Multiple-Stimulus without Replacement Preference Assessment: Reducing the Number of Sessions to Identify Preferred Stimuli

Multiple-stimulus without replacement (MSWO) is a systematic direct assessment method used to identify preferred items and activities that may serve as reinforcers for behavior reduction or skill acquisition programs. DeLeon and Iwata (Journal of Applied Behavior Analysis, 29, 519–532, 1996) validated the original MSWO procedures that consisted of using an average of rank order preference of stimuli across 5-sessions. Carr et al. (Journal of Applied Behavior Analysis, 33, 353–357. doi:10.1901/jaba.2000.33-353, 2000) extended research on the MSWO by suggesting that 1 to 3 sessions may be sufficient to identify preferred stimuli. The current study extended theses results by systematically examining the degree of correlation between 5-session MSWOs and 1, 2, 3, and 4-session MSWOs for nine adults with intellectual disabilities. For edible and activity 5-session MSWOs, 3 sessions were significantly and positively correlated with the outcomes from the 5-session MSWOs for all participants. Results are discussed in terms of potential financial cost and time saving by reducing the number of MSWO sessions, especially in clinical settings where frequent preference assessments are conducted prior to therapy sessions.