Eldevik, S., Strømgren, B., Eikeseth, S., Fields, A., Goetz, C. M., & Titlestad, K. B. (2026). Clinically significant outcomes of early intensive behavioral intervention for children with autism spectrum disorders: An individual participant data meta-analysis. Autism Research, 19(1), 1-32. https://doi.org/10.1002/aur.70169

Reviewed by:
Elizabeth Renshaw, MS, RBA (Ont.), BCBA, and Mary Jane Weiss, PhD, BCBA-D, LBA
Endicott College

Why research this topic?

Research Synopses - Psuchological, Educational and Therapeutic InterventionsEarly intensive behavioral intervention (EIBI) is an evidence-based treatment based on the principles of Applied Behavior Analysis (ABA; Klintwall & Eikeseth, 2014). The treatment is often provided to children with autism, to focus on developmentally appropriate goals surrounding skill deficits and challenging behavior (Klintwall & Eikeseth, 2014). There is an ongoing debate regarding the effectiveness of EIBI, leading to confusion among professionals and caregivers (Copeland & Buch, 2013). Inadequate understanding of the core components of EIBI has led to interventions being classified as EIBI even when they lack key essential elements, suggesting treatment drift in implementation. The article by Eldevik et al. (2026) reviews the important components of EIBI. They indicate that the following elements must be incorporated to be considered EIBI:

  • Programming across a wide variety of skill areas
  • Programming that is tailored to the individual’s needs, preferences, and abilities
  • A number of different interventions that are based on Applied Behavior Analysis (ABA) and include a variety of instructional approaches
  • Goals that are developmentally sensitive and aligned with what is appropriate for a learner’s chronological age, developmental level, and social interest
  • Supervision by a qualified professional who is able to navigate the complexity and diversity of client needs
  • Parent training that empowers caregivers with strategies that make meaningful differences in their familial contexts
  • Gradual move from one-to-one, small group, then large group instruction using a systematic and individualized approach
  • Intensive programming that ensures large numbers of learning opportunities and high levels of engagement
  • Early start (i.e., preschool-aged)
  • Transfer of skills to natural environments and interactions with those present in the individual’s life

What did the researchers do?

To obtain a better understanding of the outcomes of EIBI, the authors designed a meta-analysis to examine the data of individuals across studies. A meta-analysis is a tool that combines findings from multiple studies on the same topic in order to estimate overall effect sizes and identify broader patterns across the literature to help us understand overall findings (Field & Gillett, 2010). They included studies where some of the core elements of EIBI were not present, to better compare outcomes of those studies to outcomes of the studies in which core elements of EIBI were present. The authors examined individual participant outcomes in adaptive behavior, intellectual functioning, and autism severity. This is significant, as it is the first meta-analysis to evaluate the effect of EIBI on autism severity. Studies included in the review were those that compared the outcomes of participants in an EIBI-group to participants who received alternative treatments (called the Comparison-group).

To be included in the review, studies were required to have participants who were between the ages of 2 and 7 years with a diagnosis of autism, Asperger’s, or PDD-NOS. Early intensive behavioral intervention needed to include all of the core elements, with the exception of intensity. A minimum of five hours per week was required, which allowed for a comparison of outcomes of children who received low-intensity programming to the outcomes of children who received high-intensity programming (e.g., 40 hours per week). The intervention period for EIBI needed to be at least 12 months. Studies that included participants who were outside of the required age range, received EIBI for less than five hours per week, and had an intervention period for less than 12 months were not included in the review by the authors.

What did the researchers find?

The authors found the following results from the review:

Adaptive behavior: The researchers examined the results of 12 studies that included 294 participants in the EIBI group and 228 in the Comparison group. They found a moderate effect size, indicating a significant impact of EIBI on adaptive behavior. A result such as this indicates that for children who received EIBI, there was significant improvement in their communication, daily living skills, social skills, and motor skills after treatment.

Intellectual functioning: The researchers examined thirteen studies, including 257 participants in the EIBI group and 249 in the Comparison group, were analyzed to determine the effect on intellectual functioning. Results confirmed a large effect size, indicating substantial improvement in intellectual functioning due to EIBI. This means that for children who received EIBI, intelligence test scores were significantly higher after treatment than they were before treatment.

Autism severity: The researchers examined the results of three studies, which had 131 participants in the EIBI group and 37 participants in the Comparison group. They found a large negative effect size, showing a significant reduction in autism severity after receiving EIBI. This means that for children who received EIBI, behaviors (e.g., emotional responses, social interaction) that are identified as symptoms of autism improved after treatment.

To identify potential predictors of outcomes that could have led to the results, the authors analyzed how age, adaptive functioning, and intellectual functioning at the time of intake impacted the improvement that was demonstrated. Through their analysis, they determined that adaptive behavior and intellectual functioning at the time of intake accounted for 12.1% of the change in adaptive behavior. Higher adaptive behavior scores at intake were associated with greater gains. The authors also found that the child’s age at the start of treatment was not responsible for the improvement in adaptive behavior or intellectual functioning. Children who received low-intensity EIBI showed smaller improvements than those who received high-intensity EIBI, for both adaptive behavior and intellectual functioning; as intensity increased, a gradual increase in gains was observed. This means that overall, high-intensity EIBI was responsible for better outcomes.

What are the strengths and limitations of the study?

There are two main strengths of this study. First, the authors used an Individual Participant Data (IPD) meta-analysis. Unlike traditional meta-analyses that rely on group data to identify broader patterns, IPD meta-analyses allow for the evaluation of outcomes for each child (Eldevik et al., 2010). Second, the authors used the evaluation of autism severity as an outcome measure, addressing a notable gap in previous research. Together, these features provide a detailed understanding of the benefits of EIBI.

There are several limitations of this study that should be mentioned. First, children who were included in studies within the analysis were not randomly assigned to groups. This means that there is a chance that the results were influenced by factors other than treatment. Second, researchers who measured outcomes were aware of which group (i.e., EIBI or Comparison) participants belonged to. Future research that includes assessors who are unaware of which groups participants belong to would improve confidence in the findings. Another limitation to consider is that only a small number of reviewed studies used the same tool to measure autism severity. Since the number of participants able to be included in the analysis of autism severity was limited, the authors acknowledge that conclusions should be interpreted with caution. More research should be done using consistent tools to measure autism severity as an outcome measure for EIBI. Lastly, the results of this analysis cannot predict outcomes of individual children. Some children may respond well, and others may not. Effects of treatment are highly individualized, and so the results of this study should not be used to predict individual outcomes.

What do the results mean?

These data provide new insight into the benefits of EIBI not previously demonstrated in the literature. The authors report that their analysis provides strong support for the use of EIBI as an effective treatment for preschool children with ASD. Specifically, they indicate that when provided with high intensity, EIBI improves adaptive behavior, increases intellectual functioning, and reduces autism severity. These are very significant findings. Still, the authors point to the need for high-quality research and suggest several areas where more information is needed. For example, future research could explore the contribution of parent participation, could utilize a broader set of outcome measures, and could systematically assess the differential impact of varying levels of intensity of intervention.

On a broad level, the field does not yet have clear methods for recommending certain levels of intensity. Additionally, it is not apparent whether outcomes today are different from those decades ago. More work is needed to control for bias and to add layers of control within research designs. The bottom line, however, is that this analysis of the literature clearly indicates the positive benefit of EIBI and the superior outcomes of EIBI to control group interventions in all outcome categories (adaptive skills, intellectual functioning, and autism severity).

The authors conclude that EIBI is the preferred treatment for preschool children with autism. This is a significant statement, based on a thorough and systematic review of available evidence. This review can be used to identify future research needs and inspire future research questions. Most importantly, it can be used to bolster recommendations for EIBI and to identify key outcomes that have been demonstrated through its application.

References:

Copeland, L., & Buch, G. (2013). Early intervention issues in autism spectrum disorders. Autism, 3(109), 2-7. http://dx.doi.org/10.4172/2165-7890.1000109

Eldevik, S., Hastings, R. P., Hughes, J. C., Jahr, E., Eikeseth, S., Cross, S., & Lee McIntyre, L. (2010). Using participant data to extend the evidence base for intensive behavioral intervention for children with autism. American journal on intellectual and developmental disabilities, 115(5), 381-405. https://doi.org/10.1352/1944-7558-115.5.381

Field, A. P., & Gillett, R. (2010). How to do a meta‐analysis. British Journal of Mathematical and Statistical Psychology, 63(3), 665-694. https://doi.org/10.3102/10769986017004279

Klintwall, L., & Eikeseth, S. (2014). Early and intensive behavioral intervention (EIBI) in autism. In V. B. Patel, V. R. Preedy, & C. R. Martin (Eds.), Comprehensive guide to autism (pp. 117-137). Springer. https://doi.org/10.1007/978-1-4614-4788-7_129

Reference for this article:

Renshaw, E., & Weiss, M. J. (2026). Research synopsis: Clinically significant outcomes of early intensive behavioral intervention for children with autism spectrum disorders: An individual participant data meta-analysis. Science in Autism Treatment, 23(6).

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