What trials compare ABA therapy and ESDM for measurable gains in autism? 

The NHS explains that support for autistic children should focus on communication, daily life and wellbeing rather than trying to change who a child is. In line with this, NICE recommends early developmental and behavioural support but does not endorse brand name programmes such as ABA, EIBI or the Early Start Denver Model (ESDM). ESDM is usually described as part of a wider naturalistic developmental behavioural intervention (NDBI) family that uses applied behaviour analytic principles in a play based, relationship focused way. 

Understanding the concept 

Applied Behaviour Analysis (ABA) is a behaviour based framework that looks at how the environment influences behaviour and how new skills can be taught in small, structured steps. Classic early intensive behavioural intervention programmes use one to one teaching, clear instructions and systematic reinforcement to build skills in communication, learning and self care. 

ESDM is a specific manualised programme for very young autistic children that blends developmental science with behaviour analytic techniques. Sessions are play based, follow the child’s interests and embed learning opportunities into natural routines. Parents are coached to use ESDM strategies at home so that practice continues between sessions. In research and in the NIHR evidence synthesis, ESDM is usually grouped with other NDBIs that share these naturalistic and developmental features. 

Both ABA and ESDM rely on reinforcement, prompting and careful observation, but ESDM gives more weight to shared attention, play and co regulation, whereas traditional ABA has historically been more therapist led and highly structured. 

Evidence and impact 

Direct head to head trial data that compares ABA and ESDM under the same conditions are surprisingly limited. One of the few large randomised controlled trials comes from Yang et al. 2023 who compared a mixed ESDM package with a mixed discrete trial ABA programme in 249 autistic toddlers and preschool children over 12 weeks of equal intensity intervention (25 hours per week) plus parent coaching. The ESDM based group showed greater gains than the discrete trial ABA group in gross motor and personal social skills across ages, and in language for several subgroups. Both groups improved, but the pattern of change tended to favour the ESDM approach on these developmental measures. 

Other trials offer indirect comparisons. Early ESDM research in PubMed led by Dawson et al. (2010) randomised toddlers to two years of intensive ESDM or referral to community services, which often included eclectic programmes with some ABA elements. Children receiving ESDM had larger gains in IQ, language and adaptive behaviour than those in community treatment, and parents reported meaningful changes in everyday functioning. 

A more recent multicentre trial in BMJ by Geoffray et al. (2025) in Europe found similar patterns, with ESDM associated with better trajectories in cognition and language than usual care, although effects on autism symptoms and adaptive skills were more modest, 

Meta-analyses report moderate effect sizes but rate the overall certainty of evidence as low to very low in many domains. For example, Fuller and Kaiser (2020) found moderate improvements in communication and social skills following NDBI-based interventions, but assessed the overall evidence quality as low due to small samples and methodological limitations. 

Taken together, the research suggests that: 

• both ABA based programmes and ESDM can improve measurable outcomes such as cognition, language and adaptive functioning compared with generic community care 

• when ABA and ESDM style approaches are compared directly at similar intensity, ESDM or other NDBIs may show advantages for language and social development, at least over the short term 

However, most trials are relatively short, long term follow up is sparse and evidence about wider outcomes such as wellbeing, identity and family stress is limited. 

Practical support and approaches 

For families, the NHS focuses less on which brand of programme to choose and more on practical support: simple language, visual supports, structured routines and access to speech and language therapy. Local early years teams often use play based sessions, small group work and parent training that share features with both ABA and ESDM style interventions, without always using those labels. 

In ESDM research, therapists and parents typically work together for 15 to 25 hours per week, with learning embedded in play and daily activities. In early intensive ABA, programmes may offer 20 to 40 hours of mostly one to one teaching. In real services, intensity is often lower than in trials, and approaches are blended. The National Autistic Society stresses that no single intervention suits every child and that programmes should support communication, confidence and participation rather than aiming to cure autism. 

Challenges and considerations 

There are important caveats to the evidence on ABA and ESDM trials. 

Most trials involve preschool children. NICE guidance for autistic adults focuses instead on adapted psychological therapies, skills for daily living and support for mental and physical health. Findings from toddler and preschool studies cannot simply be applied to older children or adults. 

Methodological limitations are common. Control conditions often vary widely, outcome measures differ between studies and blinding can be difficult. Meta analyses report moderate effect sizes but also rate the overall certainty of evidence as low to very low in many areas (Reichow et al.; Fuller and Kaiser 2020). 

Finally, quantitative gains in IQ or language scores do not capture all aspects of autistic experience. Autistic led research has raised concerns about how some early intensive interventions are delivered, particularly if they focus on compliance rather than communication and comfort. The National Autistic Society emphasises that support should respect autistic communication styles, use clear and concrete language and avoid approaches that feel overwhelming or invalidating. 

How services can help 

In the United Kingdom, families are encouraged by the NHS to seek help through their GP, health visitors or local autism pathways rather than trying to choose a programme in isolation. NICE recommends that children have access to social communication interventions, parent mediated support and, where needed, positive behavioural support, but it does not require commissioners to fund specific brands such as ABA or ESDM. 

When discussing options with local teams, it can be helpful to ask: 

• how therapy will support communication, play and everyday participation 

• how parents will be involved and coached 

• how the child’s comfort, preferences and sensory needs will be taken into account 

• how progress and potential difficulties will be monitored over time 

These questions matter more than the specific label on a programme. 

Takeaway 

Trials comparing ABA and ESDM show that both approaches can lead to measurable gains for autistic children, particularly in cognition, language and early adaptive skills, with some studies suggesting advantages for ESDM style NDBIs in communication and social development under matched intensity. At the same time, the NHS and NICE focus on early, individualised developmental and behavioural support rather than endorsing a particular brand. For families, the most important question is not whether a programme is called ABA or ESDM, but whether it is collaborative, autism informed and genuinely helps the child communicate, feel safe and participate in daily life. 

If you or someone you support would benefit from early identification or structured autism guidance, visit Autism Detect, a UK-based platform offering professional assessment tools and evidence-informed support for autistic individuals and families.