A functional behavioral assessment was conducted to identify the maintaining function(s) of aberrant behaviors displayed by a 6-year-old diagnosed with multiple disabilities. The assessment included indirect measures such as interviews, rating scales, and direct observations such as antecedent, behavior, consequence (A-B-C) charting. These assessments allowed the teacher to develop a hypothesis about the maintaining function of the aberrant behaviors. A functional assessment was not conducted. Instead, treatment was initiated quickly based on an abbreviated analysis. The results showed decreased rates of aberrant behavior following the implementation of the functional assessment based intervention; however, occurrences of aberrant behavior were not eliminated. Additional analyses suggested that changes in routine may be analogous to high demand situations that act as setting events for aberrant behavior. The results are discussed in terms of developing strategies for identifying events at home and in the community that may influence the occurrence of aberrant behavior.