"A variety of procedures used to determine the stimuli that a person prefers, the relative preference values (high versus low) of those stimuli, the conditions under which those preference values remain in effect, and their presumed value as reinforcers" (Cooper, Heron, & Heward, 2007, p. 705).

Also called a "successive choice" method. A stimulus is presented one at a time. Approaches to the items are recorded. Preference is based on whether or not individual approached item. (Pace, Ivancic, Edwards, Iwata, & Page, 1985)

Also called a "forced choice" method. Consists of the simultaneous presentation of two stimuli. The observer records which of the two stimuli the learner chooses. Presentations continue until all stimuli are paired with each other stimulus. A hierarchy can then be formed using the choices. (Fisher, Piazza, Bowman, Hagopian, Owens, & Slevin, 1992).