Modeling and Multivariate Methods - SAS

Chapter 16 Performing Choice Modeling 405
Example: Pizza Choice
Example: Pizza Choice
Suppose that you are supplying pizza for an airline. You want to find pizza attributes that are optimal for the
flying population. So, you have a group of frequent flyers complete a choice survey. In order to weigh the
importance of each attribute and to determine whether there are any interactions between the different
attributes, you give them a series of choices that require them to state their preference between each pair of
choices. One pair of choices might be between two types of pizza that they like, or between two types of
pizza that they do not like. Hence, the choice might not always be easy.
This example examines pizza choices where three attributes, each with two levels, are presented to the
subjects:
• crust (thick or thin),
• cheese (mozzarella or Monterey Jack),
• topping (pepperoni or none).
Suppose a subject likes thin crust with mozzarella cheese and no topping, but the choices given to the
subject are either a thick crust with mozzarella cheese and pepperoni topping, or a thin crust with Monterey
Jack cheese and no topping. Since neither of these pizzas is ideal, the subject has to weigh which of the
attributes are more important.
The profile data table lists all the pizza choice combinations that you want to present to the subjects. Each
choice combination is given an ID. The profile data table is shown in Figure 16.1.
Figure 16.1 Pizza Profile Data Table
For the actual survey or experiment, each subject is given four trials, where each trial consists of stating his
or her preference between two choice profiles (Choice1 and Choice2). The choice profiles given for each
trial are referred to as a choice set. One subject’s choice trials can be different from another subject’s trials.
Refer to the DOE Choice Design platform for generating optimal choice designs. Twelve runs from the first
three subjects are shown in Figure 16.2.