Jump to Section: [Single Item Method] [Paired Stimulus Method] [Multiple Stimulus Method] [Create Preference Assessment]
Preference Assessment Types
Currently, Catalyst offers four main types of preference assessments including Single Stimulus, Paired Stimulus (Forced-Choice), Multiple-Stimulus with Replacement (MSW), and Multiple-Stimulus without Replacement (MSWO).
Single Item Method
Single Item presentation method of conducting Stimulus Preference Assessments (SPAs) is also referred to as Successive Choice Assessments. Stimuli, such as objects or activities, are presented sequentially, one at a time, in random order. Typically, duration measures of interaction or engagement with each stimulus are used to identify highly preferred stimuli.
Catalyst-specific details for Single Item Stimulus Assessments:
- Stimulus Array - Items are presented one at a time and only once during each session.
- Scoring/Results - Results are presented as the duration of engagement with the item.
- Termination Criteria - The session is terminated when all trials are completed.
Paired Stimulus Method
The Paired Stimulus method of conducting Stimulus Preference Assessments (SPAs) is sometimes referred to as a Forced Choice Assessment. Stimuli, such as objects or activities, are presented sequentially, in pairs, in random order. Every stimulus is presented systematically with every other stimulus at least twice (ideally, once on the left and once on the right to control for position bias). The individual’s choice is recorded following each presentation, and stimuli can then be ranked based on selection percentage (selections/presentations X 100).
NOTE: Paired Stimulus Assessments are generally more time-consuming than Single Assessments; however, Paired Stimulus Assessments can compare stimuli with one another to establish relative preferences.
Catalyst-specific details for Paired Stimulus Assessments:
- Stimulus Array - Items are presented two at a time and compared with every other stimulus twice (once with the item on the left and once with the item on the right to control for position bias).
- Scoring/Results - Results are presented as a percentage of times the item was selected (# of times the item was selected/# of times the item was presented x100). The number of trials during the assessment is determined by the number of stimulus items being assessed (taking into consideration that every item is presented with every other item twice).
- Termination Criteria - The session is terminated when all trials are completed.
Multiple Stimulus Method
The Multiple Stimulus Method of conducting Stimulus Preference Assessments (SPAs) may reduce the time required for conducting a SPA that compares stimuli by presenting multiple stimuli at once, rather than in pairs. In this type of assessment, stimuli are presented in groups of three or more, with or without replacement.
In a Multiple Stimulus WITH Replacement (MSW), when a stimulus is selected, it is replaced on the next presentation. For example, if a food item is consumed, an identical food item replaces the first in the subsequent stimulus array.
In a Multiple Stimulus WITHOUT Replacement (MSWO), the selected stimulus is withheld (not replaced) on the subsequent presentation. In other words, the array decreases by one stimulus item after each presentation until each has been selected or the individual fails to select one of the arrays.
Catalyst-specific details for Multiple Stimulus WITH Replacement (MSW) Assessments:
- Stimulus Array - All stimuli being assessed are presented in each trial. After each trial, the stimulus selected is replaced and the item on the far right is moved to the first position on the left and all other items shift to the right.
- Scoring/Results - Results are presented as the percentage of times the item was selected (# of times the item was selected / # of times the item was presented X 100). The number of trials during the assessment is determined by the number of stimulus items being assessed (e.g., if 5 items are being assessed, the assessment will contain 5 trials).
- Termination Criteria - The session is terminated when all trials are completed or if no item is selected during a trial.
Catalyst-specific details for Multiple Stimulus WITHOUT Replacement (MSWO) Assessments:
- Stimulus Array - All stimulus items are presented during the first trial of the assessment. After an item is selected, the item is NOT replaced so the stimulus array decreases by one. After each trial, the stimulus on the far right is moved to the first position on the left and all other items shift to the right.
- Scoring/Results - Results are presented as point values. The first item selected is given the max value. Max value is determined by the number of items being assessed. For example, if 8 items are being assessed, then the max point value is 8. The second item selected is scored as 7 points and so forth. The number of trials during the assessment is determined by the number of stimulus items being assessed (e.g., if 8 items are being assessed, the assessment will contain 8 trials).
- Termination Criteria - The session is terminated when all items have been selected or no item is selected.
Create Preference Assessment
In order to collect data on the app, users must first create a Preference Assessment in the Student Portal. The Assessments tab is also available on tablet devices.
Access the Preference Assessment subtab from the Assessments tab in the Student Section.
- Scroll to the bottom of the page and click Setup New Preference Assessment.
- Enter Preference Assessment Information:
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*Denotes Required Field
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- Allow Settings Override - Enabling will allow users to change the above settings directly from the app.
- Select Preference Items - Click in the field to select desired Preference items.
3. Click Save.
NOTE: The new Assessment will display in the list of active Assessments on both the portal and the app.