Therapy Decision Guide
DTT is a core component of IBI and ABA services eligible under OAP core clinical services. When delivered by BACB-certified practitioners, it is funded through the childhood budget.
Ask any prospective provider which of these credentials they hold, and confirm the credential with the relevant regulatory college before starting.
Each discrete trial follows a precise five-part sequence. The therapist presents a clear instruction or cue. A prompt helps the child respond correctly if needed. The child produces a response. The therapist delivers a consequence — reinforcement for correct responses or correction for errors. A brief inter-trial interval separates consecutive trials.
DTT is highly effective for teaching foundational skills. These include matching, imitation, receptive and expressive language, and pre-academic concepts. Skills are taught in massed trials to build fluency. Once mastered in structured settings, skills are generalized to natural environments through planned transfer procedures.
Data collection during every trial drives clinical decisions. Therapists graph response accuracy, prompt levels, and rate of acquisition. This precision allows rapid identification of effective teaching strategies and early detection of skill plateaus requiring program modification.
Lovaas (1987) published the landmark study demonstrating that 47% of young autistic children receiving 40 hours per week of DTT-based intervention achieved typical intellectual and educational functioning. Smith, Groen, and Wynn (2000) replicated these findings in a controlled trial published in the American Journal on Mental Retardation.
The National Autism Center's National Standards Project (2009, updated 2015) classified DTT as an "established" evidence-based practice. The National Clearinghouse on Autism Evidence and Practice (NCAEP, 2020) similarly identifies DTT as meeting criteria for evidence-based status across multiple skill domains.
In Ontario, DTT is the primary teaching methodology within Intensive Behavioural Intervention programs. IBI has been funded through Ontario's autism services since 2000. Under the current OAP framework, families access DTT-based services through their childhood budget allocation.
Ontario requires that IBI and ABA programs be supervised by BACB-certified behaviour analysts. Registered behaviour technicians deliver direct therapy under BCBA supervision. The Ontario Association for Behaviour Analysis (ONTABA) maintains a provider directory for families seeking qualified DTT practitioners.
Lovaas (1987)
Behavioral treatment and normal educational and intellectual functioning in young autistic children. Journal of Consulting and Clinical Psychology, 55(1), 3-9.
Smith, Groen & Wynn (2000)
Randomized trial of intensive early intervention for children with pervasive developmental disorder. American Journal on Mental Retardation, 105(4), 269-285.
National Autism Center (2015)
Findings and conclusions: National Standards Project, Phase 2. Randolph, MA: National Autism Center.
Written by Spencer Carroll
Founder & Autism Advocate
Evidence on this page
Key claims are paired with their source, evidence tier, and verification date so readers can inspect the public record directly.
Early Start Denver Model (ESDM) delivered to children aged 18–30 months produced significant gains in IQ, adaptive behaviour, and autism severity — some children no longer met diagnostic criteria at follow-up
Cochrane systematic review finds evidence that early intensive behavioural intervention (EIBI) may produce positive effects on adaptive behaviour and communication for young children with ASD (low certainty of evidence)
WHO recommends accessible, community-based early interventions for children with autism — timely evidence-based psychosocial interventions improve communication and social engagement
89,799
children are registered in the Ontario Autism Program
23%
Only 20,633 children have active funding agreements — less than one in four