Does the Order of OT and ABA Therapy Matter?

Demographics: Autistic children with identified sensory differences
Key outcome: Both OT-ASI and ABA produced significant gains over no treatment on individualised goals (Goal Attainment Scaling, p < .001) and on daily activities scores, but because the trial never combined or sequenced the therapies it offers no evidence that either one has to come first.
Methodology: A parallel-arm comparative effectiveness trial randomised autistic children with sensory differences to occupational therapy using Ayres Sensory Integration (OT-ASI), to Applied Behaviour Analysis (ABA), or to no treatment, with each therapy delivered as 30 one-hour sessions over 12-15 weeks. The two therapies were compared side by side, not one after the other.
Researchers: Roseann C. Schaaf
Institutes: Jefferson Autism Center of Excellence, Thomas Jefferson University

Limitations:

• No published trial has directly compared starting with OT and then adding ABA against starting with ABA and then adding OT, so the ordering question itself is essentially unstudied.
• The trial delivered each therapy on its own, which is not how most families receive services - in real life OT and ABA usually run at the same time.
• Therapists and caregivers could not realistically be blinded to which therapy a child was receiving, which can inflate reported improvements.
• A published commentary in the same journal has challenged how the trial characterised its ABA arm and how far its equivalence claims can be pushed.
• The best dose, intensity and timing of sensory integration work are still unresolved, and the mechanisms behind any change are not established.

• No research has tested therapy order directly. Despite how confidently the advice is given, there is no published trial comparing 'OT first, then ABA' with 'ABA first, then OT' - the question has not been answered because it has barely been asked.
• When the two therapies were tested head to head, both worked. In a randomised comparative trial, children receiving OT using Ayres Sensory Integration and children receiving ABA both made significant gains on their individualised goals and on daily activities compared with children receiving no treatment.
• That trial ran the therapies separately, not in sequence. Each child got one therapy or neither, so the results say something about whether each therapy helps - not about what order to stack them in.
• The professional literature argues for coordination rather than sequence. A peer-reviewed paper in Behavior Analysis in Practice on collaboration between behaviour analysts and occupational therapists frames the central problem as the two professions working in isolation and sometimes at cross purposes, and calls for shared assessment and aligned goals.
• The two fields genuinely disagree about sensory-based intervention. Behaviour analysts have long questioned the evidence base for sensory integration, and that disagreement - not a settled ordering rule - is what sits underneath much of the conflicting advice parents receive.
• The common rationale for 'OT first' is about readiness, not proven sequence. The reasoning is that a child who is overwhelmed by sensory input cannot engage with structured learning, so regulation should come first. It is a plausible clinical argument, but it has not been tested as a sequencing question in a controlled trial.
• Total therapy load is a real and measurable factor. Research on intervention intensity and on caregiver stress shows that highly stressed parents have more difficulty carrying out their children's behaviour plans, which makes how much therapy a family can sustain a practical constraint on any plan.

• If a provider tells you there is one correct order, ask what that is based on. The honest answer available from current research is that the sequencing question has not been studied - so a confident claim in either direction is a clinical opinion, not a research finding.
• A more answerable question than 'which comes first' is 'what is getting in the way right now'. If sensory distress is the thing stopping your child from eating, sleeping, dressing or coping at school, that argues for prioritising OT. If the most pressing issue is communication or a behaviour that is unsafe, that argues for prioritising behavioural support.
• Prioritising is not the same as sequencing. Choosing where to put the most hours this term does not mean the other therapy has to wait until the first one is 'finished' - most children who receive both get them concurrently.
• Coordination is the part the evidence actually supports. Whether therapies run together or one leads, the recurring recommendation across the literature is shared goals and regular communication between the OT and the behaviour analyst, so your child is not being taught contradictory things in two rooms.
• You are allowed to weigh capacity. Waitlists, insurance coverage, travel, cost and your child's tolerance for a long therapy week are legitimate inputs into the decision - and since no order is proven superior, starting with whichever quality service you can actually access is a reasonable choice.
• Watch your own child rather than the schedule. Because the research cannot tell you the right order, the most useful evidence is your child's own response over the first few months - what is improving, what is getting harder, and whether the total load is sustainable for your family.

• This summary describes what the research does and does not establish. It is not a recommendation about your child's therapy plan, and it cannot substitute for an assessment by clinicians who know your child.
• Absence of evidence about ordering is not evidence that order never matters. It is entirely possible that sequence matters a great deal for some children - particularly those with severe sensory distress - but that possibility has not yet been tested.
• The head-to-head trial is a single study of children specifically selected for sensory differences, and its conclusions about ABA have been formally contested in a commentary published in the same journal. It should be read as one useful data point, not a verdict.
• 'OT' and 'ABA' are both broad labels covering very different practices. Ayres Sensory Integration as delivered in a research protocol is not the same as every service marketed as sensory OT, and ABA ranges widely in style, intensity and quality.
• Much of the readily available material on this question is published by therapy providers who deliver one or both services, so it should be read with that commercial interest in mind.
• ABA itself remains contested, particularly by many autistic adults, on grounds that go beyond effectiveness data. Families weighing these therapies may reasonably factor in those concerns alongside the research.

• A Comparative Trial of Occupational Therapy Using Ayres Sensory Integration and Applied Behavior Analysis Interventions for Autistic Children — Schaaf et al., 2025, Autism Research, 18(10), 2120-2134
• Clarifying the ABA Comparison and Equivalence Claims in Schaaf et al. (2025) — Chang, 2025, Autism Research (commentary)
• Collaboration between Behavior Analysts and Occupational Therapists in Autism Service Provision: Bridging the Gap — Behavior Analysis in Practice, 2021
• A Review of 'Collaboration between behavior analysts and occupational therapists in autism service provision' — Association for Science in Autism Treatment
• An evaluation of the effects of intensity and duration on outcomes across treatment domains for children with autism spectrum disorder — Translational Psychiatry, 2017
• Sensory-based Interventions — Association for Science in Autism Treatment

• Joint Attention: Why It Matters in Early Development — Social
• Sugar and Neurodevelopment: What the Evidence Says for Autism and ADHD — General
• Understanding Sensory Issues and Humming in Autistic Children: What Caregivers Need to Know — Sensory

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This summary was prepared by the Curioler research agent. It is not medical advice. Always consult a qualified professional before making decisions about your child's care.