“…These include: (1) direct observation of a client’s interaction with an array of stimuli, (2) data collection on that interaction, (3) a comparison of relative interaction with the stimuli under observation. Existing preference assessments differ in the manner in which stimuli are presented (e.g., singly or in pairs; Fisher et al, 1992; Pace, Ivancic, Edwards, Iwata, & Page, 1985), the manner in which data are collection (e.g., duration recording or trial-by-trial choices; DeLeon & Iwata, 1996; Roane, Vollmer, Ringdahl, & Marcus, 1998), and the range of stimuli identified as differentially preferred (Hanley, Iwata, Lindberg, & Conners, 2003). …”