Irreversibility occurs when the behavior change observed during an intervention phase cannot be reversed or returned to baseline levels when the intervention is withdrawn In this scenario the clients addition fluency improved from 5 to 10 correct responses per minute during the intervention B1 but when the intervention was withdrawn A2 the performance did not return to the original baseline level of 5 instead it remained at 10 This indicates that the skill was acquired and maintained making it impossible to demonstrate experimental control through withdrawal Academic skills like math reading and motor skills are common examples of behaviors that can be irreversible once learned Lets consider the other options Multiple treatment interference is typically associated with alternating treatments designs where the effects of one treatment might carry over and influence the effects of subsequent treatments While sequence effects can occur in ABAB designs the primary issue described here is the failure of the behavior to return to baseline which is the definition of irreversibility The math intervention was not effective is incorrect The intervention was effective in increasing the clients performance from 5 to 10 correct responses per minute The problem is not a lack of effectiveness but rather the inability to reverse the effect A functional relation between the intervention and behavior was demonstrated is incorrect A functional relation in an ABAB design is demonstrated by the behavior reliably reversing decreasing when the intervention is withdrawn and then reliably reemerging increasing when the intervention is reintroduced Since the behavior did not reverse experimental control and thus a clear demonstration of functional relation via this design could not be established