Assent Withdrawal and FCT in ASD: Frequently Asked Questions

1. What is the difference between assent and informed consent in ABA practice?

Informed consent is the formal authorization provided by a legally competent adult—typically a parent or guardian—for treatment to proceed. Assent is the client's own expression of willingness to participate, regardless of their legal consent status. The BACB Ethics Code (2022) Section 2.04 requires BCBAs to attempt to obtain assent from clients who cannot provide informed consent, using methods adapted to their communicative capabilities.

2. Why would letting a child withdraw from tasks reduce problem behavior?

Dawson et al. (2026) found that FCT teaching procedures work by making a functional communicative response more efficient than the problem behavior at producing the desired consequence. When a child can reliably exit a task by using an assent withdrawal response, the function previously served by problem behavior is met through a more socially appropriate channel—and problem behavior rates decrease.

3. What forms can an assent withdrawal response take?

Any form within the client's current communicative repertoire: a picture card labeled 'break,' a sign, a verbal phrase ('I need a break'), an AAC device output, or a gesture. The form should be selected based on what the client can produce reliably and what staff can recognize consistently. As the client's communicative repertoire expands, the assent withdrawal response can be upgraded to a more sophisticated form.

4. How do you prevent the assent withdrawal response from being used to avoid all work?

Structure the break schedule from the beginning: define break duration, define how many breaks are available per session, and define the expectation for return to task. Use thinning schedules to gradually increase the demand density between assent withdrawal responses as the client demonstrates stable use of the response. Kok et al.

(2026) found that structured intervention parameters with clear contingency definitions produce more consistent outcomes than loosely specified procedures.

5. How do you train staff to honor the assent withdrawal response consistently?

Behavioral skills training (BST): describe the response form and the expected staff behavior, model the correct response in role play, rehearse with the staff member until mastery, and provide performance feedback in actual sessions. Written protocols alone are insufficient. Document staff training completion and conduct periodic fidelity checks to ensure the procedure is being implemented as designed.

6. Does assent withdrawal FCT work for all functions of problem behavior?

It is most directly indicated for escape-maintained problem behavior, where the function is already to exit demands. For attention-maintained or tangible-maintained problem behavior, assent withdrawal is still an ethical component of treatment design—but the replacement behavior intervention should target the specific maintaining function. In mixed-function cases, both assent-based and function-specific FCT components may be needed.

7. How should assent withdrawal procedures be documented in the behavior support plan?

Document the assent withdrawal response form, the consequence that reliably follows it, the session structure parameters (break duration, frequency limit), the training requirements for staff, and the data system for tracking response frequency. Include a section on how to respond if the client refuses to return from a break—establishing that protocol in advance prevents ad hoc decisions that undermine the consistency of the system.

8. What does caregiver training on assent look like?

Pichardo et al. (2026) found that implementation accuracy depends on how explicitly instructions are communicated. For assent withdrawal, caregiver training should include direct behavioral rehearsal of recognizing and honoring the assent response, specific guidance on what not to do when the child withdraws, and a framework for interpreting withdrawal as communication rather than defiance.

9. What are the risks of not including assent withdrawal provisions in behavior support plans?

Without a recognized assent withdrawal mechanism, clients who wish to exit tasks have only two options: comply or engage in problem behavior. When compliance is consistently aversive and problem behavior is consistently effective at producing escape, the problem behavior is strengthened. The resulting pattern—escalating severity, broadening generalization, treatment resistance—is more difficult to address than an escape function that has been captured by a communicative response from the outset.

10. How does assent withdrawal change over time in a successful FCT program?

As the client's communicative repertoire expands and as the demand context becomes more predictable and preferred, spontaneous assent withdrawal rate typically decreases. The goal is not to eliminate the option but to make the client's engagement with intervention increasingly voluntary. Clients who engage because they choose to engage acquire skills more robustly and generalize more broadly than those who engage only because escape is unavailable.