A preference assessment is conducted to identify potential reinforcers.  Note, we don’t know that these things are actually reinforcing until we see if applying the items increases a behavior.  To determine if a potential reinforcer is actually reinforcing, we can do a reinforcer assessment.

Ways to identify potential reinforcers:

• Ask the person about their preferences.  This is an indirect method.  It can also involve asking care givers, parents, teachers or friends about the person’s preferences.  This method can be done by asking open-ended questions, choice format or rank-ordering.
• Another method is to offer a pre-task choice.  Ask the person before they work on a task what they would like to “earn” for completing the task.  The participant can pick from 2 to 3 items presented.
• Free operant observation is a way to identify potential reinforcers.  Basically, stay observant and see what the individual gravitates to and plays with in an unrestricted room.  The total duration of the time that the person engages with each item or stimulus is recorded.  The longer that the individual engages with the sitmulus, the stronger the case that the item is preferred.  This method can be contrived (contrived free operant observation), where the environment is seeded with hypothetically reinforcing items, or conducted in a natural environment (naturalistic free operant observation) such as a child’s play room.
• Trial-based methods are formal methods to determine potential reinforcers.
  • Single Stimulus is also called successive choice method.  This is the most basic trial-based method.  Basically, a stimulus is presented and the person’s reaction to it is noted.  This is helpful with individuals who may have trouble between selecting between two or more items.
  • Paired Stimuli is also called the forced-choice method.  Each trial consists of presenting two items and recording the person’s choice of the two.  Data is recorded on how many times an item was chosen and then items are rank ordered.  This method takes the most time to implement and is said to be the most accurate.
  • Multiple Stimuli is where many items are presented at one time.  This is an efficient method.  There are two variations:  Multiple Stimuli with Replacement (MSWR) and Multiple Stimuli without Replacement (MSWOR).  In MSWR, the item chosen remains in the array and all other items that were not selected are replaced by other items.  In MSWOR, the item chosen is taken out of the array and the array diminishes in size on each selection.  MSWOR is the fastest method.