ABA Design — ABA Reversal Design
ABA Reversal Design · Also known as: reversal design, withdrawal design, ABA withdrawal design
The ABA design is a single-subject experimental design that demonstrates experimental control through three sequential phases: a baseline phase (A1), an intervention phase (B), and a return-to-baseline withdrawal phase (A2). By removing the intervention in the final phase and observing whether behavior reverts toward baseline levels, researchers establish a functional relationship between the treatment and the target behavior for an individual participant.
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When to use it
Use the ABA design when you need to demonstrate a functional relationship between a specific intervention and a target behavior in an individual participant, and when the behavior is expected to be reversible after the intervention is withdrawn. It is appropriate in applied behavior analysis, special education, rehabilitation, and clinical psychology when group designs are impractical (rare conditions, small N, individualized interventions). Do not use the ABA design when withdrawal of the intervention poses ethical risk — for example, when the target behavior is self-injury, academic skill acquisition (learned skills may not reverse), or any situation where withholding a beneficial treatment during A2 would harm the participant. In those cases, prefer the ABAB design or a multiple baseline design.
Strengths & limitations
- Provides clear, within-subject demonstration of a causal relationship without a separate control group.
- Appropriate for studying rare behaviors or small populations where group experiments are infeasible.
- Replication logic within a single participant controls for many maturation and history confounds.
- Continuous measurement yields rich temporal data on behavioral dynamics, not just pre-post snapshots.
- Low participant burden compared with multi-group randomized trials; each person serves as their own control.
- Findings are specific to the individual participant; statistical generalization to a population requires systematic replication across multiple participants and settings.
- The design is unsuitable when the target behavior is irreversible (e.g., acquired academic skills, motor learning) — a non-reversal in A2 confounds interpretation.
- Ends in a withdrawal phase, meaning the participant concludes the study without the intervention active; this raises ethical concerns for beneficial treatments.
- Visual analysis of time-series data requires training and can be subject to analyst bias; inter-rater reliability checks are necessary.
Frequently asked
What is the difference between the ABA and ABAB designs?
Both are reversal designs. The ABA design has three phases and ends with withdrawal of the intervention. The ABAB design adds a second B (intervention) phase, ending with the treatment active. ABAB provides stronger causal evidence through a second replication of the effect and is ethically preferable when the intervention is beneficial, because the participant ends the study receiving the treatment.
How do I know when the baseline is stable enough to proceed?
Common criteria require at least three consecutive data points with no systematic trend in the direction predicted for the intervention, and with variability (the range of scores) that is small enough not to obscure an anticipated effect. If baseline trends upward and you predict an upward intervention effect, wait for the trend to flatten or reverse before introducing B.
Can I analyze ABA data statistically instead of using visual analysis?
Yes, visual analysis is standard and required, but effect-size statistics can supplement it. Widely used metrics include Tau-U (which accounts for baseline trend), the percentage of non-overlapping data (PND), and the improvement rate difference (IRD). These metrics help quantify the magnitude of the effect and support comparisons across studies in meta-analyses.
Is the ABA design the same as an ABAB or a withdrawal design?
The terms reversal design and withdrawal design are often used interchangeably for ABA-family designs. Technically, a reversal involves actively reinstating baseline conditions (removing the reinforcer), while a withdrawal simply discontinues the intervention. In practice, most researchers treat ABA and withdrawal design as synonyms. An ABAB design is a specific extension that re-introduces the intervention after the second baseline.
Can I generalize the findings from an ABA study to other people?
Not directly. Single-subject designs establish a functional relationship for the individual studied. Generalization to other individuals and settings is achieved through systematic replication — repeating the study with different participants, therapists, or settings. A pattern of consistent effects across replications, often reported in literature reviews or meta-analyses, supports broader conclusions.
Sources
- Baer, D. M., Wolf, M. M., & Risley, T. R. (1968). Some current dimensions of applied behavior analysis. Journal of Applied Behavior Analysis, 1(1), 91–97. DOI: 10.1901/jaba.1968.1-91 ↗
- Cooper, J. O., Heron, T. E., & Heward, W. L. (2020). Applied Behavior Analysis (3rd ed.). Pearson. ISBN: 978-0134752556
How to cite this page
ScholarGate. (2026, June 3). ABA Reversal Design. ScholarGate. https://scholargate.app/en/experimental-design/aba-design
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
- AB DesignExperimental design↔ compare
- ABAB designExperimental design↔ compare
- Alternating Treatments DesignDisability Studies↔ compare
- Changing Criterion DesignDisability Studies↔ compare
- Multiple Baseline DesignExperimental design↔ compare
- Single-Subject Experimental DesignExperimental design↔ compare