but it is challenging to understand which interventions and strategies may work best for each child. This meta-analysis reviewed 60 articles about autism interventions for children 8 years old and younger to determine their effectiveness on a variety of language outcomes. Listed below is a summary of their findings as well as implications for clinicians and researchers.


  • The average percentage of male participants in the reviewed studies was 82.7%
  • The average chronological age of participants was 47.5 months, with an average language age of 20.19 months


  • They found small-to-moderate effects on receptive language, expressive language, and combined language outcomes. However, expressive language outcomes were significantly higher than receptive language outcomes.
  • There were no differences in effect sizes by type of intervention (e.g., behavioral interventions, NDBIs, developmental interventions, etc.).
  • The intensity of intervention (e.g., number of hours) did not impact the effect sizes.
  • Interventions delivered by a clinician, or a clinician and a caregiver, had larger effects than those delivered by caregivers or educators alone.
  • The chronological age of participants did not impact the effects of intervention.
  • There were no differences in intervention effects based on participants’ autism symptomatology (e.g., those with more vs fewer autism characteristics).
  • Intervention effects were larger for participants with a higher language age
  • Effect sizes were not significantly different for proximal vs. distal outcomes (e.g., discrete skills vs. broader, generalized skills).

Implications/future directions:

  • Future studies should include more female participants to determine the effectiveness of interventions for young girls with autism.
  • Improving receptive language may be an important focus of future research, as these outcomes were less-studied and had smaller intervention effects than expressive language outcomes.
  • Although there were no differences in language outcomes by intervention type, it may still be important to individualize the type of intervention to fit each family’s specific needs.
  • Because more hours may not necessarily lead to better outcomes, it may be important to focus on the specific characteristics of the interventions used for a family rather than the number of hours of therapy a child gets each week. Fewer high-quality hours may be as effective, if not more effective, than more low-quality hours.
  • Clinicians trained specifically in language and communication (e.g., speech-language pathologists) may be best suited to guide interventions with language as a primary goal. Caregiver and educator-implemented interventions may potentially have effects on other social communication outcomes, though this is out of the scope of this meta-analysis.
  • Because participants with higher initial language had larger gains than those with low initial language skills, further research may be necessary to find ways to optimize interventions for those with lower language skills.
  • There were no significant differences in effects for discrete, proximal skills (e.g., the skills specifically taught in an intervention) versus broader, generalized skills. However, more longitudinal data may be important to determine how generalized language learning was over time.