Multiple Stimulus Without Replacement Preference Assessments: An Examination of the Relation Between Session Number and Effectiveness

Abstract

Multiple stimulus without replacement (MSWO) preference assessments have been demonstrated to effectively identify reinforcers for individuals with severe to profound disabilities, but it may be possible to make the procedures more efficient by decreasing the number of array presentations. This investigation presents one case study that compared single-, three-, and five-session MSWO formats to determine if reinforcers could be reliably identified with all three formats for one student with pervasive developmental disability not otherwise specified (PDD-NOS). Using a concurrent-operants design embedded in a reversal design, subsequent reinforcer assessments indicated that a reinforcer was identified with each assessment format. Directions for future research and procedural limitations will be discussed.