Thurstonian Models for Intensity Ratings
Ennis, D. M. (1999). IFPress, 2(3) 2-3.
Products and concepts are often evaluated on rating scales to quantify degree of liking, level of purchase interest, intensity of an attribute, degree of difference or level of agreement with a statement. Rating scales are constructed in many different ways, but usually involve options labeled with numbers, words or symbols. In some cases a particular option has a special label, such as “just right” or “same as reference.” Scales may involve labels for every option, such as the words on the 9-point acceptability scale; other scales have labels only at the end points.
Figure 1a. Product distributions and decision boundaries on an interval scale modeled from 7-point numerical ratings.