A high-probability request sequence in ABA presents a short series of requests the person has recently completed often, followed by a request completed less often under comparable conditions. The applied procedure must use individualized evidence, accessible responses, ordinary supports, a clear response window, and meaningful consequences. Families should also see assent, dissent, burden, partner behavior, lower-probability outcomes, and a stop rule.
Map the high-probability request sequence ABA uses
Write each request exactly, the eligible setting, required supports, response window, and consequence. Identify the lower-probability request separately. A request is high probability only for this person and context during a stated screening period.
Keep the evidence in proportion
A small medical-examination study used three screened high-probability requests before each examination request with two autistic children. The procedure increased measured completion in that study. Its participants, tasks, sequence, and consequences do not create a universal family protocol.
Separate the procedure from the theory
The behavioral-momentum study examined reinforcement quality, high-probability sequences, and resistance to change. The applied sequence is often described with momentum language, while formal persistence analysis requires its own baseline and disruption measures. The BACB outline supplies examination scope rather than a recipe.
Protect choice and access
The Ethics Code addresses client involvement, consent and assent when applicable, risk, and evaluation. ASHA says AAC users should always have access to their tools. The sequence cannot turn communication, basic needs, pain, or emergency help into earned outcomes.
A practical example
Tessa chooses two familiar warm-up actions before opening a new art tool. Across eight eligible trials, both warm-ups are completed in 7/8 and the art-tool step in 5/8. The team reports each count, Tessa's comfort rating, one withdrawal, and whether the warm-ups changed time or burden.
Questions families can use
Which requests were screened? Are conditions comparable? What follows each response? Can the person pause or decline? Which lower-probability outcome matters? How will the team know when the sequence adds burden or stops helping?
Sources
- Behavior Analyst Certification Board, BCBA Test Content Outline, 6th edition
- Shillingsburg and colleagues, Increasing Compliance With Medical Examination Requests Directed to Children With Autism
- Davis and Reichle, Variant and Invariant High-Probability Requests
- Mace and colleagues, Effects of Reinforcer Quality on Behavioral Momentum
- Behavior Analyst Certification Board, Ethics Code for Behavior Analysts
- American Speech-Language-Hearing Association, Augmentative and Alternative Communication
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