“…A small body of research suggests that verbal stimuli or pictures can be used as placeholders for other events, but contingent access to the potential reinforcer is an important feature of valid preference assessments (e.g., Groskreutz & Graff, 2009;Hanley, Iwata, & Lindberg, 1999;Kuhn, DeLeon, Terlonge, & Goyosovich, 2006). Although future investigations may yield valid means to assess protracted events with individuals with disabilities (e.g., community-based outings), research available to date demonstrates that valid outcomes are most likely when selection of specific pictures, verbal stimuli, or tangibles is followed by immediate access to those items.…”