Which preference assessment is defined by selected items not being returned to the array?

The preference assessment defined by selected items not being returned to the array is the multiple-stimulus without replacement method. In this type of assessment, individuals are presented with a set of items, and once an item is chosen, it is removed from the array, meaning it will not be available for selection in subsequent trials. This method allows practitioners to understand an individual's preference hierarchy as the assessment progresses because the items that have already been selected can indicate which items are more preferable compared to the remaining options.

In contrast, other preference assessment methods involve different procedures. For instance, free-operant preference assessments allow individuals to interact with items freely without a structured selection process, so items remain available throughout the session. Paired-stimulus assessments involve presenting two items at a time and recording selections, but items remain available for future pairings. The single-item duration approach focuses on measuring how long an individual engages with a single item over time, rather than evaluating preference through a selection process like that seen in multiple-stimulus without replacement.