In the current study, we conducted a brief assessment within a multielement design to identify motivating operations (MOs) that increased or decreased the value of negative reinforcement for children with a history of challenging behavior when presented with tasks or demands. For three of the four participants, we identified specific MOs that increased the value of negative reinforcement in the form of escape from nonpreferred tasks. The results demonstrated that the demands themselves were not aversive; rather particular dimensions of the demand (e.g., difficulty, amount). The fourth participant engaged in challenging behavior regardless of the MOs present, which suggested that the demands were aversive to him. Based on the results of the assessment of MOs, each participant was provided an individualized mand to use that abolished the value of negative reinforcement. The mands were provided on picture cards and the contingencies of reinforcement were explained to the participants. Within a reversal design, we then assessed the reinforcers associated with the mand to show their relation to challenging behavior. The individualized mands had the same abolishing effect across all participants, thus showing that the assessment had identified functionally relevant MOs for each participant. Additionally, there was an increase in task engagement, task completion, and accuracy for all participants when matched mands were utilized. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]