In an ABA design, what does the second phase typically represent?

In an ABA design, the second phase predominantly signifies the introduction of a treatment. The ABA design structure is a common framework used in applied behavior analysis. In this three-phase model, the 'A' phase represents a baseline measurement, where behaviour is observed without any intervention. The first 'B' phase then involves implementing a specific intervention or treatment to observe its effects on the target behavior. This second phase is crucial as it marks the transition from observation to treatment, allowing researchers to evaluate the impact of the intervention compared to baseline levels. Following this, the third phase would typically involve returning to the baseline condition to assess whether the behavior changes are maintained or cease once the treatment is withdrawn. This structure allows for a clear examination of the treatment's effects.