Choice set
A choice set is one scenario, also known as a treatment, provided for evaluation by respondents in a choice experiment. Responses are collected and used to create a choice model. Respondents are usually provided with a series of differing choice sets for evaluation.
The choice set is generated from an experimental design and usually involves two or more alternatives being presented together.
Example of a choice set
A choice set has the following elements.
Alternatives
A number of hypothetical alternatives, Car A and Car B in this example. There may be one or more Alternatives including the 'None' Alternative.
Attributes
The attributes of the alternatives ideally are mutually exclusive and independent. When this is not possible, attributes are nested.
Levels
Each Attribute has a number of possible levels that the attributes may range over. The specific levels that are shown are driven by an experimental design. Levels are discrete, even in the case that the attribute is a scalar such as price. In this case, the levels are discretized evenly along the range of allowable values.
Choice task
The respondent is asked a choice task. Usually this is which of the alternatives they prefer. In this example, the Choice task is 'forced'. An 'unforced' choice would allow the respondents to also select 'Neither'.
The choice task is used as the dependent variable in the resulting choice model